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Sample records for low-energy shock waves

  1. Low-energy proton increases associated with interplanetary shock waves.

    Science.gov (United States)

    Palmeira, R. A. R.; Allum, F. R.; Rao, U. R.

    1971-01-01

    Impulsive increases in the low energy proton flux observed by the Explorer 34 satellite, in very close time association with geomagnetic storm sudden commencements are described. It is shown that these events are of short duration (20-30 min) and occur only during the decay phase of a solar cosmic-ray flare event. The differential energy spectrum and the angular distribution of the direction of arrival of the particles are discussed. Two similar increases observed far away from the earth by the Pioneer 7 and 8 deep-space probes are also presented. These impulsive increases are compared with Energetic Storm Particle events and their similarities and differences are discussed. A model is suggested to explain these increases, based on the sweeping and trapping of low energy cosmic rays of solar origin by the advancing shock front responsible for the sudden commencement detected on the earth.

  2. Can cellulite be treated with low-energy extracorporeal shock wave therapy?

    OpenAIRE

    Fiorenzo Angehrn; Christoph Kuhn; Axel Voss

    2008-01-01

    Fiorenzo Angehrn1, Christoph Kuhn1, Axel Voss21Klinik Piano, Gottstattstrasse 24, Biel, Switzerland; 2SwiTech Medical AG, Kreuzlingen, SwitzerlandAbstract: The present study investigates the effects of low-energy defocused extracorporeal generated shock waves on collagen structure of cellulite afflicted skin. Cellulite measurement using high-resolution ultrasound technology was performed before and after low-energy defocused extracorporeal shock wave therapy (ESWT) in 21 female subjects. ESWT...

  3. Can cellulite be treated with low-energy extracorporeal shock wave therapy?

    Science.gov (United States)

    Angehrn, Fiorenzo; Kuhn, Christoph; Voss, Axel

    2007-01-01

    The present study investigates the effects of low-energy defocused extracorporeal generated shock waves on collagen structure of cellulite afflicted skin. Cellulite measurement using high-resolution ultrasound technology was performed before and after low-energy defocused extracorporeal shock wave therapy (ESWT) in 21 female subjects. ESWT was applied onto the skin at the lateral thigh twice a week for a period of six weeks. Results provide evidence that low-energy defocused ESWT caused remodeling of the collagen within the dermis of the tested region. Improving device-parameters and therapy regimes will be essential for future development of a scientific based approach to cellulite treatment. PMID:18225463

  4. Potential applications of low-energy shock waves in functional urology.

    Science.gov (United States)

    Wang, Hung-Jen; Cheng, Jai-Hong; Chuang, Yao-Chi

    2017-08-01

    A shock wave, which carries energy and can propagate through a medium, is a type of continuous transmitted sonic wave with a frequency of 16 Hz-20 MHz. It is accompanied by processes involving rapid energy transformations. The energy associated with shock waves has been harnessed and used for various applications in medical science. High-energy extracorporeal shock wave therapy is the most successful application of shock waves, and has been used to disintegrate urolithiasis for 30 years. At lower energy levels, however, shock waves have enhanced expression of vascular endothelial growth factor, endothelial nitric oxide synthase, proliferating cell nuclear antigen, chemoattractant factors and recruitment of progenitor cells; shock waves have also improved tissue regeneration. Low-energy shock wave therapy has been used clinically with musculoskeletal disorders, ischemic cardiovascular disorders and erectile dysfunction, through the mechanisms of neovascularization, anti-inflammation and tissue regeneration. Furthermore, low-energy shock waves have been proposed to temporarily increase tissue permeability and facilitate intravesical drug delivery. The present review article provides information on the basics of shock wave physics, mechanisms of action on the biological system and potential applications in functional urology. © 2017 The Japanese Urological Association.

  5. Can cellulite be treated with low-energy extracorporeal shock wave therapy?

    Directory of Open Access Journals (Sweden)

    Fiorenzo Angehrn

    2008-01-01

    Full Text Available Fiorenzo Angehrn1, Christoph Kuhn1, Axel Voss21Klinik Piano, Gottstattstrasse 24, Biel, Switzerland; 2SwiTech Medical AG, Kreuzlingen, SwitzerlandAbstract: The present study investigates the effects of low-energy defocused extracorporeal generated shock waves on collagen structure of cellulite afflicted skin. Cellulite measurement using high-resolution ultrasound technology was performed before and after low-energy defocused extracorporeal shock wave therapy (ESWT in 21 female subjects. ESWT was applied onto the skin at the lateral thigh twice a week for a period of six weeks. Results provide evidence that low-energy defocused ESWT caused remodeling of the collagen within the dermis of the tested region. Improving device-parameters and therapy regimes will be essential for future development of a scientific based approach to cellulite treatment.Keywords: cellulite (gynoid lipodystrophy, collagen structure of dermis, collagenometry high-resolution ultrasound of skin, low-energy defocused extracorporeal shock wave therapy (ESWT, septa of subcutaneous connective tissue

  6. Acceleration of low-energy protons and alpha particles at interplanetary shock waves

    Science.gov (United States)

    Scholer, M.; Hovestadt, D.; Ipavich, F. M.; Gloeckler, G.

    1983-01-01

    The low-energy protons and alpha particles in the energy range 30 keV/charge to 150 keV/charge associated with three different interplanetary shock waves in the immediate preshock and postshock region are studied using data obtained by the ISEE 3. The spatial distributions in the preshock and postshock medium are presented, and the dependence of the phase space density at different energies on the distance from the shock and on the form of the distribution function of both species immediately at the shock is examined. It is found that in the preshock region the particles are flowing in the solar wind frame of reference away from the shock and in the postshock medium the distribution is more or less isotropic in this frame of reference. The distribution function in the postshock region can be represented by a power law in energy which has the same spectral exponent for both protons and alpha particles. It is concluded that the first-order Fermi acceleration process can consistently explain the data, although the spectra of diffuse bow shock associated particles are different from the spectra of the interplanetary shock-associated particles in the immediate vicinity of the shock. In addition, the mean free path of the low energy ions in the preshock medium is found to be considerably smaller than the mean free path determined by the turbulence of the background interplanetary medium.

  7. Low-energy extracorporal shock wave therapy for persistent tennis elbow.

    Science.gov (United States)

    Rompe, J D; Hopf, C; Küllmer, K; Heine, J; Bürger, R; Nafe, B

    1996-01-01

    Fifty patients who suffered from persistent tennis elbow for more than 12 months, and were referred for surgical treatment, were assigned at random to 2 groups of low-energy extracorporal shock wave therapy. Group I received a total of 3000 impulses of 0.08 mJ/mm2; group II (controls) 30 impulses of 0.08 mJ/mm2. Follow up was after 3 and 12 weeks. We found no significant differences between the 2 groups before treatment, there was but significant relief of pain and improvement of function in group I with good or excellent outcome in 56% at the last evaluation.

  8. Molecular mechanisms of the angiogenic effects of low-energy shock wave therapy: roles of mechanotransduction.

    Science.gov (United States)

    Hatanaka, Kazuaki; Ito, Kenta; Shindo, Tomohiko; Kagaya, Yuta; Ogata, Tsuyoshi; Eguchi, Kumiko; Kurosawa, Ryo; Shimokawa, Hiroaki

    2016-09-01

    We have previously demonstrated that low-energy extracorporeal cardiac shock wave (SW) therapy improves myocardial ischemia through enhanced myocardial angiogenesis in a porcine model of chronic myocardial ischemia and in patients with refractory angina pectoris. However, the detailed molecular mechanisms for the SW-induced angiogenesis remain unclear. In this study, we thus examined the effects of SW irradiation on intracellular signaling pathways in vitro. Cultured human umbilical vein endothelial cells (HUVECs) were treated with 800 shots of low-energy SW (1 Hz at an energy level of 0.03 mJ/mm(2)). The SW therapy significantly upregulated mRNA expression and protein levels of vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS). The SW therapy also enhanced phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2) and Akt. Furthermore, the SW therapy enhanced phosphorylation of caveolin-1 and the expression of HUTS-4 that represents β1-integrin activity. These results suggest that caveolin-1 and β1-integrin are involved in the SW-induced activation of angiogenic signaling pathways. To further examine the signaling pathways involved in the SW-induced angiogenesis, HUVECs were transfected with siRNA of either β1-integrin or caveolin-1. Knockdown of either caveolin-1 or β1-integrin suppressed the SW-induced phosphorylation of Erk1/2 and Akt and upregulation of VEGF and eNOS. Knockdown of either caveolin-1 or β1-integrin also suppressed SW-induced enhancement of HUVEC migration in scratch assay. These results suggest that activation of mechanosensors on cell membranes, such as caveolin-1 and β1-integrin, and subsequent phosphorylation of Erk and Akt may play pivotal roles in the SW-induced angiogenesis.

  9. Immediate Dose-Response Effect of High-Energy Versus Low-Energy Extracorporeal Shock Wave Therapy on Cutaneous Microcirculation.

    Science.gov (United States)

    Kraemer, Robert; Sorg, Heiko; Forstmeier, Vinzent; Knobloch, Karsten; Liodaki, Eirini; Stang, Felix Hagen; Mailaender, Peter; Kisch, Tobias

    2016-12-01

    Elucidation of the precise mechanisms and therapeutic options of extracorporeal shock wave therapy (ESWT) is only at the beginning. Although immediate real-time effects of ESWT on cutaneous hemodynamics have recently been described, the dose response to different ESWT energies in cutaneous microcirculation has never been examined. Thirty-nine Sprague-Dawley rats were randomly assigned to three groups that received either focused high-energy shock waves (group A: total of 1000 impulses, 10 J) to the lower leg of the hind limb, focused low-energy shock waves (group B: total of 300 impulses, 1 J) or placebo shock wave treatment (group C: 0 impulses, 0 J) using a multimodality shock wave delivery system (Duolith SD-1 T-Top, Storz Medical, Tägerwilen, Switzerland). Immediate microcirculatory effects were assessed with the O2C (oxygen to see) system (LEA Medizintechnik, Giessen, Germany) before and for 20 min after application of ESWT. Cutaneous tissue oxygen saturation increased significantly higher after high-energy ESWT than after low-energy and placebo ESWT (A: 29.4% vs. B: 17.3% vs. C: 3.3%; p = 0.003). Capillary blood velocity was significantly higher after high-energy ESWT and lower after low-energy ESWT versus placebo ESWT (group A: 17.8% vs. group B: -22.1% vs. group C: -5.0%, p = 0.045). Post-capillary venous filling pressure was significantly enhanced in the high-energy ESWT group in contrast to the low-energy ESWT and placebo groups (group A: 25% vs. group B: 2% vs. group C: -4%, p = 0.001). Both high-energy and low-energy ESWT affect cutaneous hemodynamics in a standard rat model. High-energy ESWT significantly increases parameters of cutaneous microcirculation immediately after application, resulting in higher tissue oxygen saturation, venous filling pressure and blood velocity, which suggests higher tissue perfusion with enhanced oxygen saturation, in contrast to low-energy as well as placebo ESWT. Low-energy ESWT also increased tissue oxygen

  10. Effects of high- and low-energy radial shock waves therapy combined with physiotherapy in the treatment of rotator cuff tendinopathy: a retrospective study.

    Science.gov (United States)

    Su, Xiangzheng; Li, Zhongli; Liu, Zhengsheng; Shi, Teng; Xue, Chao

    2017-06-09

    The aim of this study was to investigate the efficacy of high- and low-energy radial shock waves combined with physiotherapy for rotator cuff tendinopathy patients. Data from rotator cuff tendinopathy patients received high- or low-energy radial shock waves combined with physiotherapy or physiotherapy alone were collected. The Constant and Murley score and visual analog scale score were collected to assess the effectiveness of treatment in three groups at 4, 8, 12, and 24 weeks. In total, 94 patients were involved for our retrospective study. All groups showed remarkable improvement in the visual analog scale and Constant and Murley score compared to baseline at 24 weeks. The high-energy radial shock waves group had more marked improvement in the Constant and Murley score compared to the physiotherapy group at 4 and 8 weeks and at 4 weeks when compared with low-energy group. Furthermore, high-energy radial shock waves group had superior results on the visual analog scale at 4, 8, and 12 weeks compared to low-energy and physiotherapy groups. This retrospective study supported the usage of high-energy radial shock waves as a supplementary therapy over physiotherapy alone for rotator cuff tendinopathy by relieving the symptoms rapidly and maintaining symptoms at a satisfactory level for 24 weeks. Implications for Rehabilitation High-energy radial shock waves can be a supplemental therapy to physiotherapy for rotator cuff tendinopathy. We recommend the usage of high-energy radial shock waves during the first 5 weeks, at an interval of 7 days, of physiotherapy treatment. High-energy radial shock waves treatment combined with physiotherapy can benefit rotator cuff tendinopathy by relieving symptoms rapidly and maintain these improvements at a satisfactory level for quite a long time.

  11. EFFECT OF LOW ENERGY VERSUS MEDIUM ENERGY RADIAL SHOCK WAVE THERAPY IN THE TREATMENT OF CHRONIC PLANTER FASCIITIS

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    Khaled Z. Fouda

    2016-02-01

    Full Text Available Background: Plantar fasciitis (PF is the most common cause of heel pain and it can often be a challenge for clinicians to treat successfully. Radial shock wave therapy (RSWT has been introduced recently for treatment of musculoskeletal disorders. Different energy levels of shock wave therapy have been used in the literatures for treatment of PF with no clear settled parameters. Therefore, the purpose of this study was intended to investigate and compare the efficacy of two different energy levels of RSWT on PF patients. Methods: Forty patients having unilateral chronic PF were recruited for the study from orthopedic outpatient clinics of Cairo University hospitals and National Institute of Neuromotor System Cairo Egypt, with a mean age of (47.15±4.57 years. Patients were randomly assigned into two equal groups. Group (A treated with low intensity level of 1.6 bars (0.16 mJ/mm2 RSWT and group (B treated with medium intensity level of 4 bars (0.38 mJ/mm2 RSWT. Functional assessment of the foot based on Foot Function Index (FFI and Present pain intensity was measured during rest by Visual Analogue Scale (VAS. Results: There was as significant decreased in the total FFI scores from (118.42 ±6.51 to (81.37 ±3.46 for group (A and from (118.93 ±6.85 to (58.50 ±3.22 for group (B. Also regarding VAS Scores there was as significant decreased in the pain intensity from (5.11 ±0.41 to (2.85 ±0.31 for group (A and from (4.95 ±0.39 to (2.05 ±0.22 for group (B. Conclusion: Radial shock wave therapy is an effective modality that should be considered in the treatment of chronic PF, while the medium energy level RSWT is better than the low energy level RSWT in regarding to the measured treatment outcomes.

  12. Endogenous Stem Cells Were Recruited by Defocused Low-Energy Shock Wave in Treating Diabetic Bladder Dysfunction.

    Science.gov (United States)

    Jin, Yang; Xu, Lina; Zhao, Yong; Wang, Muwen; Jin, Xunbo; Zhang, Haiyang

    2016-12-05

    Defocused low-energy shock wave (DLSW) has been shown effects on activating mesenchymal stromal cells (MSCs) in vitro. In this study, recruitment of endogenous stem cells was firstly examined as an important pathway during the healing process of diabetic bladder dysfunction (DBD) treated by DLSW in vivo. Neonatal rats received intraperitoneal injection of 5-ethynyl-2-deoxyuridine (EdU) and then DBD rat model was created by injecting streptozotocin. Four weeks later, DLSW treatment was performed. Afterward, their tissues were examined by histology. Meanwhile, adipose tissue-derived stem cells (ADSCs) were treated by DLSW in vitro. Results showed DLSW ameliorated voiding function of diabetic rats by recruiting EdU(+)Stro-1(+)CD34(-) endogenous stem cells to release abundant nerve growth factor (NGF) and vascular endothelial growth factor (VEGF). Some EdU(+) cells overlapped with staining of smooth muscle actin. After DLSW treatment, ADSCs showed higher migration ability, higher expression level of stromal cell-derived factor-1 and secreted more NGF and VEGF. In conclusion, DLSW could ameliorate DBD by recruiting endogenous stem cells. Beneficial effects were mediated by secreting NGF and VEGF, resulting into improved innervation and vascularization in bladder.

  13. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function [Retraction

    Directory of Open Access Journals (Sweden)

    Wang L

    2016-10-01

    Full Text Available Wang L, Jiang Y, Jiang Z, Han L. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function. Neuropsychiatr Dis Treat. 2016 Aug 31;12:2189–2198. doi: 10.2147/NDT.S82864.This article was found to have plagiarized the content of:Low-energy extracorporeal shock wave therapy promotes vascular endothelial growth factor expression and improves locomotor recovery after spinal injury published in the Journal of Neurosurgery in 2014 (J Neurosurg. 121: 1514–1525, 2014.Accordingly, Dr Pinder, Editor-in-Chief of Neuropsychiatric Disease and Treatment has decided to issue a Retraction notice and advise the academic supervisors of Dr Wang et al of this matter. This Retraction relates to

  14. Low-energy extracorporeal shock wave therapy improves microcirculation blood flow of ischemic limbs in patients with peripheral arterial disease: pilot study.

    Science.gov (United States)

    Tara, Shuhei; Miyamoto, Masaaki; Takagi, Gen; Kirinoki-Ichikawa, Sonoko; Tezuka, Akito; Hada, Tomohito; Takagi, Ikuyo

    2014-01-01

    Because direct application of low-energy shock waves induces angiogenesis, we investigated the safety and efficacy of this new therapy to develop a noninvasive method of repeatable therapeutic angiogenesis for treating peripheral arterial disease (PAD). The subjects were 10 patients who had symptomatic PAD and limited ischemia in a below-the-knee artery. Low-energy shock waves were directly applied to the calf muscles 6 times every other day. Intracorporeal changes were evaluated with ultrasonography to determine adverse effects of therapy. To assess blood flow of the microcirculation, transcutaneous oxygen tension (TcPO2), skin perfusion pressure (SPP), and (99m)technetium-tetrofosmin ((99m)Tc-TF) scintigraphy were performed before and after therapy. The TcPO2 was measured while subjects inhaled pure oxygen (maximum TcPO2). The (99m)Tc-TF perfusion index was determined as a ratio of uptake in muscle to that in the brain (control) for quantitative analysis. No adverse effects were noted in any patient. Maximum TcPO2 values increased significantly on the calf (57.3±28.4 to 71.0±14.5 mm Hg, p=0.044) and the dorsum of the foot (52.2±21.8 to 76.1±17.9 mm Hg, p=0.012). The SPP tended to increase after therapy on the dorsum and plantar surfaces of the foot, but the differences were not significant. The (99m)Tc-TF perfusion index in the foot significantly increased (0.48±0.09 to 0.61±0.12, p=0.0013), but that in the leg did not change. We have demonstrated that low-energy shock wave therapy is safe and can restore blood flow in the microcirculation in patients with symptomatic PAD.

  15. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function

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    Wang, Lei; Jiang, Yuquan; Jiang, Zheng; Han, Lizhang

    2016-01-01

    Background Latest studies show that low-energy extracorporeal shock wave therapy (ESWT) can upregulate levels of vascular endothelial growth factor (VEGF). VEGF can ease nervous tissue harm after spinal cord injury (SCI). This study aims to explore whether low-energy ESWT can promote expression of VEGF, protect nervous tissue after SCI, and improve motor function. Methods Ninety adult female rats were divided into the following groups: Group A (simple laminectomy), Group B (laminectomy and low-energy ESWT), Group C (spinal cord injury), and Group D (spinal cord injury and low-energy ESWT). Impinger was used to cause thoracic spinal cord injury. Low-energy ESWT was applied as treatment after injury three times a week, for 3 weeks. After SCI, the Basso, Beattie, and Bresnahan (BBB) scale was used to evaluate motor function over a period of 42 days at different time points. Hematoxylin and eosin (HE) staining was used to evaluate nerve tissue injury. Neuronal nuclear antigen (NeuN) staining was also used to evaluate loss of neurons. Polymerase chain reaction was used to detect messenger RNA (mRNA) expression of VEGF and its receptor fms-like tyrosine kinase 1 (Flt-1). Immunostaining was used to evaluate VEGF protein expression level in myeloid tissue. Results BBB scores of Groups A and B showed no significant result related to dyskinesia. HE and NeuN staining indicated that only using low-energy ESWT could not cause damage of nervous tissue in Group B. Recovery of motor function at 7, 35, and 42 days after SCI in Group D was better than that in Group C (Ptherapy for spinal injury. PMID:27621630

  16. Low-energy extracorporeal shock wave therapy for promotion of vascular endothelial growth factor expression and angiogenesis and improvement of locomotor and sensory functions after spinal cord injury.

    Science.gov (United States)

    Yahata, Kenichiro; Kanno, Haruo; Ozawa, Hiroshi; Yamaya, Seiji; Tateda, Satoshi; Ito, Kenta; Shimokawa, Hiroaki; Itoi, Eiji

    2016-12-01

    OBJECTIVE Extracorporeal shock wave therapy (ESWT) is widely used to treat various human diseases. Low-energy ESWT increases expression of vascular endothelial growth factor (VEGF) in cultured endothelial cells. The VEGF stimulates not only endothelial cells to promote angiogenesis but also neural cells to induce neuroprotective effects. A previous study by these authors demonstrated that low-energy ESWT promoted expression of VEGF in damaged neural tissue and improved locomotor function after spinal cord injury (SCI). However, the neuroprotective mechanisms in the injured spinal cord produced by low-energy ESWT are still unknown. In the present study, the authors investigated the cell specificity of VEGF expression in injured spinal cords and angiogenesis induced by low-energy ESWT. They also examined the neuroprotective effects of low-energy ESWT on cell death, axonal damage, and white matter sparing as well as the therapeutic effect for improvement of sensory function following SCI. METHODS Adult female Sprague-Dawley rats were divided into the SCI group (SCI only) and SCI-SW group (low-energy ESWT applied after SCI). Thoracic SCI was produced using a New York University Impactor. Low-energy ESWT was applied to the injured spinal cord 3 times a week for 3 weeks after SCI. Locomotor function was evaluated using the Basso, Beattie, and Bresnahan open-field locomotor score for 42 days after SCI. Mechanical and thermal allodynia in the hindpaw were evaluated for 42 days. Double staining for VEGF and various cell-type markers (NeuN, GFAP, and Olig2) was performed at Day 7; TUNEL staining was also performed at Day 7. Immunohistochemical staining for CD31, α-SMA, and 5-HT was performed on spinal cord sections taken 42 days after SCI. Luxol fast blue staining was performed at Day 42. RESULTS Low-energy ESWT significantly improved not only locomotion but also mechanical and thermal allodynia following SCI. In the double staining, expression of VEGF was observed in Neu

  17. Effect of low-energy extracorporeal shock wave on vascular regeneration after spinal cord injury and the recovery of motor function

    Directory of Open Access Journals (Sweden)

    Wang L

    2016-08-01

    Full Text Available Lei Wang, Yuquan Jiang, Zheng Jiang, Lizhang Han Department of Neurosurgery, Qilu Hospital of Shandong University, Jinan, People’s Republic of China Background: Latest studies show that low-energy extracorporeal shock wave therapy (ESWT can upregulate levels of vascular endothelial growth factor (VEGF. VEGF can ease nervous tissue harm after spinal cord injury (SCI. This study aims to explore whether low-energy ESWT can promote expression of VEGF, protect nervous tissue after SCI, and improve motor function.Methods: Ninety adult female rats were divided into the following groups: Group A (simple laminectomy, Group B (laminectomy and low-energy ESWT, Group C (spinal cord injury, and Group D (spinal cord injury and low-energy ESWT. Impinger was used to cause thoracic spinal cord injury. Low-energy ESWT was applied as treatment after injury three times a week, for 3 weeks. After SCI, the Basso, Beattie, and Bresnahan (BBB scale was used to evaluate motor function over a period of 42 days at different time points. Hematoxylin and eosin (HE staining was used to evaluate nerve tissue injury. Neuronal nuclear antigen (NeuN staining was also used to evaluate loss of neurons. Polymerase chain reaction was used to detect messenger RNA (mRNA expression of VEGF and its receptor fms-like tyrosine kinase 1 (Flt-1. Immunostaining was used to evaluate VEGF protein expression level in myeloid tissue.Results: BBB scores of Groups A and B showed no significant result related to dyskinesia. HE and NeuN staining indicated that only using low-energy ESWT could not cause damage of nervous tissue in Group B. Recovery of motor function at 7, 35, and 42 days after SCI in Group D was better than that in Group C (P<0.05. Compared with Group C, number of NeuN-positive cells at 42 days after SCI increased significantly (P<0.05. The mRNA levels of VEGF and Flt-1 and VEGF expression at 7 days after SCI in Group D were significantly higher than those in Group C (P<0

  18. Evaluation of the Effect of Different Doses of Low Energy Shock Wave Therapy on the Erectile Function of Streptozotocin (STZ-Induced Diabetic Rats

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    Zhong-Cheng Xin

    2013-05-01

    Full Text Available To investigate the therapeutic effect of different doses of low energy shock wave therapy (LESWT on the erectile dysfunction (ED in streptozotocin (STZ induced diabetic rats. SD rats (n = 75 were randomly divided into 5 groups (normal control, diabetic control, 3 different dose LESWT treated diabetic groups. Diabetic rats were induced by intra-peritoneal injection of STZ (60 mg/kg and rats with fasting blood glucose ≥ 300 mg/dL were selected as diabetic models. Twelve weeks later, different doses of LESWT (100, 200 and 300 shocks each time treatment on penises were used to treat ED (7.33 MPa, 2 shocks/s three times a week for two weeks. The erectile function was evaluated by intracavernous pressure (ICP after 1 week washout period. Then the penises were harvested for histological study. The results showed LESWT could significantly improve the erectile function of diabetic rats, increase smooth muscle and endothelial contents, up-regulate the expression of α-SMA, vWF, nNOS and VEGF, and down- regulate the expression of RAGE in corpus cavernosum. The therapeutic effect might relate to treatment dose positively, and the maximal therapeutic effect was noted in the LESWT300 group. Consequently, 300 shocks each time might be the ideal LESWT dose for diabetic ED treatment.

  19. Low Energy Extracorporeal Cardiac Shock Wave Therapy for Ischemic Heart Disease%低能量体外冲击波治疗缺血性心脏病

    Institute of Scientific and Technical Information of China (English)

    王蹿蹿; 谢华宁; 郭宏

    2009-01-01

    Ischemic heart disease is a leading cause of death. The low energy extracorporeal cardiac shock wave is a novel therapy which could improve symptoms and reduce nitroglycerin use for the patients of ischemia heart disease by upregulating mRNA expression of VEGF and its receptor Flt-1, improving myocardial perfusion and left ventricular remodeling.%缺血性心脏病是导致死亡的主要原因.低能量体外冲击波治疗可以通过增加血管内皮生长因子的mRNA的表达、增加心肌有效灌注和改善左室重塑,从而改善缺血性心脏病患者的症状,减少硝酸甘油的服用,达到治疗缺血性心脏病的目的.

  20. [Analgesic effect of low energy extracorporeal shock waves in tendinosis calcarea, epicondylitis humeri radialis and plantar fasciitis].

    Science.gov (United States)

    Maier, M; Dürr, H R; Köhler, S; Staupendahl, D; Pfahler, M; Refior, H J; Meier, M

    2000-01-01

    Is there a pain reduction at the application site after extracorporeal shockwave application for tendinitis calcarea, epicondylitis radialis and plantar fasziitis? In a prospective study 85 patients were observed. Shockwave application was performed three or five times using low energies (0.09-0.18 ml/mm2). Before and after shockwave application pain was evaluated using SF-36 score and Visual Analog Scale (VAS). After 5 months for all three indications a significant improvement of the pain situation could be reached. Patients with plantar fasziitis demonstrated the highest decrease of pain, followed by tendinosis calcarea and epicondylitis radialis. The number of applications had no influence to the clinical result of the ESWT. In the present study the analgetic effect of ESWT after repeated low-energy application was described for the standard indications.

  1. Low-Energy Extracorporeal Shock-Wave Therapy in the Treatment of Chronic Insertional Achilles Tendinopathy: A Case Series

    OpenAIRE

    Vito Pavone; Luca Cannavò; Antonio Di Stefano; Gianluca Testa; Luciano Costarella; Giuseppe Sessa

    2016-01-01

    Introduction. We report the results of a series of 40 patients with chronic insertional Achilles tendinopathy treated with low-energy ESWT after the failure of a 3-month program of eccentric exercises alone. Methods and Materials. 40 patients, 28 (70%) males and 12 (30%) females, were treated between January and December 2014. All patients were previously treated with only eccentric exercises for a 3-month period. The treatment protocol included 4 sessions of ESWT with a 2-week interval, from...

  2. Low-Energy Extracorporeal Shock-Wave Therapy in the Treatment of Chronic Insertional Achilles Tendinopathy: A Case Series

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    Vito Pavone

    2016-01-01

    Full Text Available Introduction. We report the results of a series of 40 patients with chronic insertional Achilles tendinopathy treated with low-energy ESWT after the failure of a 3-month program of eccentric exercises alone. Methods and Materials. 40 patients, 28 (70% males and 12 (30% females, were treated between January and December 2014. All patients were previously treated with only eccentric exercises for a 3-month period. The treatment protocol included 4 sessions of ESWT with a 2-week interval, from 800 shots in each one (4 Hz, 14 KeV, together with eccentric exercises. Visual Analogue Scale (VAS and American Orthopedic Foot and Ankle Society (AOFAS Hindfoot score were recorded. Results. At the 12-month follow-up, 26 (65.0% patients did not complain about pain (VAS 4. There was no significative improvement in both scores after eccentric exercises alone. Mean VAS improvement was 5.8±1.3 SD points (P<0.001. Mean AOFAS Hindfoot score improvement was 19.8±5.0 SD points (P<0.001. Conclusions. ESWT is recommended, in combination with an eccentric exercise program, in patients with chronic Achilles tendinopathy being both insertional and not.

  3. Low-Energy Extracorporeal Shock-Wave Therapy in the Treatment of Chronic Insertional Achilles Tendinopathy: A Case Series

    Science.gov (United States)

    Pavone, Vito; Di Stefano, Antonio; Testa, Gianluca; Costarella, Luciano; Sessa, Giuseppe

    2016-01-01

    Introduction. We report the results of a series of 40 patients with chronic insertional Achilles tendinopathy treated with low-energy ESWT after the failure of a 3-month program of eccentric exercises alone. Methods and Materials. 40 patients, 28 (70%) males and 12 (30%) females, were treated between January and December 2014. All patients were previously treated with only eccentric exercises for a 3-month period. The treatment protocol included 4 sessions of ESWT with a 2-week interval, from 800 shots in each one (4 Hz, 14 KeV), together with eccentric exercises. Visual Analogue Scale (VAS) and American Orthopedic Foot and Ankle Society (AOFAS) Hindfoot score were recorded. Results. At the 12-month follow-up, 26 (65.0%) patients did not complain about pain (VAS 4). There was no significative improvement in both scores after eccentric exercises alone. Mean VAS improvement was 5.8 ± 1.3 SD points (P < 0.001). Mean AOFAS Hindfoot score improvement was 19.8 ± 5.0 SD points (P < 0.001). Conclusions. ESWT is recommended, in combination with an eccentric exercise program, in patients with chronic Achilles tendinopathy being both insertional and not. PMID:27843949

  4. Combination of low-energy shock-wave therapy and bone marrow mesenchymal stem cell transplantation to improve the erectile function of diabetic rats.

    Science.gov (United States)

    Shan, Hai-Tao; Zhang, Hai-Bo; Chen, Wen-Tao; Chen, Feng-Zhi; Wang, Tao; Luo, Jin-Tai; Yue, Min; Lin, Ji-Hong; Wei, An-Yang

    2017-01-01

    Stem cell transplantation and low-energy shock-wave therapy (LESWT) have emerged as potential and effective treatment protocols for diabetic erectile dysfunction. During the tracking of transplanted stem cells in diabetic erectile dysfunction models, the number of visible stem cells was rather low and decreased quickly. LESWT could recruit endogenous stem cells to the cavernous body and improve the microenvironment in diabetic cavernous tissue. Thus, we deduced that LESWT might benefit transplanted stem cell survival and improve the effects of stem cell transplantation. In this research, 42 streptozotocin-induced diabetic rats were randomized into four groups: the diabetic group (n = 6), the LESWT group (n = 6), the bone marrow-derived mesenchymal stem cell (BMSC) transplantation group (n = 15), and the combination of LESWT and BMSC transplantation group (n = 15). One and three days after BMSC transplantation, three rats were randomly chosen to observe the survival numbers of BMSCs in the cavernous body. Four weeks after BMSC transplantation, the following parameters were assessed: the surviving number of transplanted BMSCs in the cavernous tissue, erectile function, real-time polymerase chain reaction, and penile immunohistochemical assessment. Our research found that LESWT favored the survival of transplanted BMSCs in the cavernous body, which might be related to increased stromal cell-derived factor-1 expression and the enhancement of angiogenesis in the diabetic cavernous tissue. The combination of LESWT and BMSC transplantation could improve the erectile function of diabetic erectile function rats more effectively than LESWT or BMSC transplantation performed alone.

  5. Shock Waves

    CERN Document Server

    Jiang, Z

    2005-01-01

    The International Symposium on Shock Waves (ISSW) is a well established series of conferences held every two years in a different location. A unique feature of the ISSW is the emphasis on bridging the gap between physicists and engineers working in fields as different as gas dynamics, fluid mechanics and materials sciences. The main results presented at these meetings constitute valuable proceedings that offer anyone working in this field an authoritative and comprehensive source of reference.

  6. Technique report on the application and research of low energy and long-ditance shock wave by extracorporeal shock wave lithotripsy(Report of 380 cases)%低能量长间距体外冲击波碎石(附380例报告)

    Institute of Scientific and Technical Information of China (English)

    李航; 王连志

    2000-01-01

    目的:探讨低能量、长间距冲击波技术在体外冲击波碎石(ESWL)中的应用,以及X线、B超双定位技术在ESWL中的优势。方法:应用低能量、长间距冲击波及X线、B超双定位技术进行ESWL380例。结果:380例均获成功,结石排净或残石颗粒直径均<3 mm。所有患者术后都出现轻微血尿,肾结石者12 h内消失,输尿管结石者1~2次后消失。58例局部皮肤出现点状红斑。¨例形成输尿管石街,经再次ESWL治疗而消失。肾被膜下血肿1例,经对症处理2周后血肿被吸收。结论:低能量、长间距冲击波技术碎石率高,具有血尿时间短、无输尿管绞痛发作、肾被膜血肿发生率低等优点。X线、B超双定位技术值得推广。%Purpose:Through the application and research of the technique low energy and long-distanceshock wave by extracorporeal shock wave lithotripsy(ESWL)we intend to explore its application skills ,advantageof X-ray or B-mode ultrasonic examination in determining the location. Methods:We used the technique of lowenergy ,long-distance shock wave and X-ray or B-mode ultrasonic examination in determining the location to treat380 patients who suffered from calculus disease. Results :The 380 cases which we performed turned out to be verysuccessful. The technique of therapy with low energy,long-distance shock wave has greatly raised the cure rate ofcalculosis. It has a superiority with short time of hematuria,no ureteralgia and lower the occurrence rate of kidneyfilm hematoma. Conclusion :ESWL provides a new therapy to treat calculus disease. The technique of low energyand long-distance shock wave has great practical value, and the technique of X-ray or B-mode ultrasonicexamination in determining the location of calculus is well worth spreading.

  7. Chiral Shock Waves

    CERN Document Server

    Sen, Srimoyee

    2016-01-01

    We study shock waves in relativistic chiral matter. We argue that the conventional Rankine- Hugoinot relations are modified due to the presence of chiral transport phenomena. We show that the entropy discontinuity in a weak shock wave is linearly proportional to the pressure discontinuity when the effect of chiral transport becomes sufficiently large. We also show that rarefaction shock waves, which do not exist in usual nonchiral fluids, can appear in chiral matter. These features are exemplified by shock propagation in dense neutrino matter in the hydrodynamic regime.

  8. [Shock waves in orthopedics].

    Science.gov (United States)

    Haupt, G

    1997-05-01

    Extracorporeal shock waves have revolutionized urological stone treatment. Nowadays shock waves are widely used in orthopedics, too. This article reviews the applications of extracorporeal shock waves on bone and adjacent soft tissue. The osteoneogenetic effect of extracorporeal shock waves has been proven and can be used to treat pseudarthrosis with a success rate of around 75%. Shock waves have a positive effect in tennis and golfer's elbow, calcaneal spur, and the complex called "periarthritis humero-scapularis." The mechanism for this is not yet known, and results from large prospective and randomized studies are still lacking. However, the treatment has been performed many thousands of times. In patients in whom conservative treatment has failed surgery used to be the only choice, but its success rate barely exceeds that of shock wave therapy and surgery can still be done if shock wave therapy fails. Extracorporeal shock waves will have an impact on orthopedics comparable to its effect in urology. Scientific evaluations, professional certifications, quality assurance and reimbursement issues present great challenges.

  9. When Shock Waves Collide

    CERN Document Server

    Hartigan, P; Frank, A; Hansen, E; Yirak, K; Liao, A S; Graham, P; Wilde, B; Blue, B; Martinez, D; Rosen, P; Farley, D; Paguio, R

    2016-01-01

    Supersonic outflows from objects as varied as stellar jets, massive stars and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures and therefore a higher-excitation spectrum than an oblique one does. In this paper we summarize the results of a series of numerical simulations and laboratory experiments designed to quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and ...

  10. Shock wave reflection phenomena

    CERN Document Server

    Ben-dor, Gabi

    2007-01-01

    This book provides a comprehensive state-of-the-knowledge description of the shock wave reflection phenomena from a phenomenological point of view. The first part is a thorough introduction to oblique shock wave reflections, presenting the two major well-known reflection wave configurations, namely, regular (RR) and Mach (MR) reflections, the corresponding two- and three-shock theories, their analytical and graphical solution and the proposed transition boundaries between these two reflection-wave configurations. The second, third and fourth parts describe the reflection phenomena in steady, pseudo-steady and unsteady flows, respectively. Here, the possible specific types of reflection wave configurations are described, criteria for their formation and termination are presented and their governing equations are solved analytically and graphically and compared with experimental results. The resolution of the well-known von Neumann paradox and a detailed description of two new reflection-wave configurations - t...

  11. When Shock Waves Collide

    Science.gov (United States)

    Hartigan, P.; Foster, J.; Frank, A.; Hansen, E.; Yirak, K.; Liao, A. S.; Graham, P.; Wilde, B.; Blue, B.; Martinez, D.; Rosen, P.; Farley, D.; Paguio, R.

    2016-06-01

    Supersonic outflows from objects as varied as stellar jets, massive stars, and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures, and therefore a higher-excitation spectrum than does an oblique shock. In this paper, we summarize the results of a series of numerical simulations and laboratory experiments designed to quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and subcritical angles, larger ones persist in these situations and can regrow if the intersection angle changes to become more favorable. The experimental and numerical results show that although Mach stems occur only over a limited range of intersection angles and size scales, within these ranges they are relatively robust, and hence are a viable explanation for variable bright knots observed in Hubble Space Telescope images at the intersections of some bow shocks in stellar jets.

  12. Highly trabeculated structure of the human endocardium underlies asymmetrical response to low-energy monophasic shocks

    Science.gov (United States)

    Connolly, Adam; Robson, Matthew D.; Schneider, Jürgen; Burton, Rebecca; Plank, Gernot; Bishop, Martin J.

    2017-09-01

    Novel low-energy defibrillation therapies are thought to be driven by virtual-electrodes (VEs), due to the interaction of applied monophasic electric shocks with fine-scale anatomical structures within the heart. Significant inter-species differences in the cardiac (micro)-anatomy exist, however, particularly with respect to the degree of endocardial trabeculations, which may underlie important differences in response to low-energy defibrillation protocols. Understanding the interaction of monophasic electric fields with the specific human micro-anatomy is therefore imperative in facilitating the translation and optimisation of these promising experimental therapies to the clinic. In this study, we sought to investigate how electric fields from implanted devices interact with the highly trabeculated human endocardial surface to better understand shock success in order to help optimise future clinical protocols. A bi-ventricular human computational model was constructed from high resolution (350 μm) ex-vivo MR data, including anatomically accurate endocardial structures. Monophasic shocks were applied between a basal right ventricular catheter and an exterior ground. Shocks of varying strengths were applied with both anodal [positive right ventricle (RV) electrode] and cathodal (negative RV electrode) polarities at different states of tissue refractoriness and during induced arrhythmias. Anodal shocks induced isolated positive VEs at the distal side of "detached" trabeculations, which rapidly spread into hyperpolarised tissue on the surrounding endocardial surfaces following the shock. Anodal shocks thus depolarised more tissue 10 ms after the shock than cathodal shocks where the propagation of activation from VEs induced on the proximal side of "detached" trabeculations was prevented due to refractory endocardium. Anodal shocks increased arrhythmia complexity more than cathodal shocks during failed anti-arrhythmia shocks. In conclusion, multiple detached

  13. Low-energy protons associated with interplanetary shocks as a coherent population

    Energy Technology Data Exchange (ETDEWEB)

    Sanahuja, B.; Domingo, V.

    1987-07-01

    We investigate the flow pattern of low-energy protons (35--1600 keV) associated with interplanetary shocks observed by ISEE-3 between August 1978 and April 1980. The analysis of the shape of the distribution function in the solar wind frame and its temporal evolution indicates that the low-energy protons can behave as a coherent, independent population of particles in the solar wind. Ahead of the shock this population propagates along the magnetic field in the same direction as the solar wind flow, while after the passage of the perturbed region associated with the shock, it propagates in the opposite sense. The behavior of the flow pattern of this population through the shock front is discussed for the 17 largest events observed in this period. copyright American Geophysical Union 1987

  14. Shock wave treatment in medicine

    Indian Academy of Sciences (India)

    S K Shrivastava; Kailash

    2005-03-01

    Extracorporeal shock wave therapy in orthopedics and traumatology is still a young therapy method. Since the last few years the development of shock wave therapy has progressed rapidly. Shock waves have changed the treatment of urolithiasis substantially. Today shock waves are the first choice to treat kidney and urethral stones. Urology has long been the only medical field for shock waves in medicine. Meanwhile shock waves have been used in orthopedics and traumatology to treat insertion tendinitis, avascular necrosis of the head of femur and other necrotic bone alterations. Another field of shock wave application is the treatment of tendons, ligaments and bones on horses in veterinary medicine. In the present paper we discuss the basic theory and application of shock waves and its history in medicine. The idea behind using shock wave therapy for orthopedic diseases is the stimulation of healing in tendons, surrounding tissue and bones. This is a completely different approach compared to urology where shock waves are used for disintegration.

  15. The acceleration of low energy protons by quasi-perpendicular interplanetary shocks

    Energy Technology Data Exchange (ETDEWEB)

    Erdos, G. (Hungarian Academy of Sciences, Budapest (Hungary). Central Research Inst. for Physics); Balogh, A. (Imperial Coll. of Science and Technology, London (UK). Blackett Lab.)

    1990-03-01

    New aspects of the acceleration of low energy (35-1000 keV) protons by quasi-perpendicular interplanetary shocks are presented, using observations and numerical simulations. Time reverse trajectory calculations of particles are used to derive the behaviour of the angular distribution and spectrum through the shock. These calculations show that for simple planar geometries of the magnetic field and for a power-law spectrum of pre-accelerated particles the expected omnidirectional enhancements are smaller than observed. Pitch angle distributions in the vicinity of six interplanetary shocks have been determined from the measurements carried out onboard the ISEE-3 spacecraft. Reflection of particles was clearly identifiable by the loss cone type angular distribution observed upstream of the shock. Downstream of the shock, the shape and the energy dependence of the pitch angle distributions provide support for the scatter-free model in some cases. However, the observed spikes at the shock passage and bidirectional upstream distributions measured at the nearest to perpendicular shocks, together with other features of particle spectra and angular distributions which cannot be readily explained by model calculations suggest that fluctuations in the magnetic field might also seriously affect the acceleration process. (author).

  16. Bubble Dynamics and Shock Waves

    CERN Document Server

    2013-01-01

    This volume of the Shock Wave Science and Technology Reference Library is concerned with the interplay between bubble dynamics and shock waves. It is divided into four parts containing twelve chapters written by eminent scientists. Topics discussed include shock wave emission by laser generated bubbles (W Lauterborn, A Vogel), pulsating bubbles near boundaries (DM Leppinen, QX Wang, JR Blake), interaction of shock waves with bubble clouds (CD Ohl, SW Ohl), shock propagation in polydispersed bubbly liquids by model equations (K Ando, T Colonius, CE Brennen. T Yano, T Kanagawa,  M Watanabe, S Fujikawa) and by DNS (G Tryggvason, S Dabiri), shocks in cavitating flows (NA Adams, SJ Schmidt, CF Delale, GH Schnerr, S Pasinlioglu) together with applications involving encapsulated bubble dynamics in imaging (AA Doinikov, A Novell, JM Escoffre, A Bouakaz),  shock wave lithotripsy (P Zhong), sterilization of ships’ ballast water (A Abe, H Mimura) and bubbly flow model of volcano eruptions ((VK Kedrinskii, K Takayama...

  17. Radiative Shock Waves In Emerging Shocks

    Science.gov (United States)

    Drake, R. Paul; Doss, F.; Visco, A.

    2011-05-01

    In laboratory experiments we produce radiative shock waves having dense, thin shells. These shocks are similar to shocks emerging from optically thick environments in astrophysics in that they are strongly radiative with optically thick shocked layers and optically thin or intermediate downstream layers through which radiation readily escapes. Examples include shocks breaking out of a Type II supernova (SN) and the radiative reverse shock during the early phases of the SN remnant produced by a red supergiant star. We produce these shocks by driving a low-Z plasma piston (Be) at > 100 km/s into Xe gas at 1.1 atm. pressure. The shocked Xe collapses to > 20 times its initial density. Measurements of structure by radiography and temperature by several methods confirm that the shock wave is strongly radiative. We observe small-scale perturbations in the post-shock layer, modulating the shock and material interfaces. We describe a variation of the Vishniac instability theory of decelerating shocks and an analysis of associated scaling relations to account for the growth of these perturbations, identify how they scale to astrophysical systems such as SN 1993J, and consider possible future experiments. Collaborators in this work have included H.F. Robey, J.P. Hughes, C.C. Kuranz, C.M. Huntington, S.H. Glenzer, T. Doeppner, D.H. Froula, M.J. Grosskopf, and D.C. Marion ________________________________ * Supported by the US DOE NNSA under the Predictive Sci. Academic Alliance Program by grant DE-FC52-08NA28616, the Stewardship Sci. Academic Alliances program by grant DE-FG52-04NA00064, and the Nat. Laser User Facility by grant DE-FG03-00SF22021.

  18. Shock waves & explosions

    CERN Document Server

    Sachdev, PL

    2004-01-01

    Understanding the causes and effects of explosions is important to experts in a broad range of disciplines, including the military, industrial and environmental research, aeronautic engineering, and applied mathematics. Offering an introductory review of historic research, Shock Waves and Explosions brings analytic and computational methods to a wide audience in a clear and thorough way. Beginning with an overview of the research on combustion and gas dynamics in the 1970s and 1980s, the author brings you up to date by covering modeling techniques and asymptotic and perturbative methods and ending with a chapter on computational methods.Most of the book deals with the mathematical analysis of explosions, but computational results are also included wherever they are available. Historical perspectives are provided on the advent of nonlinear science, as well as on the mathematical study of the blast wave phenomenon, both when visualized as a point explosion and when simulated as the expansion of a high-pressure ...

  19. Freezing of low energy excitations in charge density wave glasses.

    Science.gov (United States)

    Staresinic, D; Zaitsev-Zotov, S V; Baklanov, N I; Biljaković, K

    2008-03-07

    Thermally stimulated discharge current measurements were performed to study slow relaxation processes in two canonical charge density wave systems K(0.3)MoO(3) and o-TaS(3). Two relaxation processes were observed and characterized in each system, corroborating the results of dielectric spectroscopy. Our results are consistent with the scenario of the glass transition on the charge density wave superstructure level. In particular, the results directly prove the previously proposed criterion of charge density wave freezing based on the interplay of charge density wave pinning by impurities and screening by free carriers. In addition, we obtained new information on distribution of relaxation parameters, as well as on nonlinear dielectric response both below and above the threshold field for charge density wave sliding.

  20. Oscillating nonlinear acoustic shock waves

    DEFF Research Database (Denmark)

    Gaididei, Yuri; Rasmussen, Anders Rønne; Christiansen, Peter Leth

    2016-01-01

    We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show...... that at resonance a stationary state arise consisting of multiple oscillating shock waves. Off resonance driving leads to a nearly linear oscillating ground state but superimposed by bursts of a fast oscillating shock wave. Based on a travelling wave ansatz for the fluid velocity potential with an added 2'nd order...... polynomial in the space and time variables, we find analytical approximations to the observed single shock waves in an infinitely long tube. Using perturbation theory for the driven acoustic system approximative analytical solutions for the off resonant case are determined....

  1. DIFFUSIVE SHOCK ACCELERATION AT COSMOLOGICAL SHOCK WAVES

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyesung [Department of Earth Sciences, Pusan National University, Pusan 609-735 (Korea, Republic of); Ryu, Dongsu, E-mail: kang@uju.es.pusan.ac.kr, E-mail: ryu@canopus.cnu.ac.kr [Department of Astronomy and Space Science, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2013-02-10

    We reexamine nonlinear diffusive shock acceleration (DSA) at cosmological shocks in the large-scale structure of the universe, incorporating wave-particle interactions that are expected to operate in collisionless shocks. Adopting simple phenomenological models for magnetic field amplification (MFA) by cosmic-ray (CR) streaming instabilities and Alfvenic drift, we perform kinetic DSA simulations for a wide range of sonic and Alfvenic Mach numbers and evaluate the CR injection fraction and acceleration efficiency. In our DSA model, the CR acceleration efficiency is determined mainly by the sonic Mach number M{sub s} , while the MFA factor depends on the Alfvenic Mach number and the degree of shock modification by CRs. We show that at strong CR modified shocks, if scattering centers drift with an effective Alfven speed in the amplified magnetic field, the CR energy spectrum is steepened and the acceleration efficiency is reduced significantly, compared to the cases without such effects. As a result, the postshock CR pressure saturates roughly at {approx}20% of the shock ram pressure for strong shocks with M{sub s} {approx}> 10. In the test-particle regime (M{sub s} {approx}< 3), it is expected that the magnetic field is not amplified and the Alfvenic drift effects are insignificant, although relevant plasma physical processes at low Mach number shocks remain largely uncertain.

  2. 30th International Symposium on Shock Waves

    CERN Document Server

    Sadot, Oren; Igra, Ozer

    2017-01-01

    These proceedings collect the papers presented at the 30th International Symposium on Shock Waves (ISSW30), which was held in Tel-Aviv Israel from July 19 to July 24, 2015. The Symposium was organized by Ortra Ltd. The ISSW30 focused on the state of knowledge of the following areas: Nozzle Flow, Supersonic and Hypersonic Flows with Shocks, Supersonic Jets, Chemical Kinetics, Chemical Reacting Flows, Detonation, Combustion, Ignition, Shock Wave Reflection and Interaction, Shock Wave Interaction with Obstacles, Shock Wave Interaction with Porous Media, Shock Wave Interaction with Granular Media, Shock Wave Interaction with Dusty Media, Plasma, Magnetohyrdrodynamics, Re-entry to Earth Atmosphere, Shock Waves in Rarefied Gases, Shock Waves in Condensed Matter (Solids and Liquids), Shock Waves in Dense Gases, Shock Wave Focusing, Richtmyer-Meshkov Instability, Shock Boundary Layer Interaction, Multiphase Flow, Blast Waves, Facilities, Flow Visualization, and Numerical Methods. The two volumes serve as a reference ...

  3. Shock experiments and numerical simulations on low energy portable electrically exploding foil accelerators.

    Science.gov (United States)

    Saxena, A K; Kaushik, T C; Gupta, Satish C

    2010-03-01

    Two low energy (1.6 and 8 kJ) portable electrically exploding foil accelerators are developed for moderately high pressure shock studies at small laboratory scale. Projectile velocities up to 4.0 km/s have been measured on Kapton flyers of thickness 125 microm and diameter 8 mm, using an in-house developed Fabry-Perot velocimeter. An asymmetric tilt of typically few milliradians has been measured in flyers using fiber optic technique. High pressure impact experiments have been carried out on tantalum, and aluminum targets up to pressures of 27 and 18 GPa, respectively. Peak particle velocities at the target-glass interface as measured by Fabry-Perot velocimeter have been found in good agreement with the reported equation of state data. A one-dimensional hydrodynamic code based on realistic models of equation of state and electrical resistivity has been developed to numerically simulate the flyer velocity profiles. The developed numerical scheme is validated against experimental and simulation data reported in literature on such systems. Numerically computed flyer velocity profiles and final flyer velocities have been found in close agreement with the previously reported experimental results with a significant improvement over reported magnetohydrodynamic simulations. Numerical modeling of low energy systems reported here predicts flyer velocity profiles higher than experimental values, indicating possibility of further improvement to achieve higher shock pressures.

  4. Flow behind concave shock waves

    Science.gov (United States)

    Mölder, S.

    2017-03-01

    Curved shock theory is introduced and applied to calculate the flow behind concave shock waves. For sonic conditions, three characterizing types of flow are identified, based on the orientation of the sonic line, and it is shown that, depending on the ratio of shock curvatures, a continuously curving shock can exist with Type III flow, where the sonic line intercepts the reflected characteristics from the shock, thus preventing the formation of a reflected shock. The necessary shock curvature ratio for a Type III sonic point does not exist for a hyperbolic shock so that it will revert to Mach reflection for all Mach numbers. A demonstration is provided, by CFD calculations, at Mach 1.2 and 3.

  5. Flow behind concave shock waves

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Curved shock theory is introduced and applied to calculate the flow behind concave shock waves. For sonic conditions, three characterizing types of flow are identified, based on the orientation of the sonic line, and it is shown that, depending on the ratio of shock curvatures, a continuously curving shock can exist with Type III flow, where the sonic line intercepts the reflected characteristics from the shock, thus preventing the formation of a reflected shock. The necessary shock curvature ratio for a Type III sonic point does not exist for a hyperbolic shock so that it will revert to Mach reflection for all Mach numbers. A demonstration is provided, by CFD calculations, at Mach 1.2 and 3.

  6. INTERFERENCE OF COUNTERPROPAGATING SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-03-01

    Full Text Available The subject of study. We examined the interaction of counterpropagating shock waves. The necessity of counterpropagating shock waves studying occurs at designing of high Mach number modern internal compression air intakes, Ramjets with subsonic and supersonic combustion, in asymmetrical supersonic nozzles and in some other cases. In a sense, this problem is a generalization of the case of an oblique shock reflection from the wall or from the plane of symmetry. With the renewed vigor, the interest to this problem emerged at the end of the 90s. This was due to the start of the programs for flight study at hypersonic speeds. The first experiments performed with air intakes, which realized the interaction of counterpropagating shock waves have shown that the change in flow velocity is accompanied by abrupt alteration of shock-wave structure, the occurrence of nonstationary and oscillatory phenomena. With an increase of flow velocity these phenomena undesirable for aircraft structure became more marked. The reason is that there are two fundamentally different modes of interaction of counterpropagating shock waves: a four-wave regular and a five-wave irregular. The transition from one mode to another can be nonstationary abrupt or gradual, it can also be accompanied by hysteresis. Main results. Criteria for the transition from regular reflection of counterpropagating shock waves to irregular are described: the criterion of von Neumann and the stationary Mach configuration criterion. We described areas in which the transition from one reflection type to another is possible only in abrupt way, as well as areas of possible gradual transition. Intensity dependences of the reflected shock waves from the intensity of interacting counterpropagating shocks were given. Qualitative pictures of shock-wave structures arising from the interaction of counterpropagating shock waves were shown. Calculation results of the intensity of outgoing gas

  7. Shock waves in disordered media

    CERN Document Server

    Ghofraniha, N; Folli, V; DelRe, E; Conti, C

    2012-01-01

    We experimentally investigate the interplay between spatial shock waves and the degree of disorder during nonlinear optical propagation in a thermal defocusing medium. We characterize the way the shock point is affected by the amount of disorder and scales with wave amplitude. Evidence for the existence of a phase diagram in terms of nonlinearity and amount of randomness is reported. The results are in quantitative agreement with a theoretical approach based on the hydrodynamic approximation.

  8. Cosmology with a shock wave

    OpenAIRE

    1998-01-01

    We construct the simplest solution of the Einstein equations that incorporates a shock-wave into a standard Friedmann-Robertson-Walker metric whose equation of state accounts for the Hubble constant and the microwave background radiation temperature. This produces a new solution of the Einstein equations from which we are able to derive estimates for the shock position at present time. We show that the distance from the shock-wave to the center of the explosion at present time is comparable t...

  9. Diffusive Shock Acceleration at Cosmological Shock Waves

    CERN Document Server

    Kang, Hyesung

    2012-01-01

    We reexamine nonlinear diffusive shock acceleration (DSA) at cosmological shocks in the large scale structure of the Universe, incorporating wave-particle interactions that are expected to operate in collisionless shocks. Adopting simple phenomenological models for magnetic field amplification (MFA) by cosmic-ray (CR) streaming instabilities and Alfv'enic drift, we perform kinetic DSA simulations for a wide range of sonic and Alfv'enic Mach numbers and evaluate the CR injection fraction and acceleration efficiency. In our DSA model the CR acceleration efficiency is determined mainly by the sonic Mach number Ms, while the MFA factor depends on the Alfv'enic Mach number and the degree of shock modification by CRs. We show that at strong CR modified shocks, if scattering centers drift with an effective Alfv'en speed in the amplified magnetic field, the CR energy spectrum is steepened and the acceleration efficiency is reduced significantly, compared to the cases without such effects. As a result, the postshock C...

  10. Shock waves in polycrystalline iron.

    Science.gov (United States)

    Kadau, Kai; Germann, Timothy C; Lomdahl, Peter S; Albers, Robert C; Wark, Justin S; Higginbotham, Andrew; Holian, Brad Lee

    2007-03-30

    The propagation of shock waves through polycrystalline iron is explored by large-scale atomistic simulations. For large enough shock strengths the passage of the wave causes the body-centered-cubic phase to transform into a close-packed phase with most structure being isotropic hexagonal-close-packed (hcp) and, depending on shock strength and grain orientation, some fraction of face-centered-cubic (fcc) structure. The simulated shock Hugoniot is compared to experiments. By calculating the extended x-ray absorption fine structure (EXAFS) directly from the atomic configurations, a comparison to experimental EXAFS measurements of nanosecond-laser shocks shows that the experimental data is consistent with such a phase transformation. However, the atomistically simulated EXAFS spectra also show that an experimental distinction between the hcp or fcc phase is not possible based on the spectra alone.

  11. Shock wave-droplet interaction

    Science.gov (United States)

    Habibi Khoshmehr, Hamed; Krechetnikov, Rouslan

    2016-11-01

    Disintegration of a liquid droplet under the action of a shock wave is experimentally investigated. The shock wave-pulse is electromagnetically generated by discharging a high voltage capacitor into a flat spiral coil, above which an isolated circular metal membrane is placed in a close proximity. The Lorentz force arising due to the eddy current induced in the membrane abruptly accelerates it away from the spiral coil thus generating a shock wave. The liquid droplet placed at the center of the membrane, where the maximum deflection occurs, is disintegrated in the process of interaction with the shock wave. The effects of droplet viscosity and surface tension on the droplet destruction are studied with high-speed photography. Water-glycerol solution at different concentrations is used for investigating the effect of viscosity and various concentrations of water-sugar and water-ethanol solution are used for studying the effect of surface tension. Here we report on how the metamorphoses, which a liquid drop undergoes in the process of interaction with a shock wave, are affected by varied viscosity and surface tension.

  12. Cavitation inception following shock wave passage

    NARCIS (Netherlands)

    Ohl, C.D.

    2002-01-01

    Cavitation bubble nucleation following the passage of an extracorporeal shock wave lithotripter pulse is investigated experimentally and numerically. In the experiments two configurations are considered: Free passage of the shock wave, and reflection of the shock wave from a rigid reflector. The nuc

  13. Cavitation inception following shock wave passage

    NARCIS (Netherlands)

    Ohl, C.D.

    2002-01-01

    Cavitation bubble nucleation following the passage of an extracorporeal shock wave lithotripter pulse is investigated experimentally and numerically. In the experiments two configurations are considered: Free passage of the shock wave, and reflection of the shock wave from a rigid reflector. The nuc

  14. Low Energy Multi-Stage Atrial Defibrillation Therapy Terminates Atrial Fibrillation with Less Energy than a Single Shock

    Science.gov (United States)

    Li, Wenwen; Janardhan, Ajit H.; Fedorov, Vadim V.; Sha, Qun; Schuessler, Richard B.; Efimov, Igor R.

    2011-01-01

    Background Implantable device therapy of atrial fibrillation (AF) is limited by pain from high-energy shocks. We developed a low-energy multi-stage defibrillation therapy and tested it in a canine model of AF. Methods and Results AF was induced by burst pacing during vagus nerve stimulation. Our novel defibrillation therapy consisted of three stages: ST1 (1-4 low energy biphasic shocks), ST2 (6-10 ultra-low energy monophasic shocks), and ST3 (anti-tachycardia pacing). Firstly, ST1 testing compared single or multiple monophasic (MP) and biphasic (BP) shocks. Secondly, several multi-stage therapies were tested: ST1 versus ST1+ST3 versus ST1+ST2+ST3. Thirdly, three shock vectors were compared: superior vena cava to distal coronary sinus (SVC>CSd), proximal coronary sinus to left atrial appendage (CSp>LAA) and right atrial appendage to left atrial appendage (RAA>LAA). The atrial defibrillation threshold (DFT) of 1BP shock was less than 1MP shock (0.55 ± 0.1 versus 1.38 ± 0.31 J; p =0.003). 2-3 BP shocks terminated AF with lower peak voltage than 1BP or 1MP shock and with lower atrial DFT than 4 BP shocks. Compared to ST1 therapy alone, ST1+ST3 lowered the atrial DFT moderately (0.51 ± 0.46 versus 0.95 ± 0.32 J; p = 0.036) while a three-stage therapy, ST1+ST2+ST3, dramatically lowered the atrial DFT (0.19 ± 0.12 J versus 0.95 ± 0.32 J for ST1 alone, p=0.0012). Finally, the three-stage therapy ST1+ST2+ST3 was equally effective for all studied vectors. Conclusions Three-stage electrotherapy significantly reduces the AF defibrillation threshold and opens the door to low energy atrial defibrillation at or below the pain threshold. PMID:21980076

  15. Model for Shock Wave Chaos

    KAUST Repository

    Kasimov, Aslan R.

    2013-03-08

    We propose the following model equation, ut+1/2(u2−uus)x=f(x,us) that predicts chaotic shock waves, similar to those in detonations in chemically reacting mixtures. The equation is given on the half line, x<0, and the shock is located at x=0 for any t≥0. Here, us(t) is the shock state and the source term f is taken to mimic the chemical energy release in detonations. This equation retains the essential physics needed to reproduce many properties of detonations in gaseous reactive mixtures: steady traveling wave solutions, instability of such solutions, and the onset of chaos. Our model is the first (to our knowledge) to describe chaos in shock waves by a scalar first-order partial differential equation. The chaos arises in the equation thanks to an interplay between the nonlinearity of the inviscid Burgers equation and a novel forcing term that is nonlocal in nature and has deep physical roots in reactive Euler equations.

  16. Isothermal Shock Wave in Magnetogasdynamics

    Directory of Open Access Journals (Sweden)

    B. G. Verma

    1983-01-01

    Full Text Available The problem of propagation of a plane isothermal discontinuity (shock wave in a homogeneous semi-infinite body of a perfect gas, in the presence of amagnetic field have been solved. It has been shown that under certain definiteconditions, the density p at the wave front may be arbitrarily high for a singlecompression pulse. A certain class of solutions of the present problem for a nonhomogeneous semi-infinite body have been derived. Such solutions are expected to be of great importance in compression problems of plasma.

  17. 29th International Symposium on Shock Waves

    CERN Document Server

    Ranjan, Devesh

    2015-01-01

    This proceedings present the results of the 29th International Symposium on Shock Waves (ISSW29) which was held in Madison, Wisconsin, U.S.A., from July 14 to July 19, 2013. It was organized by the Wisconsin Shock Tube Laboratory, which is part of the College of Engineering of the University of Wisconsin-Madison. The ISSW29 focused on the following areas: Blast Waves, Chemically Reactive Flows, Detonation and Combustion,  Facilities, Flow Visualization, Hypersonic Flow, Ignition, Impact and Compaction, Industrial Applications, Magnetohydrodynamics, Medical and Biological Applications, Nozzle Flow, Numerical Methods, Plasmas, Propulsion, Richtmyer-Meshkov Instability, Shock-Boundary Layer Interaction, Shock Propagation and Reflection, Shock Vortex Interaction, Shock Waves in Condensed Matter, Shock Waves in Multiphase Flow, as well as Shock Waves in Rarefield Flow. The two Volumes contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 29 and individuals interes...

  18. Magnetic Fields inside Extremely Fast Shock Waves

    NARCIS (Netherlands)

    Wiersma, J.

    2007-01-01

    The aim of my research on magnetic fields in extremely fast shock waves has been to predict the properties of shock waves that move almost with the speed of light. These shocks are created in the tenuous interstellar medium by catastrophic events such as the explosion of stars many times heavier

  19. Magnetic Fields inside Extremely Fast Shock Waves

    NARCIS (Netherlands)

    Wiersma, J.

    2007-01-01

    The aim of my research on magnetic fields in extremely fast shock waves has been to predict the properties of shock waves that move almost with the speed of light. These shocks are created in the tenuous interstellar medium by catastrophic events such as the explosion of stars many times heavier

  20. Experimental methods of shock wave research

    CERN Document Server

    Seiler, Friedrich

    2016-01-01

    This comprehensive and carefully edited volume presents a variety of experimental methods used in Shock Waves research. In 14 self contained chapters this 9th volume of the “Shock Wave Science and Technology Reference Library” presents the experimental methods used in Shock Tubes, Shock Tunnels and Expansion Tubes facilities. Also described is their set-up and operation. The uses of an arc heated wind tunnel and a gun tunnel are also contained in this volume. Whenever possible, in addition to the technical description some typical scientific results obtained using such facilities are described. Additionally, this authoritative book includes techniques for measuring physical properties of blast waves and laser generated shock waves. Information about active shock wave laboratories at different locations around the world that are not described in the chapters herein is given in the Appendix, making this book useful for every researcher involved in shock/blast wave phenomena.

  1. Stationary one-dimensional dispersive shock waves

    CERN Document Server

    Kartashov, Yaroslav V

    2011-01-01

    We address shock waves generated upon the interaction of tilted plane waves with negative refractive index defect in defocusing media with linear gain and two-photon absorption. We found that in contrast to conservative media where one-dimensional dispersive shock waves usually exist only as nonstationary objects expanding away from defect or generating beam, the competition between gain and two-photon absorption in dissipative medium results in the formation of localized stationary dispersive shock waves, whose transverse extent may considerably exceed that of the refractive index defect. One-dimensional dispersive shock waves are stable if the defect strength does not exceed certain critical value.

  2. Detonation onset following shock wave focusing

    Science.gov (United States)

    Smirnov, N. N.; Penyazkov, O. G.; Sevrouk, K. L.; Nikitin, V. F.; Stamov, L. I.; Tyurenkova, V. V.

    2017-06-01

    The aim of the present paper is to study detonation initiation due to focusing of a shock wave reflected inside a cone. Both numerical and experimental investigations were conducted. Comparison of results made it possible to validate the developed 3-d transient mathematical model of chemically reacting gas mixture flows incorporating hydrogen - air mixtures. The results of theoretical and numerical experiments made it possible improving kinetic schemes and turbulence models. Several different flow scenarios were detected in reflection of shock waves all being dependent on incident shock wave intensity: reflecting of shock wave with lagging behind combustion zone, formation of detonation wave in reflection and focusing, and intermediate transient regimes.

  3. SHOCK WAVE IN IONOSPHERE DURING EARTHQUAKE

    Directory of Open Access Journals (Sweden)

    V.V. Kuznetsov

    2016-11-01

    Full Text Available Fundamentally new model of the shock wave (SW generation in atmosphere and ionosphere during earthquake is proposed. The model proceeds from the idea of cooperative shock water crystallization in a cloud

  4. Waves near interplanetary shocks observed by STEREO

    Science.gov (United States)

    Aguilar-Rodriguez, E.; Blanco-Cano, X.; Russell, C. T.; Luhmann, J. G.; Krauss-Varban, D.

    2007-12-01

    We investigate the properties of interplanetary shocks that form ahead of virtually all fast propagating coronal mass ejections (CMEs). Understanding the characteristics of these shocks and their surrounding regions is of great interest as they play a major role in the acceleration of solar energetic particles (SEPs). In this work we study low frequency waves upstream and downstream of interplanetary shocks (IP) observed by the twin spacecraft mission STEREO. In the upstream region waves can be generated by ion beams reflected or otherwise energized at the shock. Downstream the wave spectrum may be formed by both, waves generated locally and waves transmitted through the shock.The efficiency of wave generation and wave convection to the shock depends on the shock Mach number, and the angle between the IMF and the shock normal. Waves can disturb the shock and participate in ion acceleration processes. Multi-point STEREO measurements will allow us to study wave characteristics in different regions near IP shocks and determine the effects that these fluctuations have on particle energization.

  5. Corrugation of relativistic magnetized shock waves

    CERN Document Server

    Lemoine, M; Gremillet, L

    2016-01-01

    As a shock front interacts with turbulence, it develops corrugation which induces outgoing wave modes in the downstream plasma. For a fast shock wave, the incoming wave modes can either be fast magnetosonic waves originating from downstream, outrunning the shock, or eigenmodes of the upstream plasma drifting through the shock. Using linear perturbation theory in relativistic MHD, this paper provides a general analysis of the corrugation of relativistic magnetized fast shock waves resulting from their interaction with small amplitude disturbances. Transfer functions characterizing the linear response for each of the outgoing modes are calculated as a function of the magnetization of the upstream medium and as a function of the nature of the incoming wave. Interestingly, if the latter is an eigenmode of the upstream plasma, we find that there exists a resonance at which the (linear) response of the shock becomes large or even diverges. This result may have profound consequences on the phenomenology of astrophys...

  6. Complexity and Shock Wave Geometries

    CERN Document Server

    Stanford, Douglas

    2014-01-01

    In this paper we refine a conjecture relating the time-dependent size of an Einstein-Rosen bridge to the computational complexity of the of the dual quantum state. Our refinement states that the complexity is proportional to the spatial volume of the ERB. More precisely, up to an ambiguous numerical coefficient, we propose that the complexity is the regularized volume of the largest codimension one surface crossing the bridge, divided by $G_N l_{AdS}$. We test this conjecture against a wide variety of spherically symmetric shock wave geometries in different dimensions. We find detailed agreement.

  7. EFFECT OF SHOCK WAVES ON RILL FORMATION

    Institute of Scientific and Technical Information of China (English)

    Keli ZHANG; Lifang LUO; Shuangcai LI

    2004-01-01

    Hydraulic mechanism of rill formation was studied theoretically and experimentally.It was assumed that the impact of varied boundary on overland flow results in fluctuating of water surface,and shock waves that may contribute to the formation of rills.Both theoretical derivation and laboratory experiments were used to compare the hydraulic characteristics of flows with and without shock waves.Results showed that shock waves can lead to an increase in flowdepth,flow velocity,and turbulence intensity.Consequently,flow shear stress or stream energy increase dramatically and rill headcuts may occur where shock waves converge.

  8. Shock Wave Smearing by Passive Control

    Institute of Scientific and Technical Information of China (English)

    Piotr DOERFFER; Oskar SZULC; Rainer BOHNING

    2006-01-01

    Normal shock wave, terminating a local supersonic area on an airfoil, limits its performance and becomes a source of high speed impulsive noise. It is proposed to use passive control to disintegrate the shock wave. Details of the flow structure obtained by this method are studied numerically. A new boundary condition has been developed and the results of its application are verified against experiments in a nozzle flow. The method of shock wave disintegration has been confirmed and detailed analysis of the flow details is presented. The substitution of a shock wave by a gradual compression changes completely the source of the high speed impulsive noise and bears potential of its reduction.

  9. The microphysics of collisionless shock waves

    CERN Document Server

    Marcowith, A; Bykov, A; Dieckman, M E; Drury, L O C; Lembege, B; Lemoine, M; Morlino, G; Murphy, G; Pelletier, G; Plotnikov, I; Reville, B; Riquelme, M; Sironi, L; Novo, A Stockem

    2016-01-01

    Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebul\\ae, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space. It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in-situ observations, analytical and numerical developments. A particular emphasize is made on the different instabilities triggered during the shock formation and in a...

  10. Nonlinear saturation of wave packets excited by low-energy electron horseshoe distributions.

    Science.gov (United States)

    Krafft, C; Volokitin, A

    2013-05-01

    Horseshoe distributions are shell-like particle distributions that can arise in space and laboratory plasmas when particle beams propagate into increasing magnetic fields. The present paper studies the stability and the dynamics of wave packets interacting resonantly with electrons presenting low-energy horseshoe or shell-type velocity distributions in a magnetized plasma. The linear instability growth rates are determined as a function of the ratio of the plasma to the cyclotron frequencies, of the velocity and the opening angle of the horseshoe, and of the relative thickness of the shell. The nonlinear stage of the instability is investigated numerically using a symplectic code based on a three-dimensional Hamiltonian model. Simulation results show that the dynamics of the system is mainly governed by wave-particle interactions at Landau and normal cyclotron resonances and that the high-order normal cyclotron resonances play an essential role. Specific features of the dynamics of particles interacting simultaneously with two or more waves at resonances of different natures and orders are discussed, showing that such complex processes determine the main characteristics of the wave spectrum's evolution. Simulations with wave packets presenting quasicontinuous spectra provide a full picture of the relaxation of the horseshoe distribution, revealing two main phases of the evolution: an initial stage of wave energy growth, characterized by a fast filling of the shell, and a second phase of slow damping of the wave energy, accompanied by final adjustments of the electron distribution. The influence of the density inhomogeneity along the horseshoe on the wave-particle dynamics is also discussed.

  11. The microphysics of collisionless shock waves

    DEFF Research Database (Denmark)

    Marcowith, Alexandre; Bret, Antoine; Bykov, Andrei

    2016-01-01

    galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space...... the magnetization and its obliquity is the dominant one. The shock velocity that can reach relativistic speeds has also a strong impact over the development of the micro-instabilities and the fate of particle acceleration. Recent developments of laboratory shock experiments has started to bring some new insights...... in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics....

  12. Whistler Waves Associated with Weak Interplanetary Shocks

    Science.gov (United States)

    Velez, J. C. Ramirez; Blanco-Cano, X.; Aguilar-Rodriguez, E.; Russell, C. T.; Kajdic, P.; Jian,, L. K.; Luhmann, J. G.

    2012-01-01

    We analyze the properties of 98 weak interplanetary shocks measured by the dual STEREO spacecraft over approximately 3 years during the past solar minimum. We study the occurrence of whistler waves associated with these shocks, which on average are high beta shocks (0.2 whistler waves can extend up to 100,000 km in the upstream region but in most cases (88%) are contained in a distance within 30,000 km from the shock. This corresponds to a larger region with upstream whistlers associated with IP shocks than previously reported in the literature. The maximum amplitudes of the waves are observed next to the shock interface, and they decrease as the distance to the shock increases. In most cases the wave propagation direction becomes more aligned with the magnetic field as the distance to the shock increases. These two facts suggest that most of the waves in the upstream region are Landau damping as they move away from the shock. From the analysis we also conclude that it is likely that the generation mechanism of the upstream whistler waves is taking place at the shock interface. In the downstream region, the waves are irregularly polarized, and the fluctuations are very compressive; that is, the compressive component of the wave clearly dominates over the transverse one. The majority of waves in the downstream region (95%) propagate at oblique angles with respect to the ambient magnetic field (>60 deg.). The wave propagation with respect to the shock-normal direction has no preferred direction and varies similarly to the upstream case. It is possible that downstream fluctuations are generated by ion relaxation as suggested in previous hybrid simulation shocks.

  13. Physics of Collisionless Shocks Space Plasma Shock Waves

    CERN Document Server

    Balogh, André

    2013-01-01

    The present book provides a contemporary systematic treatment of shock waves in high-temperature collisionless plasmas as are encountered in near Earth space and in Astrophysics. It consists of two parts. Part I develops the complete theory of shocks in dilute hot plasmas under the assumption of absence of collisions among the charged particles when the interaction is mediated solely by the self-consistent electromagnetic fields. Such shocks are naturally magnetised implying that the magnetic field plays an important role in their evolution and dynamics. This part treats both subcritical shocks, which dissipate flow energy by generating anomalous resistance or viscosity, and supercritical shocks. The main emphasis is, however, on super-critical shocks where the anomalous dissipation is insufficient to retard the upstream flow. These shocks, depending on the direction of the upstream magnetic field, are distinguished as quasi-perpendicular and quasi-parallel shocks which exhibit different behaviours, reflecti...

  14. Topics on shock waves and coronal seismology

    Energy Technology Data Exchange (ETDEWEB)

    Costa, A, E-mail: acosta@mail.oac.uncor.edu [Instituto de AstronomIa Teorica y Experimental, CONICET-Cordoba, Laprida 922, 5000 Cordoba (Argentina); Facultad de Ciencias Exactas, Fisica y Naturales, Universidad Nacional de Cordoba, Av. Velez Sarsfield 1611, 5000 Cordoba (Argentina)

    2011-07-15

    The usual strong and sudden energy release sources that necessarily lead to mode excitation suggest the importance of shocks and nonlinear waves in the corona. We discuss the importance of nonlinear waves as an alternative capable of accurately matching the observational cases of coronal seismology usually interpreted as linear waves. We present two case studies where we explore the goodness of the shock wave interpretation in magnetic structures of the low corona.

  15. The microphysics of collisionless shock waves

    DEFF Research Database (Denmark)

    Marcowith, Alexandre; Bret, Antoine; Bykov, Andrei;

    2016-01-01

    Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active...... galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space....... It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in situ observations, analytical and numerical developments...

  16. Introduction to Shock Waves and Shock Wave Research

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, William Wyatt [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    M-9 and a number of other organizations at LANL and elsewhere study materials in dynamic processes. Often, this is described as “shock wave research,” but in reality is broader than is implied by that term. Most of our work is focused on dynamic compression and associated phenomena, but you will find a wide variety of things we do that, while related, are not simple compression of materials, but involve a much richer variety of phenomena. This tutorial will introduce some of the underlying physics involved in this work, some of the more common types of phenomena we study, and common techniques. However, the list will not be exhaustive by any means.

  17. [Shock wave treatment for tennis elbow].

    Science.gov (United States)

    Rompe, J D; Theis, C; Maffulli, N

    2005-06-01

    Randomized controlled trials were evaluated to assess the effectiveness of extracorporeal shock wave treatment in the management of tennis elbow. Five trials had a mediocre methodology and four trials had a high-quality design. Well-designed randomized control trials have provided evidence of the effectiveness of shock wave intervention for tennis elbow.

  18. Shock wave interactions with liquid sheets

    Science.gov (United States)

    Jeon, H.; Eliasson, V.

    2017-04-01

    Shock wave interactions with a liquid sheet are investigated by impacting planar liquid sheets of varying thicknesses with a planar shock wave. A square frame was designed to hold a rectangular liquid sheet, with a thickness of 5 or 10 mm, using plastic membranes and cotton wires to maintain the planar shape and minimize bulge. The flat liquid sheet, consisting of either water or a cornstarch and water mixture, was suspended in the test section of a shock tube. Incident shock waves with Mach numbers of M_s = 1.34 and 1.46 were considered. A schlieren technique with a high-speed camera was used to visualize the shock wave interaction with the liquid sheets. High-frequency pressure sensors were used to measure wave speed, overpressure, and impulse both upstream and downstream of the liquid sheet. Results showed that no transmitted shock wave could be observed through the liquid sheets, but compression waves induced by the shock-accelerated liquid coalesced into a shock wave farther downstream. A thicker liquid sheet resulted in a lower peak overpressure and impulse, and a cornstarch suspension sheet showed a higher attenuation factor compared to a water sheet.

  19. Numerical simulation of converging shock waves

    Science.gov (United States)

    Yee, Seokjune; Abe, Kanji

    We can achieve the high pressure and high temperature state of gas if the shock wave converges stably. In order to check the stability of the converging shock wave, we introduce two kinds of perturbed initial conditions. The Euler equations of conservation form are integrated by using explicit Non-Muscl TVD finite difference scheme.

  20. Investigation on stability of electrohydrodynamic shock waves

    Directory of Open Access Journals (Sweden)

    A. M. Blokhin

    1997-05-01

    Full Text Available Well-posedness of a linear mixed problem on stability of electrohydrodynamic shock waves is investigated in the paper. Stability of shock waves for a hydrodynamic model of movement of a continuum with a volume electric charge is proved.

  1. Sulphur hexaflouride: low energy (e,2e) experiments and molecular three-body distorted wave theory

    Science.gov (United States)

    Nixon, Kate L.; Murray, Andrew J.; Chaluvadi, H.; Ning, C. G.; Colgan, James; Madison, Don H.

    2016-10-01

    Experimental and theoretical triple differential ionisation cross-sections (TDCSs) are presented for the highest occupied molecular orbital of sulphur hexafluoride. These measurements were performed in the low energy regime, with outgoing electron energies ranging from 5 to 40 eV in a coplanar geometry, and with energies of 10 and 20 eV in a perpendicular geometry. Complementary theoretical predictions of the TDCS were calculated using the molecular three-body distorted wave formalism. Calculations were performed using a proper average over molecular orientations as well as the orientation-averaged molecular orbital approximation. This more sophisticated model was found to be in closer agreement with the experimental data, however neither model accurately predicts the TDCS over all geometries and energies.

  2. Reflection of curved shock waves

    Science.gov (United States)

    Mölder, S.

    2017-03-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  3. Reflection of curved shock waves

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  4. Shock waves on complex networks

    CERN Document Server

    Mones, Enys; Vicsek, Tamás; Herrmann, Hans J

    2014-01-01

    Power grids, road maps, and river streams are examples of infrastructural networks which are highly vulnerable to external perturbations. An abrupt local change of load (voltage, traffic density, or water level) might propagate in a cascading way and affect a significant fraction of the network. Almost discontinuous perturbations can be modeled by shock waves which can eventually interfere constructively and endanger the normal functionality of the infrastructure. We study their dynamics by solving the Burgers equation under random perturbations on several real and artificial directed graphs. Even for graphs with a narrow distribution of node properties (e.g., degree or betweenness), a steady state is reached exhibiting a heterogeneous load distribution, having a difference of one order of magnitude between the highest and average loads. Unexpectedly we find for the European power grid and for finite Watts-Strogatz networks a broad pronounced bimodal distribution for the loads. To identify the most vulnerable...

  5. Shock wave velocity and shock pressure for low density powders : A novel approach

    NARCIS (Netherlands)

    Dijken, D.K.; Hosson, J.Th.M. De

    1994-01-01

    A novel approach is presented to predict the shock wave velocity as well as the shock wave pressure in powder materials. It is shown that the influence of the specific volume behind the shock wave on shock wave velocity and shock pressure decreases with decreasing initial powder density. The new mod

  6. SHOCK-WAVE VELOCITY AND SHOCK PRESSURE FOR LOW-DENSITY POWDERS - A NOVEL-APPROACH

    NARCIS (Netherlands)

    DIJKEN, DK; DEHOSSON, JTM

    1994-01-01

    A novel approach is presented to predict the shock wave velocity as well as the shock wave pressure in powder materials. It is shown that the influence of the specific volume behind the shock wave on shock wave velocity and shock pressure decreases with decreasing initial powder density. The new mod

  7. Shock Wave Dynamics in Weakly Ionized Plasmas

    Science.gov (United States)

    Johnson, Joseph A., III

    1999-01-01

    An investigation of the dynamics of shock waves in weakly ionized argon plasmas has been performed using a pressure ruptured shock tube. The velocity of the shock is observed to increase when the shock traverses the plasma. The observed increases cannot be accounted for by thermal effects alone. Possible mechanisms that could explain the anomalous behavior include a vibrational/translational relaxation in the nonequilibrium plasma, electron diffusion across the shock front resulting from high electron mobility, and the propagation of ion-acoustic waves generated at the shock front. Using a turbulence model based on reduced kinetic theory, analysis of the observed results suggest a role for turbulence in anomalous shock dynamics in weakly ionized media and plasma-induced hypersonic drag reduction.

  8. 28th International Symposium on Shock Waves

    CERN Document Server

    2012-01-01

    The University of Manchester hosted the 28th International Symposium on Shock Waves between 17 and 22 July 2011. The International Symposium on Shock Waves first took place in 1957 in Boston and has since become an internationally acclaimed series of meetings for the wider Shock Wave Community. The ISSW28 focused on the following areas: Blast Waves, Chemically Reacting Flows, Dense Gases and Rarefied Flows, Detonation and Combustion, Diagnostics, Facilities, Flow Visualisation, Hypersonic Flow, Ignition, Impact and Compaction, Multiphase Flow, Nozzle Flow, Numerical Methods, Propulsion, Richtmyer-Meshkov, Shockwave Boundary Layer Interaction, Shock Propagation and Reflection, Shock Vortex Interaction, Shockwave Phenomena and Applications, as well as Medical and Biological Applications. The two Volumes contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 28 and individuals interested in these fields.

  9. Shock Wave Emissions of a Sonoluminescing Bubble

    CERN Document Server

    Holzfuss, J; Billó, M; Holzfuss, Joachim; Ruggeberg, Matthias; Billo, Andreas

    1998-01-01

    A single bubble in water is excited by a standing ultrasound wave. At high intensity the bubble starts to emit light. Together with the emitted light pulse, a shock wave is generated in the liquid at collapse time. The time-dependent velocity of the outward-travelling shock is measured with an imaging technique. The pressure in the shock and in the bubble is shown to have a lower limit of 5500 bars. Visualization of the shock and the bubble at different phases of the acoustic cycle reveals previously unobserved dynamics during stable and unstable sonoluminescence.

  10. Overview of shock waves in medicine

    Science.gov (United States)

    Cleveland, Robin O.

    2003-10-01

    A brief overview of three applications of shock waves is presented. Shock wave lithotripsy (SWL) has been in clinical use for more than 20 years. In the United States it is used to treat more than 80% of kidney stone cases and has wide acceptance with patients because it is a noninvasive procedure. Despite SWLs enormous success there is no agreement on how shock waves comminute stones. There is also a general acceptance that shock waves lead to trauma to the soft tissue of the kidney. Yet there has been little forward progress in developing lithotripters which provide comminution with less side-effects, indeed the original machine is still considered the gold standard. The last decade has seen the advent of new shock wave devices for treating principally musculoskeletal indications, such as plantar fasciitis, tennis elbow, and bone fractures that do not heal. This is referred to as shock wave therapy (SWT). The mechanisms by which SWT works are even less well understood than SWL and the consequences of bioeffects have also not been studied in detail. Shock waves have also been shown to be effective at enhancing drug delivery into cells and assisting with gene transfection. [Work partially supported by NIH.

  11. Shock wave structure in a lattice gas

    Science.gov (United States)

    Broadwell, James E.; Han, Donghee

    2007-05-01

    The motion and structure of shock and expansion waves in a simple particle system, a lattice gas and cellular automaton, are determined in an exact computation. Shock wave solutions, also exact, of a continuum description, a model Boltzmann equation, are compared with the lattice results. The comparison demonstrates that, as proved by Caprino et al. ["A derivation of the Broadwell equation," Commun. Math. Phys. 135, 443 (1991)] only when the lattice processes are stochastic is the model Boltzmann description accurate. In the strongest shock wave, the velocity distribution function is the bimodal function proposed by Mott-Smith.

  12. Shock wave dynamics derivatives and related topics

    CERN Document Server

    Emanuel, George

    2012-01-01

    Working knowledge of the relations of various quantities and their derivatives across a shock wave is useful for any advanced research involving shock waves. Although these relations can be derived in principle by any diligent student of the subject, the derivations are often not trivial, and once derived, neither the approach nor the result can be confidently verified. Comprehensive and analytical, Shock Wave Dynamics: Derivatives and Related Topics includes not only the final results but also the methods, which are of great practical value as examples of mathematical procedure in this field.

  13. Experimental investigation of shock wave - bubble interaction

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Mohsen

    2010-04-09

    In this work, the dynamics of laser-generated single cavitation bubbles exposed to lithotripter shock waves has been investigated experimentally. The energy of the impinging shock wave is varied in several steps. High-speed photography and pressure field measurements simultaneously with image acquisition provide the possibility of capturing the fast bubble dynamics under the effect of the shock wave impact. The pressure measurement is performed using a fiber optic probe hydrophone (FOPH) which operates based on optical diagnostics of the shock wave propagating medium. After a short introduction in chapter 1 an overview of the previous studies in chapter 2 is presented. The reported literatures include theoretical and experimental investigations of several configurations of physical problems in the field of bubble dynamics. In chapter 3 a theoretical description of propagation of a shock wave in a liquid like water has been discussed. Different kinds of reflection of a shock wave at an interface are taken into account. Undisturbed bubble dynamics as well as interaction between a planar shock wave and an initially spherical bubble are explored theoretically. Some physical parameters which are important in this issue such as the velocity of the shock-induced liquid jet, Kelvin impulse and kinetic energy are explained. The shock waves are generated in a water filled container by a focusing piezoelectric generator. The shock wave profile has a positive part with pulse duration of ∼1 μs followed by a longer tension tail (i.e. ∼3 μs). In chapter 4 high-speed images depict the propagation of a shock wave in the water filled tank. The maximum pressure is also derived for different intensity levels of the shock wave generator. The measurement is performed in the free field (i.e. in the absence of laser-generated single bubbles). In chapter 5 the interaction between lithotripter shock waves and laserinduced single cavitation bubbles is investigated experimentally. An

  14. Experimental investigation of shock wave - bubble interaction

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Mohsen

    2010-04-09

    In this work, the dynamics of laser-generated single cavitation bubbles exposed to lithotripter shock waves has been investigated experimentally. The energy of the impinging shock wave is varied in several steps. High-speed photography and pressure field measurements simultaneously with image acquisition provide the possibility of capturing the fast bubble dynamics under the effect of the shock wave impact. The pressure measurement is performed using a fiber optic probe hydrophone (FOPH) which operates based on optical diagnostics of the shock wave propagating medium. After a short introduction in chapter 1 an overview of the previous studies in chapter 2 is presented. The reported literatures include theoretical and experimental investigations of several configurations of physical problems in the field of bubble dynamics. In chapter 3 a theoretical description of propagation of a shock wave in a liquid like water has been discussed. Different kinds of reflection of a shock wave at an interface are taken into account. Undisturbed bubble dynamics as well as interaction between a planar shock wave and an initially spherical bubble are explored theoretically. Some physical parameters which are important in this issue such as the velocity of the shock-induced liquid jet, Kelvin impulse and kinetic energy are explained. The shock waves are generated in a water filled container by a focusing piezoelectric generator. The shock wave profile has a positive part with pulse duration of ∼1 μs followed by a longer tension tail (i.e. ∼3 μs). In chapter 4 high-speed images depict the propagation of a shock wave in the water filled tank. The maximum pressure is also derived for different intensity levels of the shock wave generator. The measurement is performed in the free field (i.e. in the absence of laser-generated single bubbles). In chapter 5 the interaction between lithotripter shock waves and laserinduced single cavitation bubbles is investigated experimentally. An

  15. The microphysics of collisionless shock waves

    Science.gov (United States)

    Marcowith, A.; Bret, A.; Bykov, A.; Dieckman, M. E.; O'C Drury, L.; Lembège, B.; Lemoine, M.; Morlino, G.; Murphy, G.; Pelletier, G.; Plotnikov, I.; Reville, B.; Riquelme, M.; Sironi, L.; Stockem Novo, A.

    2016-04-01

    Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space. It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in situ observations, analytical and numerical developments. A particular emphasis is made on the different instabilities triggered during the shock formation and in association with particle acceleration processes with regards to the properties of the background upstream medium. It appears that among the most important parameters the background magnetic field through the magnetization and its obliquity is the dominant one. The shock velocity that can reach relativistic speeds has also a strong impact over the development of the micro-instabilities and the fate of particle acceleration. Recent developments of laboratory shock experiments has started to bring some new insights in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics.

  16. The microphysics of collisionless shock waves.

    Science.gov (United States)

    Marcowith, A; Bret, A; Bykov, A; Dieckman, M E; Drury, L O'C; Lembège, B; Lemoine, M; Morlino, G; Murphy, G; Pelletier, G; Plotnikov, I; Reville, B; Riquelme, M; Sironi, L; Novo, A Stockem

    2016-04-01

    Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space. It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in situ observations, analytical and numerical developments. A particular emphasis is made on the different instabilities triggered during the shock formation and in association with particle acceleration processes with regards to the properties of the background upstream medium. It appears that among the most important parameters the background magnetic field through the magnetization and its obliquity is the dominant one. The shock velocity that can reach relativistic speeds has also a strong impact over the development of the micro-instabilities and the fate of particle acceleration. Recent developments of laboratory shock experiments has started to bring some new insights in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics.

  17. Shock wave compression behavior of aluminum foam

    Institute of Scientific and Technical Information of China (English)

    程和法; 黄笑梅; 薛国宪; 韩福生

    2003-01-01

    The shock wave compression behavior of the open cell aluminum foam with relative density of 0. 396 was studied through planar impact experiments. Using polyvinylidene fluoride(PVDF) piezoelectric gauge technique, the stress histories and propagation velocities of shock wave in the aluminum foam were measured and analyzed. The results show that the amplitude of shock wave attenuates rapidly with increasing the propagation distance in the aluminum foam, and an exponential equation of the normalized peak stress vs propagation distance of shock wave is established, the attenuation factor in the equation is 0. 286. Furthermore, the Hugoniot relation, νs = 516.85+ 1.27νp,for the aluminum foam is determined by empirical fit to the experimental Hugoniot data.

  18. Dispersive shock waves with nonlocal nonlinearity

    CERN Document Server

    Barsi, Christopher; Sun, Can; Fleischer, Jason W

    2007-01-01

    We consider dispersive optical shock waves in nonlocal nonlinear media. Experiments are performed using spatial beams in a thermal liquid cell, and results agree with a hydrodynamic theory of propagation.

  19. Dispersive shock waves with nonlocal nonlinearity.

    Science.gov (United States)

    Barsi, Christopher; Wan, Wenjie; Sun, Can; Fleischer, Jason W

    2007-10-15

    We consider dispersive optical shock waves in nonlocal nonlinear media. Experiments are performed using spatial beams in a thermal liquid cell, and results agree with a hydrodynamic theory of propagation.

  20. Density shock waves in confined microswimmers

    CERN Document Server

    Tsang, Alan Cheng Hou

    2015-01-01

    Motile and driven particles confined in microfluidic channels exhibit interesting emergent behavior from propagating density bands to density shock waves. A deeper understanding of the physical mechanisms responsible for these emergent structures is relevant to a number of physical and biomedical applications. Here, we study the formation of density shock waves in the context of an idealized model of microswimmers confined in a narrow channel and subject to a uniform external flow. Interestingly, these density shock waves exhibit a transition from `subsonic' with compression at the back to `supersonic' with compression at the front of the population as the intensity of the external flow increases. This behavior is the result of a non-trivial interplay between hydrodynamic interactions and geometric confinement, and is confirmed by a novel quasilinear wave model that properly captures the dependence of the shock formation on the external flow. These findings can be used to guide the development of novel mechan...

  1. Shock Wave Science and Technology Reference Library

    CERN Document Server

    2007-01-01

    Shock waves in multiphase flows refers to a rich variety of phenomena of interest to physicists, chemists, and fluid dynamicists, as well as mechanical, biomedical and aeronautical engineers. This volume treats shock and expansion waves in (bullet) complex, bubbly liquids (L van Wijngaarden, Y Tomita, V Kedrinskii) and (bullet) cryogenic liquids (M Murakami) and examines the relationship of shock waves with (bullet) phase transitions (A Guha, CF Delale, G Schnerr, MEH van Dongen) (bullet) induced phase transitions (GEA Meier) as well as their interaction with (bullet) solid foams, textiles, porous and granular media (B Skews, DMJ Smeulders, MEH van Dongen, V Golub, O Mirova) All chapters are self-contained, so they can be read independently, although they are of course thematically interrelated. Taken together, they offer a timely reference on shock waves in multiphase flows, including new viewpoints and burgeoning developments. The book will appeal to beginners as well as professional scientists and engineer...

  2. Medical and biomedical applications of shock waves

    CERN Document Server

    Loske, Achim M

    2017-01-01

    This book provides current, comprehensive, and clear explanations of the physics behind medical and biomedical applications of shock waves. Extracorporeal shock wave lithotripsy is one of the greatest medical advances of our time, and its techniques and clinical devices are continuously evolving. Further research continues to improve the understanding of calculi fragmentation and tissue-damaging mechanisms. Shock waves are also used in orthopedics and traumatology. Possible applications in oncology, cardiology, dentistry, gene therapy, cell transfection, transformation of fungi and bacteria, as well as the inactivation of microorganisms are promising approaches for clinical treatment, industrial applications and research. Medical and Biomedical Applications of Shock Waves is useful as a guide for students, technicians and researchers working in universities and laboratories. Chemists, biologists, physicians and veterinarians, involved in research or clinical practice will find useful advice, but also engineer...

  3. Existence Regions of Shock Wave Triple Configurations

    Science.gov (United States)

    Bulat, Pavel V.; Chernyshev, Mikhail V.

    2016-01-01

    The aim of the research is to create the classification for shock wave triple configurations and their existence regions of various types: type 1, type 2, type 3. Analytical solutions for limit Mach numbers and passing shock intensity that define existence region of every type of triple configuration have been acquired. The ratios that conjugate…

  4. Study of interaction between shock wave and unsteady boundary layer

    Institute of Scientific and Technical Information of China (English)

    董志勇; 韩肇元

    2003-01-01

    This paper reports theoretical and experimental study of a new type of interaction of a moving shock wave with an unsteady boundary layer. This type of shock wave-boundary layer interaction describes a moving shock wave interaction with an unsteady boundary layer induced by another shock wave and a rarefaction wave. So it is different from the interaction of a stationary shock wave with steady boundary layer, also different from the interaction of a reflected moving shock wave at the end of a shock tube with unsteady boundary layer induced by an incident shock. Geometrical shock dynamics is used for the theoretical analysis of the shock wave-unsteady boundary layer interaction, and a double-driver shock tube with a rarefaction wave bursting diaphragm is used for the experimental investigation in this work.

  5. Extracorporeal shock wave lithotripsy in childhood

    Energy Technology Data Exchange (ETDEWEB)

    Kroovand, R.L.; Harrison, L.H.; McCullough, D.L.

    1987-10-01

    Extracorporeal shock wave lithotripsy is the treatment of choice for the majority of upper urinary calculi in adults. Technical limitations, including patient size and concerns over post-treatment stone fragment passage, have made the application of extracorporeal shock wave lithotripsy in children less clearly defined. We report the successful application of the Dornier lithotriptor in the management of 18 children (22 kidneys) with upper urinary calculi.

  6. Shock Wave-Boundary Layer Interaction in Forced Shock Oscillations

    Institute of Scientific and Technical Information of China (English)

    Piotr Doerffer; Oskar Szulc; Franco Magagnato

    2003-01-01

    The flow in transonic diffusers as well as in supersonic air intakes becomes often unsteady due to shock wave boundary layer interaction. The oscillations may be induced by natural separation unsteadiness or may be forced by boundary conditions. Significant improvement of CFD tools, increase of computer resources as well as development of experimental methods have again.drawn the attention of researchers to this topic.To investigate the problem forced oscillations of transonic turbulent flow in asymmetric two-dimensional Laval nozzle were considered. A viscous, perfect gas flow, was numerically simulated using the Reynolds-averaged compressible Navier-Stokes solver SPARC, employing a two-equation, eddy viscosity, turbulence closure in the URANS approach.For time-dependent and stationary flow simulations, Mach numbers upstream of the shock between 1.2 and 1.4 were considered. Comparison of computed and experimental data for steady states generally gave acceptable agreement. In the case of forced oscillations, a harmonic pressure variation was prescribed at the exit plane resulting in shock wave motion. Excitation frequencies between 0 Hz and 1024 Hz were investigated at the same pressure amplitude.The main result of the work carried out is the relation between the amplitude of the shock wave motion and the excitation frequency in the investigated range. Increasing excitation frequency resulted in decreasing amplitude of the shock movement. At high frequencies a natural mode of shock oscillation (of small amplitude) was observed which is not sensitive to forced excitement.

  7. Rapid enhancement of low-energy (shocks based on two Van Allen Probes case studies: Implications for source regions and heating mechanisms

    Science.gov (United States)

    Yue, Chao; Li, Wen; Nishimura, Yukitoshi; Zong, Qiugang; Ma, Qianli; Bortnik, Jacob; Thorne, Richard M.; Reeves, Geoffrey D.; Spence, Harlan E.; Kletzing, Craig A.; Wygant, John R.; Nicolls, Michael J.

    2016-07-01

    Interactions between interplanetary (IP) shocks and the Earth's magnetosphere manifest many important space physics phenomena including low-energy ion flux enhancements and particle acceleration. In order to investigate the mechanisms driving shock-induced enhancement of low-energy ion flux, we have examined two IP shock events that occurred when the Van Allen Probes were located near the equator while ionospheric and ground observations were available around the spacecraft footprints. We have found that, associated with the shock arrival, electromagnetic fields intensified, and low-energy ion fluxes, including H+, He+, and O+, were enhanced dramatically in both the parallel and perpendicular directions. During the 2 October 2013 shock event, both parallel and perpendicular flux enhancements lasted more than 20 min with larger fluxes observed in the perpendicular direction. In contrast, for the 15 March 2013 shock event, the low-energy perpendicular ion fluxes increased only in the first 5 min during an impulse of electric field, while the parallel flux enhancement lasted more than 30 min. In addition, ionospheric outflows were observed after shock arrivals. From a simple particle motion calculation, we found that the rapid response of low-energy ions is due to drifts of plasmaspheric population by the enhanced electric field. However, the fast acceleration in the perpendicular direction cannot solely be explained by E × B drift but betatron acceleration also plays a role. Adiabatic acceleration may also explain the fast response of the enhanced parallel ion fluxes, while ion outflows may contribute to the enhanced parallel fluxes that last longer than the perpendicular fluxes.

  8. Critical point anomalies include expansion shock waves

    Energy Technology Data Exchange (ETDEWEB)

    Nannan, N. R., E-mail: ryan.nannan@uvs.edu [Mechanical Engineering Discipline, Anton de Kom University of Suriname, Leysweg 86, PO Box 9212, Paramaribo, Suriname and Process and Energy Department, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands); Guardone, A., E-mail: alberto.guardone@polimi.it [Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156 Milano (Italy); Colonna, P., E-mail: p.colonna@tudelft.nl [Propulsion and Power, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)

    2014-02-15

    From first-principle fluid dynamics, complemented by a rigorous state equation accounting for critical anomalies, we discovered that expansion shock waves may occur in the vicinity of the liquid-vapor critical point in the two-phase region. Due to universality of near-critical thermodynamics, the result is valid for any common pure fluid in which molecular interactions are only short-range, namely, for so-called 3-dimensional Ising-like systems, and under the assumption of thermodynamic equilibrium. In addition to rarefaction shock waves, diverse non-classical effects are admissible, including composite compressive shock-fan-shock waves, due to the change of sign of the fundamental derivative of gasdynamics.

  9. Shock wave science and technology reference library

    CERN Document Server

    2009-01-01

    This book, as a volume of the Shock Wave Science and Technology Reference Library, is primarily concerned with detonation waves or compression shock waves in reactive heterogeneous media, including mixtures of solid, liquid and gas phases. The topics involve a variety of energy release and control processes in such media - a contemporary research field that has found wide applications in propulsion and power, hazard prevention as well as military engineering. The six extensive chapters contained in this volume are: - Spray Detonation (SB Murray and PA Thibault) - Detonation of Gas-Particle Flow (F Zhang) - Slurry Detonation (DL Frost and F Zhang) - Detonation of Metalized Composite Explosives (MF Gogulya and MA Brazhnikov) - Shock-Induced Solid-Solid Reactions and Detonations (YA Gordopolov, SS Batsanov, and VS Trofimov) - Shock Ignition of Particles (SM Frolov and AV Fedorov) Each chapter is self-contained and can be read independently of the others, though, they are thematically interrelated. They offer a t...

  10. Experimental Investigation of Shock Wave Surfing

    CERN Document Server

    Parziale, N J; Hornung, H G; Shepherd, J E

    2010-01-01

    Shock wave surfing is investigated experimentally in GALCIT's Mach 4.0 Ludwieg Tube. Shock wave surfing occurs when a secondary free-body follows the bow shock formed by a primary free-body; an example of shock wave surfing occurs during meteorite breakup. The free-bodies in the current investigation are nylon spheres. During each run in the Ludwieg tube a high speed camera is used to capture a series of schlieren images; edge tracking software is used to measure the position of each sphere. Velocity and acceleration are had from processing the position data. The radius ratio and initial orientation of the two spheres are varied in the test matrix. The variation of sphere radius ratio and initial angle between the centers of gravity are shown to have a significant effect on the dynamics of the system.

  11. Transmission of light waves through normal shocks.

    Science.gov (United States)

    Hariharan, S I; Johnson, D K

    1995-11-20

    We seek to characterize light waves transmitted through normal shock waves. The investigation is motivated by the need for a theory to support a shadowgraph experiment for flow in a convergent-divergent nozzle. In this experiment light beams are passed through the nozzle transverse to the direction of the flow in which a shock has formed in the vicinity of the throat. We present a formulation and an approximation that yield calculations of the intensity of transmitted waves. We also present experimental results to support the theory. The patterns predicted by the theory compare well with the patterns observed in experiments.

  12. Plasma shock waves excited by THz radiation

    Science.gov (United States)

    Rudin, S.; Rupper, G.; Shur, M.

    2016-10-01

    The shock plasma waves in Si MOS, InGaAs and GaN HEMTs are launched at a relatively small THz power that is nearly independent of the THz input frequency for short channel (22 nm) devices and increases with frequency for longer (100 nm to 1 mm devices). Increasing the gate-to-channel separation leads to a gradual transition of the nonlinear waves from the shock waves to solitons. The mathematics of this transition is described by the Korteweg-de Vries equation that has the single propagating soliton solution.

  13. Extracorporeal shock wave therapy for tendinopathies.

    Science.gov (United States)

    Seil, Romain; Wilmes, Philippe; Nührenbörger, Christian

    2006-07-01

    Shock waves, as applied in urology and gastroenterology, were introduced in the middle of the last decade in Germany to treat different pathologies of the musculoskeletal system, including epicondylitis of the elbow, plantar fasciitis, and calcifying and noncalcifying tendinitis of the rotator cuff. With the noninvasive nature of these waves and their seemingly low complication rate, extracorporeal shock wave therapy (ESWT) seemed a promising alternative to the established conservative and surgical options in the treatment of patients with chronically painful conditions. However, the apparent advantages of the method led to a rapid diffusion and even inflationary use of ESWT; prospective, randomized studies on the mechanisms and effects of shock waves on musculoskeletal tissues were urgently needed to define more accurate indications and optimize therapeutic outcome. This review covers recent international research in the field and presents actual indications and results in therapy of musculoskeletal conditions with ESWT.

  14. The shock waves in decaying supersonic turbulence

    CERN Document Server

    Smith, M D; Zuev, J M; Smith, Michael D.; Low, Mordecai-Mark Mac; Zuev, Julia M.

    2000-01-01

    We here analyse numerical simulations of supersonic, hypersonic andmagnetohydrodynamic turbulence that is free to decay. Our goals are tounderstand the dynamics of the decay and the characteristic properties of theshock waves produced. This will be useful for interpretation of observations ofboth motions in molecular clouds and sources of non-thermal radiation. We find that decaying hypersonic turbulence possesses an exponential tail offast shocks and an exponential decay in time, i.e. the number of shocks isproportional to t exp (-ktv) for shock velocity jump v and mean initialwavenumber k. In contrast to the velocity gradients, the velocity ProbabilityDistribution Function remains Gaussian with a more complex decay law. The energy is dissipated not by fast shocks but by a large number of low Machnumber shocks. The power loss peaks near a low-speed turn-over in anexponential distribution. An analytical extension of the mapping closuretechnique is able to predict the basic decay features. Our analytic descrip...

  15. Shock Wave Structure in Particulate Composites

    Science.gov (United States)

    Rauls, Michael; Ravichandran, Guruswami

    2015-06-01

    Shock wave experiments are conducted on a particulate composite consisting of a polymethyl methacrylate (PMMA) matrix reinforced by glass beads. Such a composite with an impedance mismatch of 4.3 closely mimics heterogeneous solids of interest such as concrete and energetic materials. The composite samples are prepared using a compression molding process. The structure and particle velocity rise times of the shocks are examined using forward ballistic experiments. Reverse ballistic experiments are used to track how the interface density influences velocity overshoot above the steady state particle velocity. The effects of particle size (0.1 to 1 mm) and volume fraction of glass beads (30-40%) on the structure of the leading shock wave are investigated. It is observed that the rise time increases with increasing particle size and scales linearly for the range of particle sizes considered here. Results from numerical simulations using CTH are compared with experimental results to gain insights into wave propagation in heterogeneous particulate composites.

  16. Shock wave science and technology reference library

    CERN Document Server

    2009-01-01

    This book is the second of several volumes on solids in the Shock Wave Science and Technology Reference Library. These volumes are primarily concerned with high-pressure shock waves in solid media, including detonation and high-velocity impact and penetration events. Of the four extensive chapters in this volume, the first two describe the reactive behavior of condensed phase explosives, - Condensed-Phase Explosives: Shock Initiation and Detonation Phenomena (SA Sheffield and R Engelke) - First Principles Molecular Simulations of Energetic Materials at High-Pressures (F Zhang, S Alavi, and TK Woo), and the remaining two discuss the inert, mechanical response of solid materials. - Combined Compression and Shear Plane Waves (ZP Tang and JB Aidun), and - Dynamic Fragmentation of Solids (D Grady). All chapters are each self-contained, and can be read independently of each other. They offer a timely reference, for beginners as well as professional scientists and engineers, on the foundations of detonation phenomen...

  17. A pneumatic driver for shock wave production

    Science.gov (United States)

    Leftwich, Megan; Mejila-Alvarez, R.; Prestridge, K.

    2011-11-01

    We are presenting a novel technique to generate shock waves in shock tube experiments. Typically this is done with a high pressure driver section that is separated from the low pressure driven section by a physical membrane. The membrane is burst at a specific pressure and a shock wave is formed. This process limits the repetition of experiments, and membrane particles must be removed from the shock tube after each experiment. The driver presented here does not contain a membrane. Instead, it uses a series of high pressure chambers and fast-acting pistons to create the pressure jump between the high pressure driver section and low pressure driven section. The entire system is controlled remotely and requires no insertion or cleanup of membranes between experiments. The system is designed to achieve shock waves exceeding Mach 3 with air as the working fluid (higher Mach numbers can be generated with other working fluids). It will allow high repetition rates, even in challenging experimental environments (such as a vertical shock tube configuration). We present results from the initial characterization of this driver system.

  18. Reflection and Refraction of Acoustic Waves by a Shock Wave

    Science.gov (United States)

    Brillouin, J.

    1957-01-01

    The presence of sound waves in one or the other of the fluid regions on either side of a shock wave is made apparent, in the region under superpressure, by acoustic waves (reflected or refracted according to whether the incident waves lie in the region of superpressure or of subpressure) and by thermal waves. The characteristics of these waves are calculated for a plane, progressive, and uniform incident wave. In the case of refraction, the refracted acoustic wave can, according to the incidence, be plane, progressive, and uniform or take the form of an 'accompanying wave' which remains attached to the front of the shock while sliding parallel to it. In all cases, geometrical constructions permit determination of the kinematic characteristics of the reflected or refractive acoustic waves. The dynamic relationships show that the amplitude of the reflected wave is always less than that of the incident wave. The amplitude of the refracted wave, whatever its type, may in certain cases be greater than that of the incident wave.

  19. Propagation of shock waves through clouds

    Science.gov (United States)

    Zhou, Xin Xin

    1990-10-01

    The behavior of a shock wave propagating into a cloud consisting of an inert gas, water vapor and water droplets was investigated. This has particular application to sonic bangs propagating in the atmosphere. The finite different method of MacCormack is extended to solve the one and two dimensional, two phase flow problems in which mass, momentum and energy transfers are included. The FCT (Fluid Corrected Transport) technique developed by Boris and Book was used in the basic numerical scheme as a powerful corrective procedure. The results for the transmitted shock waves propagating in a one dimensional, semi infinite cloud obtained by the finite difference approach are in good agreement with previous results by Kao using the method characteristics. The advantage of the finite difference method is its adaptability to two and three dimensional problems. Shock wave propagation through a finite cloud and into an expansion with a 90 degree corner was investigated. It was found that the transfer processes between the two phases in two dimensional flow are much more complicated than in the one dimensional flow cases. This is mainly due to the vortex and expansion wave generated at the corner. In the case considered, further complications were generated by the reflected shock wave from the floor. Good agreement with experiment was found for one phase flow but experimental data for the two phase case is not yet available to validate the two phase calculations.

  20. Coastline sand waves on a low-energy beach at El Puntal spit, Spain: Linear stability analysis

    Science.gov (United States)

    MedellíN, G.; FalquéS, A.; Medina, R.; GonzáLez, M.

    2009-03-01

    Shoreline sand waves of approximately 125-150 m of wavelength and ≈15 m of amplitude in the offshore direction (reached in a few days) are often observed at the west end of El Puntal spit, Santander, Spain. They tend to last for about 2 months and do not show an evident alongshore propagation during that time. Since wave incidence on that beach is typically very oblique, a shoreline linear stability analysis is performed to test whether those sand waves could be generated by shoreline instability. Because of the low-energy wave climate and the steep mean bathymetric profile, the predicted wavelength (100-150 m) and growth time (4-8 days) are much smaller than is typical on open ocean beaches. This provides a unique opportunity to test high-angle wave instability. Thus, the role of the instability on the growth, evolution, and subsequent destruction of the sand waves is examined. A remarkable agreement between predictions and observations regarding the wavelength and growth time is found. Furthermore, by analyzing shoreline instability for a 2 year period where sand waves sometimes occur and sometimes do not, a clear correlation is found between sand wave occurrence and predicted instability growth rate. Intriguingly, results are less satisfactory regarding alongshore migration since the model predicts some migration that is not supported by observations. However, it becomes clear that the instability caused by high-angle waves is crucial for shoreline sand wave formation at El Puntal and should be considered for any future research.

  1. State of the art extracorporeal shock wave lithotripsy

    Energy Technology Data Exchange (ETDEWEB)

    Kandel, L.B. (State Univ. of New York at Stony Brook, Stony Brook, NY (US)); Harrison, L.H.; McCullough, D.L. (Wake Forest Univ. Medical Center, Winston-Salem, NC (US))

    1987-01-01

    This book contains 16 chapters. Some of the topics that are covered are: Extracorporeal Shock Wave Lithotripsy Development; Laser-Generated Extracorporeal Shock Wave Lithotripter; Radiation Exposure during ESWL; Caliceal Calculi; and Pediatric ESWL.

  2. Shock wave compression of condensed matter a primer

    CERN Document Server

    Forbes, Jerry W

    2012-01-01

    This book introduces the core concepts of the shock wave physics of condensed matter, taking a continuum mechanics approach to examine liquids and isotropic solids. The text primarily focuses on one-dimensional uniaxial compression in order to show the key features of condensed matter’s response to shock wave loading. The first four chapters are specifically designed to quickly familiarize physical scientists and engineers with how shock waves interact with other shock waves or material boundaries, as well as to allow readers to better understand shock wave literature, use basic data analysis techniques, and design simple 1-D shock wave experiments. This is achieved by first presenting the steady one-dimensional strain conservation laws using shock wave impedance matching, which insures conservation of mass, momentum and energy. Here, the initial emphasis is on the meaning of shock wave and mass velocities in a laboratory coordinate system. An overview of basic experimental techniques for measuring pressure...

  3. SPHERICAL SHOCK WAVES IN SOLIDS

    Science.gov (United States)

    Differential Equation of Self-Similar Motion; Application of the Theory of Self-Similar Motion to the Problem of Expansion of a Spherical...Self-Similar Solutions of the Problem of Cratering Due to Hypervelocity Impact, and Numerical Integration of the Differential Equation of Spherical...Aluminum, Blast Waves in Other Metals; and Consideration of the Non-Similar Aspects of the Blast Wave Problem ; Experimental Procedure and Results; Singular Point of Ordinary Differential Equations; Numerical Program-Fortran

  4. The experimental study of interaction between shock wave and turbulence

    Institute of Scientific and Technical Information of China (English)

    ZHAO YuXin; YI ShiHe; HE Lin; CHENG ZhongYu; TIAN LiFeng

    2007-01-01

    The interaction between shock wave and turbulence has been studied in supersonic turbulent mix layer wind tunnel. The interaction between oblique shock wave and turbulent boundary layer and the influence of large vortex in mix layer on oblique shock wave have been observed by NPLS technique. From NPLS image, not only complex flow structure is observed but also time-dependent supersonic flow visualization is realized. The mechanism of interaction between shock wave and turbulence is discussed based on high quality NPLS image.

  5. Generation of spherical and cylindrical shock acoustic waves from optical breakdown in water, stimulated with femtosecond pulse

    CERN Document Server

    Potemkin, F V; Podshivalov, A A; Gordienko, V M

    2014-01-01

    Using shadow photography technique we have observed shock acoustic wave from optical breakdown, excited in water by tightly focused Cr:Forsterite femtosecond laser beam, and have found two different regimes of shock wave generation by varying only the energy of laser pulse. At low energies a single spherical shock wave is generated from laser beam waist, and its radius tends to saturation with energy increasing. At higher energies long laser filament in water is fired, that leads to the cylindrical shock wave generation, which longitude increases logarithmically with laser pulse energy. From shadow pictures we estimated maximal velocity in front or shock wave of 2300+/-150m/s and pressure of 1.0+/-0.1 GPa

  6. High Temperature Phenomena in Shock Waves

    CERN Document Server

    2012-01-01

    The high temperatures generated in gases by shock waves give rise to physical and chemical phenomena such as molecular vibrational excitation, dissociation, ionization, chemical reactions and inherently related radiation. In continuum regime, these processes start from the wave front, so that generally the gaseous media behind shock waves may be in a thermodynamic and chemical non-equilibrium state. This book presents the state of knowledge of these phenomena. Thus, the thermodynamic properties of high temperature gases, including the plasma state are described, as well as the kinetics of the various chemical phenomena cited above. Numerous results of measurement and computation of vibrational relaxation times, dissociation and reaction rate constants are given, and various ionization and radiative mechanisms and processes are presented. The coupling between these different phenomena is taken into account as well as their interaction with the flow-field. Particular points such as the case of rarefied flows an...

  7. Structure of the plasmapause from ISEE 1 low-energy ion and plasma wave observations

    Science.gov (United States)

    Nagai, T.; Horwitz, J. L.; Anderson, R. R.; Chappell, C. R.

    1985-01-01

    Low-energy ion pitch angle distributions are compared with plasma density profiles in the near-earth magnetosphere using ISEE 1 observations. The classical plasmapause determined by the sharp density gradient is not always observed in the dayside region, whereas there almost always exists the ion pitch angle distribution transition from cold, isotropic to warm, bidirectional, field-aligned distributions. In the nightside region the plasmapause density gradient is typically found, and it normally coincides with the ion pitch angle distribution transition. The sunward motion of the plasma is found in the outer part of the 'plasmaspheric' plasma in the dusk bulge region.

  8. Extracorporeal shock wave therapy does not improve hypertensive nephropathy.

    Science.gov (United States)

    Caron, Jonathan; Michel, Pierre-Antoine; Dussaule, Jean-Claude; Chatziantoniou, Christos; Ronco, Pierre; Boffa, Jean-Jacques

    2016-06-01

    Low-energy extracorporeal shock wave therapy (SWT) has been shown to improve myocardial dysfunction, hind limb ischemia, erectile function, and to facilitate cell therapy and healing process. These therapeutic effects were mainly due to promoting angiogenesis. Since chronic kidney diseases are characterized by renal fibrosis and capillaries rarefaction, they may benefit from a proangiogenic treatment. The objective of our study was to determine whether SWT could ameliorate renal repair and favor angiogenesis in L-NAME-induced hypertensive nephropathy in rats. SWT was started when proteinuria exceeded 1 g/mmol of creatinine and 1 week after L-NAME removal. SWT consisted of implying 0.09 mJ/mm(2) (400 shots), 3 times per week. After 4 weeks of SWT, blood pressure, renal function and urinary protein excretion did not differ between treated (LN + SWT) and untreated rats (LN). Histological lesions including glomerulosclerosis and arteriolosclerosis scores, tubular dilatation and interstitial fibrosis were similar in both groups. In addition, peritubular capillaries and eNOS, VEGF, VEGF-R, SDF-1 gene expressions did not increase in SWT-treated compared to untreated animals. No procedural complications or adverse effects were observed in control (C + SWT) and hypertensive rats (LN + SWT). These results suggest that extracorporeal kidney shock wave therapy does not induce angiogenesis and does not improve renal function and structure, at least in the model of hypertensive nephropathy although the treatment is well tolerated.

  9. Extracorporeal shock waves as curative therapy for varicose veins?

    Directory of Open Access Journals (Sweden)

    Fiorenzo Angehrn

    2008-03-01

    Full Text Available Fiorenzo Angehrn1, Christoph Kuhn1, Ortrud Sonnabend2, Axel Voss31Klinik Piano, Biel, Switzerland; 2Pathodiagnostics, Herisau, Switzerland; 3SwiTech Medical AG, Kreuzlingen, SwitzerlandAbstract: In this prospective design study the effects of low-energy partially focused extracorporeal generated shock waves (ESW onto a subcutaneous located varicose vein – left vena saphena magna (VSM – are investigated. The treatment consisted of 4 ESW applications within 21 days. The varicose VSM of both sides were removed by surgery, and samples analyzed comparing the treated and untreated by means of histopathology. No damage to the treated varicose vein in particular and no mechanical destruction to the varicose vein’s wall could be demonstrated. However, an induction of neo-collagenogenesis was observed. The thickness of the varicose vein’s wall increased. Optimization of critical application parameters by investigating a larger number of patients may turn ESW into a non-invasive curative varicose treatment.Keywords: curative therapy, extra-cellular matrix (ECM, histopathologic changes of varicose veins, extracorporeal shock wave (ESW, progenitor cells

  10. Low-Energy Quasiparticle States near Extended Scatterers in d -Wave Superconductors and Their Connection with SUSY Quantum Mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Adagideli, Inanc; Goldbart, Paul M.; Shnirman, Alexander; Yazdani, Ali

    1999-12-27

    Low-energy quasiparticle states, arising from scattering by single-particle potentials in d -wave superconductors, are addressed. Via a natural extension of the Andreev approximation, the idea that sign variations in the superconducting pair potential lead to such states is extended beyond its original setting of boundary scattering to the broader context of scattering by general single-particle potentials, such as those due to impurities. The index-theoretic origin of these states is exhibited via a simple connection with Witten's supersymmetric quantum-mechanical model. (c) 1999 The American Physical Society.

  11. Analgesic effect of extracorporeal shock-wave therapy on chronic tennis elbow.

    Science.gov (United States)

    Rompe, J D; Hope, C; Küllmer, K; Heine, J; Bürger, R

    1996-03-01

    We report a controlled, prospective study to investigate the effect of treatment by low-energy extracorporeal shock waves on pain in tennis elbow. We assigned at random 100 patients who had had symptoms for more than 12 months to two groups to receive low-energy shock-wave therapy. Group I received a total of 3000 impulses of 0.08 mJ/mm2 and group II, the control group, 30 impulses. The patients were reviewed after 3, 6 and 24 weeks. There was significant alleviation of pain and improvement of function after treatment in group I in which there was a good or excellent outcome in 48% and an acceptable result in 42% at the final review, compared with 6% and 24%, respectively, in group II.

  12. Holographic flow visualization of time-varying shock waves

    Science.gov (United States)

    Decker, A. J.

    1981-01-01

    Rapid-double-exposure, diffuse-illumination holography is evaluated analytically and experimentally as a flow visualization method for time-varying shock waves. Conditions are determined that minimize the distance (localization error) between the surface or curve of interference-fringe localization and the shock surface. Treated specifically are the cases of shock waves in a transonic compressor rotor for which there is laser anemometer data for comparison and shock waves in a flutter cascade.

  13. Shock Waves in Dense Hard Disk Fluids

    CERN Document Server

    Sirmas, Nick; Barahona, Javier; Radulescu, Matei I

    2011-01-01

    Media composed of colliding hard disks (2D) or hard spheres (3D) serve as good approximations for the collective hydrodynamic description of gases, liquids and granular media. In the present study, the compressible hydrodynamics and shock dynamics are studied for a two-dimensional hard-disk medium at both the continuum and discrete particle level descriptions. For the continuum description, closed form analytical expressions for the inviscid hydrodynamic description, shock Hugoniot, isentropic exponent and shock jump conditions were obtained using the Helfand equation of state. The closed-form analytical solutions permitted us to gain physical insight on the role of the material's density on its compressibility, i.e. how the medium compresses under mechanical loadings and sustains wave motion. Furthermore, the predictions were found in excellent agreement with calculations using the Event Driven Molecular Dynamic method involving 30,000 particles over the entire range of compressibility spanning the dilute id...

  14. Fluid dynamics of the shock wave reactor

    Science.gov (United States)

    Masse, Robert Kenneth

    2000-10-01

    High commercial incentives have driven conventional olefin production technologies to near their material limits, leaving the possibility of further efficiency improvements only in the development of entirely new techniques. One strategy known as the Shock Wave Reactor, which employs gas dynamic processes to circumvent limitations of conventional reactors, has been demonstrated effective at the University of Washington. Preheated hydrocarbon feedstock and a high enthalpy carrier gas (steam) are supersonically mixed at a temperature below that required for thermal cracking. Temperature recovery is then effected via shock recompression to initiate pyrolysis. The evolution to proof-of-concept and analysis of experiments employing ethane and propane feedstocks are presented. The Shock Wave Reactor's high enthalpy steam and ethane flows severely limit diagnostic capability in the proof-of-concept experiment. Thus, a preliminary blow down supersonic air tunnel of similar geometry has been constructed to investigate recompression stability and (especially) rapid supersonic mixing necessary for successful operation of the Shock Wave Reactor. The mixing capabilities of blade nozzle arrays are therefore studied in the air experiment and compared with analytical models. Mixing is visualized through Schlieren imaging and direct photography of condensation in carbon dioxide injection, and interpretation of visual data is supported by pressure measurement and flow sampling. The influence of convective Mach number is addressed. Additionally, thermal behavior of a blade nozzle array is analyzed for comparison to data obtained in the course of succeeding proof-of-concept experiments. Proof-of-concept is naturally succeeded by interest in industrial adaptation of the Shock Wave Reactor, particularly with regard to issues involving the scaling and refinement of the shock recompression. Hence, an additional, variable geometry air tunnel has been constructed to study the parameter

  15. Shock-Induced Borehole Waves and Fracture Effects

    NARCIS (Netherlands)

    Fan, H.; Smeulders, D.M.

    2011-01-01

    We perform wave experiments using a vertical shock tube setup. Shock waves are generated by the rupture of a thin membrane. In the test section, the incident pressure waves generate borehole-guided waves along water-saturated samples. The tube is equipped with side wall gages and a mobile pressure p

  16. Shock-Induced Borehole Waves and Fracture Effects

    NARCIS (Netherlands)

    Fan, H.; Smeulders, D.M.

    2011-01-01

    We perform wave experiments using a vertical shock tube setup. Shock waves are generated by the rupture of a thin membrane. In the test section, the incident pressure waves generate borehole-guided waves along water-saturated samples. The tube is equipped with side wall gages and a mobile pressure p

  17. Low Energy Particle Oscillations and Correlations with Hydromagnetic Waves in the Jovian Magnetosphere: Ulysses Measurements

    Science.gov (United States)

    Krupp, N.; Tsurutani, B. T.; Lanzerotti, L. J.; Maclennan, C. G.

    1996-01-01

    We report on measurements of energetic particle modulations observed by the HI-SCALE instrument aboard the Ulysses Spacecraft that were associated with the only hydromagnetic wave event measured inside the Jovian magnetosphere by the Ulysses magnetometer investigation.

  18. Stability of spherical converging shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, M., E-mail: murakami-m@ile.osaka-u.ac.jp [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Sanz, J. [ETSI Aeronauticos, Universidad Politecnica de Madrid, Madrid 28040 (Spain); Iwamoto, Y. [Graduate School of Science and Engineering, Ehime University, Ehime 790-8577 (Japan)

    2015-07-15

    Based on Guderley's self-similar solution, stability of spherical converging shock wave is studied. A rigorous linear perturbation theory is developed, in which the growth rate of perturbation is given as a function of the spherical harmonic number ℓ and the specific heats ratio γ. Numerical calculation reveals the existence of a γ-dependent cut-off mode number ℓ{sub c}, such that all the eigenmode perturbations for ℓ > ℓ{sub c} are smeared out as the shock wave converges at the center. The analysis is applied to partially spherical geometries to give significant implication for different ignition schemes of inertial confinement fusion. Two-dimensional hydrodynamic simulations are performed to verify the theory.

  19. Velocity variation of internal shock waves in gamma ray bursts: Observational properties

    Institute of Scientific and Technical Information of China (English)

    WU; Mei; CHEN; Li; QU; Jinlu; Poon; Helen; WU; Bobing; SONG; Liming

    2006-01-01

    The work uses the data in the TTS mode of BATSE to analyze the time lags and pulse widths of GRB960113 and GRB960722 in high as well as low energy bands. The results show that their time lags increase monotonously. This phenomenon can reasonably be interpreted with the model of internal shock waves of γ-ray bursts (GRB). Perhaps we obtain the direct observational evidence for the fireball model of GRBs for the first time.

  20. Shock-Wave Boundary Layer Interactions

    Science.gov (United States)

    1986-02-01

    proprietes de la couche limite subissent au cours de I’interaction; les methodes integrales ou aux differences finies qui permettent le calcul continu de...interesse par la recherche d’une plus ample information. CONTENTS Page PREFACE »’ INTRODUCTION 1 PART I: A PHYSICAL DESCRIPTION OF SHOCK-WAVE/BOUNDARY...References 105 109 PART II: METHODS OF CALCULATION GLOBAL METHODS 1.1 Introductory Remarks 109 1.2 Two-Dimensional Interactions HO 1.2.1

  1. Shock Waves and the Origin of Life

    Science.gov (United States)

    1977-01-01

    describes it, the visitors having a picnic on the virgin planet, left their refuse behind and the microbial resident of the primordial cookie crumb may be...upon dissolution in the primordial oceans, become available for further chemical evolution. Based on the availability of thunder shock-waves on the...replicating system has evolved, it could propagate without interruption, having the whole organic " soup " in the oceans as its food source. Indeed, one of the

  2. Heating Cooling Flows with Weak Shock Waves

    CERN Document Server

    Mathews, W G; Brighenti, F

    2006-01-01

    The discovery of extended, approximately spherical weak shock waves in the hot intercluster gas in Perseus and Virgo has precipitated the notion that these waves may be the primary heating process that explains why so little gas cools to low temperatures. This type of heating has received additional support from recent gasdynamical models. We show here that outward propagating, dissipating waves deposit most of their energy near the center of the cluster atmosphere. Consequently, if the gas is heated by (intermittent) weak shocks for several Gyrs, the gas within 30-50 kpc is heated to temperatures that far exceed observed values. This heating can be avoided if dissipating shocks are sufficiently infrequent or weak so as not to be the primary source of global heating. Local PV and viscous heating associated with newly formed X-ray cavities are likely to be small, which is consistent with the low gas temperatures generally observed near the centers of groups and clusters where the cavities are located.

  3. THE INTERACTION BETWEEN SHOCK WAVES AND SOLID SPHERES ARRAYS IN A SHOCK TUBE

    Institute of Scientific and Technical Information of China (English)

    SHI Honghui; Kazuki YAMAMURA

    2004-01-01

    When a shock wave interacts with a group of solid spheres, non-linear aerodynamic behaviors come into effect. The complicated wave reflections such as the Mach reflection occur in the wave propagation process. The wave interactions with vortices behind each sphere's wake cause fluctuation in the pressure profiles of shock waves. This paper reports an experimental study for the aerodynamic processes involved in the interaction between shock waves and solid spheres. A schlieren photography was applied to visualize the various shock waves passing through solid spheres. Pressure measurements were performed along different downstream positions. The experiments were conducted in both rectangular and circular shock tubes. The data with respect to the effect of the sphere array,size, interval distance, incident Mach number, etc., on the shock wave attenuation were obtained.

  4. Morphodynamic modeling of low energy beaches under waves, tides and currents

    Science.gov (United States)

    Ruiz, G.; Marino-Tapia, I.

    2013-05-01

    Natural processes such as coastal erosion or sediment accretion on beaches are produced by the interaction of physical forces in the littoral zone; these coastal processes can attain equilibrium states in the mid- and long term at beaches. Elements that contribute to such behaviour are the cumulative effects of waves, tides and shelf currents, which generate flow, sediment and wave patterns that shape the beach. However, over recent decades, coastal erosion has been intensified by the accelerated growth of the human population, urbanization and land development on coastal boundaries, which modify natural processes. This study shows the results of hydro-morphological numerical modeling of the northern beaches of Yucatán, Mexico, in which erosion problems are identified. The 2D-numerical simulations were carried out using the WAVE, FLOW and MOR models of DELFT 3D. The forcing elements which were used in the simulations, such as wave, tide and wind data were determined from oceanographical equipment and meteorological instruments that were located at the Yucatan coast. A nested model was used in the simulations in order to incorporate a detailed grid with a spatial resolution of 3 m within an overall larger grid. The detailed grid had 27,000 cells and covered a littoral cell of 800 x 200 m. Subsequently, an analysis of kinetic energy was performed to evaluate the grid and WAVE+ FLOW model stability. On the other hand, the calibration and validation tests were carried out through the comparison of computed and measured volumetric changes; the measured data were obtained from two field surveys where the change in the volume sediments was calculated from the evolution of a beach profile, over a span of 55 days. As a result of the validation test, the error between data and model was of ±3%. In order to identify which forcing is the most relevant for the coastal processes of these beaches, various scenarios were tested. Furthermore, an arrangement of six control volume

  5. Observation of Strong Reflection of Electron Waves Exiting a Ballistic Channel at Low Energy

    Science.gov (United States)

    Vaz, Canute I.; Liu, Changze; Campbell, Jason P.; Ryan, Jason T.; Southwick, Richard G.; Gundlach, David; Oates, Anthony S.; Huang, Ru; Cheung, Kin. P.

    2016-01-01

    Wave scattering by a potential step is a ubiquitous concept. Thus, it is surprising that theoretical treatments of ballistic transport in nanoscale devices, from quantum point contacts to ballistic transistors, assume no reflection even when the potential step is encountered upon exiting the device. Experiments so far seem to support this even if it is not clear why. Here we report clear evidence of coherent reflection when electron wave exits the channel of a nanoscale transistor and when the electron energy is low. The observed behavior is well described by a simple rectangular potential barrier model which the Schrodinger's equation can be solved exactly. We can explain why reflection is not observed in most situations but cannot be ignored in some important situations. Our experiment also represents a direct measurement of electron injection velocity - a critical quantity in nanoscale transistors that is widely considered not measurable. PMID:27882264

  6. The Shock Wave in the ionosphere during an Earthquake

    Directory of Open Access Journals (Sweden)

    Kuznetsov Vladimir

    2016-01-01

    Full Text Available Fundamentally new model of the shock wave (SW generation in atmosphere and ionosphere during earthquake is proposed. The model proceeds from the idea of cooperative shock water crystallization in a cloud.

  7. Propagation of shock waves in a viscous medium

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Harish C; Anand, R K, E-mail: harish0chandra@gmail.com, E-mail: anand.rajkumar@rediffmail.com [Department of Physics, University of Allahabad, Allahabad-211002 (India)

    2011-06-01

    A theoretical model for entropy production in a viscous medium due to the propagation of shock waves has been developed. An exact general solution is achieved for plane, cylindrical and spherical symmetries of shock waves in viscous flow, which on numerical substitutions gives variations in the entropy production, temperature ratio and particle velocity in the shock transition region with the coefficient of viscosity, specific heat ratio, shock strength, initial density and initial pressure.

  8. Shock Waves Science and Technology Library

    CERN Document Server

    2012-01-01

    This book, as a volume of the Shock Wave Science and Technology Reference Library, is primarily concerned with the fundamental theory of detonation physics in gaseous and condensed phase reactive media. The detonation process involves complex chemical reaction and fluid dynamics, accompanied by intricate effects of heat, light, electricity and magnetism - a contemporary research field that has found wide applications in propulsion and power, hazard prevention as well as military engineering. The seven extensive chapters contained in this volume are: - Chemical Equilibrium Detonation (S. Bastea and LE Fried) - Steady One-Dimensional Detonations (A Higgins) - Detonation Instability (HD Ng and F Zhang) - Dynamic Parameters of Detonation (AA Vasiliev) - Multi-Scaled Cellular Detonation (D Desbordes and HN Presles) - Condensed Matter Detonation: Theory and Practice (C Tarver) - Theory of Detonation Shock Dynamics (JB Bdzil and DS Stewart) The chapters are thematically interrelated in a systematic descriptive appro...

  9. Propagation of shock waves in a magneto viscous medium

    CERN Document Server

    Anand, R K; Mishra, Manoj K

    2012-01-01

    Recently the authors [Phys. Scr. 83 (2011) 065402] have studied the entropy production in a viscous medium due to the propagation of shock waves. In the present paper, a theoretical model has been developed for a more realistic problem that deals with the study of entropy production due to propagation of shock waves in a viscous medium under the effect of a static magnetic field, for the cases of plane, cylindrical and spherical symmetry of the shock. Exact solutions for the flow variables have been discovered and their numerical estimations in the shock transition region have been analyzed with respect to static magnetic field, shock symmetry, shock strength, and specific heat ratio.

  10. Shock Wave-Stimulated Periosteum for Cartilage Repair

    Science.gov (United States)

    2015-03-01

    AD_________________ Award Number: W81XWH-10-1-0914 TITLE: Shock Wave-Stimulated Periosteum for Cartilage Repair PRINCIPAL INVESTIGATOR...30Sep2010 – 1Dec2014 4. TITLE AND SUBTITLE Shock Wave-Stimulated Periosteum for Cartilage Repair 5a. CONTRACT NUMBER W81XWH-10-1-0914 5b. GRANT NUMBER... shock wave (ESW)-stimulated periosteum improves cartilage repair when it is used as an autograft to fill a defect in the articular surface of goats. A

  11. Extracorporeal Shock Wave Therapy for Nonunion of the Tibia

    Science.gov (United States)

    2010-03-01

    Zoellner J, Nafe B. Shock wave therapy versus conventional surgery in the treatment of calcifying tendinitis of the shoulder. Clin Orrhop Relar Res. 200...I ;387:72-82. 26. Wang CJ, Yang KD, Wang FS. ct al. Shock wave therapy for culcific tendinitis of the shoulder: a prospective clinical study with...Selvi E, ct al. Extracorporeal shock wave therapy for chronic calcific tendinitis of the shoulder: single blind study. Ann Rheum Dis. 2(K13;62:248

  12. Internal energy relaxation in shock wave structure

    Science.gov (United States)

    Josyula, Eswar; Suchyta, Casimir J.; Boyd, Iain D.; Vedula, Prakash

    2013-12-01

    The Wang Chang-Uhlenbeck (WCU) equation is numerically integrated to characterize the internal structure of Mach 3 and Mach 5 shock waves in a gas with excitation in the internal energy states for the treatment of inelastic collisions. Elastic collisions are modeled with the hard sphere collision model and the transition rates for the inelastic collisions modified appropriately using probabilities based on relative velocities of the colliding particles. The collision integral is evaluated by the conservative discrete ordinate method [F. Tcheremissine, "Solution of the Boltzmann kinetic equation for high-speed flows," Comput. Math. Math. Phys. 46, 315-329 (2006); F. Cheremisin, "Solution of the Wang Chang-Uhlenbeck equation," Dokl. Phys. 47, 487-490 (2002)] developed for the Boltzmann equation. For the treatment of the diatomic molecules, the internal energy modes in the Boltzmann equation are described quantum mechanically given by the WCU equation. As a first step in the treatment of the inelastic collisions by the WCU equation, a two- and three-quantum system is considered to study the effect of the varying of (1) the inelastic cross section and (2) the energy gap between the quantum energy states. An alternative method, the direct simulation Monte Carlo method, is used for the Mach 3 shock wave to ensure the consistency of implementation in the two methods and there is an excellent agreement between the two methods. The results from the WCU implementation showed consistent trends for the Mach 3 and Mach5 standing shock waves simulations. Inelastic contributions change the downstream equilibrium state and allow the flow to transition to the equilibrium state further upstream.

  13. pp {r_reversible} {pi}{sup +}d process at low energy: interplay between s- and p-wave mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Canton, L. [Istituto Nazionale di Fiscia Nucleare, Sezione di Padova (Italy)]|[Universita di Padova, (Italy). Dipartimento di Fisica; Davini, A. [Universita di Padova, (Italy). Dipartimento di Fisica; Dortmans, P.J. [University of Melbourne, Parkville, VIC (Australia). School of Physics

    1997-12-31

    The large variety of experimental data around the pion-production threshold are compared with a meson-exchange isobar model which includes the pion-nucleon interaction in s- and p-waves. Theoretical results obtained with two different NN potentials (Bonn and Paris) indicate that the behavior of the excitation function at threshold is sensitive to the details of the NN correlations. The complete model presented, while developed originally to reproduce the reaction around the {Delta} resonance, is shown to describe well the integral (Coulomb-corrected) cross-section at threshold along with its angular distribution. At low energies the angular dependence of the analyzing power A{sub yo} is well reproduced also. Finally, the energy dependence of the analyzing power for {theta} = 90 deg from threshold up to the {Delta} resonance is considered and discussed. (authors) 38 refs., 2 tabs., 6 figs.

  14. [The influence of low-energy millimeter electromagnetic waves on the stability of DNA molecules in solution].

    Science.gov (United States)

    Babaian; Markarian, A Sh; Kalantarian, V P; Kazarian, R S; Parsadanian, M A; Vardevanian, P O

    2007-01-01

    The influence of low-energy millimeter electromagnetic waves on aqueous saline solution of DNA from the liver of healthy rats and rats with sarcoma 45 has been investigated. The characteristic parameters of irradiated and unirradiated DNA, melting temperature, and the range of melting were obtained from melting curves. The duration of exposure did not practically affect the range of melting, while the thermostability of DNA increased; as irradiation duration increased to 90 min, the melting temperature of tumor increased by approximately 1.5 degrees C. It was assumped that the increase in the thermostability of DNA is due to a more effective stabilization of the DNA double helix caused by the dehydration of Na(+)- ions present in the solution.

  15. Strong Antigravity. Life in the Shock Wave

    CERN Document Server

    Fabbrichesi, Marco E

    1992-01-01

    Strong anti-gravity is the vanishing to all orders in Newton's constant of the net force between two massive particles at rest. We study this phenomenon and show that it occurs in any effective theory of gravity which is obtained from a higher-dimensional model by compactification on a manifold with flat directions. We find the exact solution of the Einstein equations in the presence of a point-like source of strong anti-gravity by dimensional reduction of what is a shock-wave solution in the higher-dimensional model. (Latex file, no macros, figures not included)

  16. Extracorporeal shock-wave lithotripsy of gallstones. Results and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Staritz, M.; Rambow, A.; Meyer zum Bueschenfelde, K.H.; Floth, A.; Hohenfellner, R.; Mildenberger, P.; Thelen, M.; Goebel, M.

    1987-12-01

    Recently extracorporeal shock-wave lithotripsy became a noteworthy alternative in the treatment of choledocolithiasis and cholecystolithiasis, in particular since the introduction of the second-generation shock-wave technique which allows to dispense with the positioning of the patient in the water bath required sofar and to place the patient on an examination table in freely movable way so as to position the gall stone to be disintegrated in the focus of the shock waves. Despite the beneficial treatment results, extracorporeal shock-wave lithotripsy still needs further improvement as a method especially in terms of the option of 'pulverizing' the stones. (orig./TRV)

  17. Development on Adjustable Calibration Marker for Shock Wave Focus

    Institute of Scientific and Technical Information of China (English)

    Xi-zhao Sun; Zhi-wei Zhang

    2005-01-01

    @@ Shock wave lithotripsy (SWL) is a treatment of choice for upper urinary stones. However, this procedure is inappropriate for obese patients because the focus is often unable to reach the target owing to the limited focal distance in shock wave source. Although treating such patients in a blast path may increase the application length of shock wave source,it's difficult to find this path on the lithotripter monitor. For this reason, we invented an adjustable calibration marker in order to set an effective focus in the shock wave path.

  18. Shock waves in dispersive Eulerian fluids

    CERN Document Server

    Hoefer, M A

    2013-01-01

    The long time behavior of an initial step resulting in a dispersive shock wave (DSW) for the one-dimensional isentropic Euler equations regularized by generic, third order dispersion is considered by use of Whitham averaging. Under modest assumptions, the jump conditions (DSW locus and speeds) for admissible, weak DSWs are characterized and found to depend only upon the sign of dispersion (convex or concave) and a general pressure law. Two mechanisms leading to the breakdown of this simple wave DSW theory for sufficiently large jumps are identified: a change in the sign of dispersion, leading to gradient catastrophe in the modulation equations, and the loss of genuine nonlinearity in the modulation equations. Large amplitude DSWs are constructed for several particular dispersive fluids with differing pressure laws modeled by the generalized nonlinear Schr\\"{o}dinger equation. These include superfluids (Bose-Einstein condensates and ultracold Fermions) and "optical fluids". Estimates of breaking times for smoo...

  19. Observation and control of shock waves in individual nanoplasmas

    CERN Document Server

    Hickstein, Daniel D; Gaffney, Jim A; Foord, Mark E; Petrov, George M; Palm, Brett B; Keister, K Ellen; Ellis, Jennifer L; Ding, Chengyuan; Libby, Stephen B; Jimenez, Jose L; Kapteyn, Henry C; Murnane, Margaret M; Xiong, Wei

    2014-01-01

    In a novel experiment that images the momentum distribution of individual, isolated 100-nm-scale plasmas, we make the first experimental observation of shock waves in nanoplasmas. We demonstrate that the introduction of a heating pulse prior to the main laser pulse increases the intensity of the shock wave, producing a strong burst of quasi-monochromatic ions with an energy spread of less than 15%. Numerical hydrodynamic calculations confirm the appearance of accelerating shock waves, and provide a mechanism for the generation and control of these shock waves. This observation of distinct shock waves in dense plasmas enables the control, study, and exploitation of nanoscale shock phenomena with tabletop-scale lasers.

  20. An overview of shock wave therapy in musculoskeletal disorders.

    Science.gov (United States)

    Wang, Ching-Jen

    2003-04-01

    Shock waves are high-energy acoustic waves generated under water with high voltage explosion and vaporization. Shock wave in urology (lithotripsy) is primarily used to disintegrate urolithiasis, whereas shock wave in orthopedics (orthotripsy) is not used to disintegrate tissues, rather to induce neovascularization, improve blood supply and tissue regeneration. The application of shock wave therapy in certain musculoskeletal disorders has been around for approximately 15 years, and the success rate in non-union of long bone fracture, calcifying tendonitis of the shoulder, lateral epicondylitis of the elbow and proximal plantar fasciitis ranged from 65% to 91%. The complications are low and negligible. Recently, shock wave therapy was extended to treat other conditions including avascular necrosis of femoral head, patellar tendonitis (jumper's knee), osteochondritis dessicans and non-calcifying tendonitis of the shoulder. Shock wave therapy is a novel therapeutic modality without the need of surgery and surgical risks as well as surgical pain. It is convenient and cost-effective. The exact mechanism of shock wave therapy remains unknown. Based on the results of animal studies in our laboratory, it appears that the mechanism of shock waves first stimulates the early expression of angiogenesis-related growth factors including eNOS (endothelial nitric oxide synthase), VEGF (vessel endothelial growth factor) and PCNA (proliferating cell nuclear antigen), then induces the ingrowth of neovascularization that improves blood supply and increases cell proliferation and eventual tissue regeneration to repair tendon or bone tissues. The rise of angiogenic markers occurred in as early as one week and only lasted for approximately 8 weeks, whereas the neovascularization was first noted in 4 weeks and persisted for 12 weeks or longer along with cell proliferation. These findings support the clinical observation that the effect of shock wave therapy appears to be dose-dependent and

  1. Radial Shock Wave Devices Generate Cavitation.

    Directory of Open Access Journals (Sweden)

    Nikolaus B M Császár

    Full Text Available Conflicting reports in the literature have raised the question whether radial extracorporeal shock wave therapy (rESWT devices and vibrating massage devices have similar energy signatures and, hence, cause similar bioeffects in treated tissues.We used laser fiber optic probe hydrophone (FOPH measurements, high-speed imaging and x-ray film analysis to compare fundamental elements of the energy signatures of two rESWT devices (Swiss DolorClast; Electro Medical Systems, Nyon, Switzerland; D-Actor 200; Storz Medical, Tägerwillen, Switzerland and a vibrating massage device (Vibracare; G5/General Physiotherapy, Inc., Earth City, MO, USA. To assert potential bioeffects of these treatment modalities we investigated the influence of rESWT and vibrating massage devices on locomotion ability of Caenorhabditis elegans (C. elegans worms.FOPH measurements demonstrated that both rESWT devices generated acoustic waves with comparable pressure and energy flux density. Furthermore, both rESWT devices generated cavitation as evidenced by high-speed imaging and caused mechanical damage on the surface of x-ray film. The vibrating massage device did not show any of these characteristics. Moreover, locomotion ability of C. elegans was statistically significantly impaired after exposure to radial extracorporeal shock waves but was unaffected after exposure of worms to the vibrating massage device.The results of the present study indicate that both energy signature and bioeffects of rESWT devices are fundamentally different from those of vibrating massage devices.Prior ESWT studies have shown that tissues treated with sufficient quantities of acoustic sound waves undergo cavitation build-up, mechanotransduction, and ultimately, a biological alteration that "kick-starts" the healing response. Due to their different treatment indications and contra-indications rESWT devices cannot be equated to vibrating massage devices and should be used with due caution in clinical

  2. Neutrino signal of supernova shock wave propagation:MSW distortion of the spectra and neucleosynthesis

    Science.gov (United States)

    Kawagoe, Shiou; Suzuki, H.; Sumiyoshi, K.; Yamada, H.; Kajino, T.

    We try to limit the neutrino oscillation parameters from the supernova neutrinos by studying the MSW matter effect. The supernova neutrinos are generated in the core and propagate through the envelope. It is pointed out that shock wave propagation has strong influences on the supernova neutrino oscillation through the change of density profile. Using an implicit Lagrangian code for general relativistic spherical hydrodynamics (Ya- mada,1997), we succeeded in calculating propagation of shock waves which are generated by adiabatic collapse of iron cores and pass into the stellar envelopes for more than ˜5s. We examined how the influence of the shock wave appears in the neutrino spectrum, using density profile obtained in our calculation. We confirmed that the influence of the shock wave appears from low-energy side and moves toward high-energy side according to the shock propagation. In addition, we calculated the neutrino signal that will be observed on the earth, and found that this manner of the neutrino signal depends remarkably on the neutrino oscillation parameters. There- fore, there is a possibility of constraining the neutrino oscillation parameters from the supernova neutrino spectrum. Moreover, there is a possibility of finding the influence on the nucleosynthesis by changing the neutrino spectrum.

  3. Shock Wave Diffraction Phenomena around Slotted Splitters

    Directory of Open Access Journals (Sweden)

    Francesca Gnani

    2015-01-01

    Full Text Available In the field of aerospace engineering, the study of the characteristics of vortical flows and their unsteady phenomena finds numerous engineering applications related to improvements in the design of tip devices, enhancement of combustor performance, and control of noise generation. A large amount of work has been carried out in the analysis of the shock wave diffraction around conventional geometries such as sharp and rounded corners, but the employment of splitters with lateral variation has hardly attracted the attention of researchers. The investigation of this phenomenon around two-dimensional wedges has allowed the understanding of the basic physical principles of the flow features. On the other hand, important aspects that appear in the third dimension due to the turbulent nature of the vortices are omitted. The lack of studies that use three-dimensional geometries has motivated the current work to experimentally investigate the evolution of the shock wave diffraction around two splitters with spike-shaped structures for Mach numbers of 1.31 and 1.59. Schlieren photography was used to obtain an insight into the sequential diffraction processes that take place in different planes. Interacting among them, these phenomena generate a complicated turbulent cloud with a vortical arrangement.

  4. Shock-wave therapy in scapularhumeral periarthritis

    Directory of Open Access Journals (Sweden)

    Bulakh О.А.

    2014-12-01

    Full Text Available The aim of the present study was to determine the effectiveness of extracorporeal shock wave therapy in treating shoulder-scapular periarthritis. Material and methods. Survey and treatment of 30 patients of 45-67 years old with the diagnosis: shoulder periarthritis (7 women and 23 men. Age of the disease ranged from 1 month to 5 years. All patients were conducted x-ray examination of the cervical spine and the shoulder joint (radiography and/or MRI. To determine the pain activity the Visual analogue scale was used, Dowborn's test, test WAM. Results. The characteristic feature of the shoulder periarthritis is positive Dowborn's symptom: when rotating the shoulder inside (internal rotation and the side of her moves up to 450-900 there was a pain in the shoulder joint (100% of patients. Conclusion. The appointment of a medical course of ESWT enhances functionality and adaptive responses in patients with shoulder-dorsal periartritom, and may be the method of choice of tactics therapy treatment of patients of this profile. The shock wave therapy is delayed effect. All patients received the ESWT, observed devolution of pain, to a minimum of 6 months to recommend re courses of therapy with a frequency of no more than 2 times a year.

  5. Charge-Confining Gravitational Electrovacuum Shock Wave

    CERN Document Server

    Guendelman, Eduardo; Pacheva, Svetlana

    2013-01-01

    In previous publications we have extensively studied spherically symmetric solutions of gravity coupled to a non-standard type of non-linear electrodynamics containing a square root of the ordinary Maxwell Lagrangian (the latter is known to yield QCD-like confinement in flat space-time). A class of these solutions describe non-standard black holes of Reissner-Nordstroem-(anti-)-de-Sitter type with an additional constant radial vacuum electric field, in particular, a non-asymptotically flat Reissner-Nordstroem-type black hole. Here we study the ultra-relativistic boost (Aichelburg-Sexl-type) limit of the latter and show that, unlike the ordinary Reissner-Nordstroem case, we obtain a gravitational electrovacuum shock wave as a result of the persistence of the gauge field due to the "square-root" Maxwell Lagrangian term. Next, we show that this gravitational electrovacuum shock wave confines charged test particles (both massive and massless) within a finite distance from its front.

  6. Smart structures for shock wave attenuation using ER inserts

    Science.gov (United States)

    Kim, Jaehwan; Kim, Jung-Yup; Choi, Seung-Bok; Kim, Kyung-Su

    2001-08-01

    This Paper demonstrates the possibility of shock wave attenuation propagating through a smart structure that incorporates ER insert. The wave transmission of ER inserted beam is theoretically derived using Mead & Markus model and the theoretical results are compared with the finite element analysis results. To experimentally verify the shock wave attenuation, ER insert in an aluminum plate is made and two piezoceramic disks are used as transmitter and receiver of the wave. The transmitter sends a sine pulse signal such that a component of shock wave travels through the plate structure and the receiver gets the transmitted wave signal. Wave propagation of the ER insert can be adjusted by changing the applied electric field on the ER insert. Details of the experiment are addressed and the possibility of shock wave attenuation is experimentally verified. This kind of smart structure can be used for warship and submarine hull structures to protect fragile and important equipment.

  7. Planar shock wave sliding over a water layer

    Science.gov (United States)

    Rodriguez, V.; Jourdan, G.; Marty, A.; Allou, A.; Parisse, J.-D.

    2016-08-01

    In this work, we conduct experiments to study the interaction between a horizontal free water layer and a planar shock wave that is sliding over it. Experiments are performed at atmospheric pressure in a shock tube with a square cross section (200× 200 mm^2) for depths of 10, 20, and 30 mm; a 1500-mm-long water layer; and two incident planar shock waves having Mach numbers of 1.11 and 1.43. We record the pressure histories and high-speed visualizations to study the flow patterns, surface waves, and spray layers behind the shock wave. We observe two different flow patterns with ripples formed at the air-water interface for the weaker shock wave and the dispersion of a droplet mist for the stronger shock wave. From the pressure signals, we extract the delay time between the arrival of the compression wave into water and the shock wave in air at the same location. We show that the delay time evolves with the distance traveled over the water layer, the depth of the water layer, and the Mach number of the shock wave.

  8. Multiple structure of a laser-induced underwater shock wave

    CERN Document Server

    Tagawa, Yoshiyuki; Hayasaka, Keisuke; Kameda, Masaharu

    2015-01-01

    The structure of a laser-induced underwater shock wave is examined. Plasma formation, shock-wave expansion, and temporal evolution of shock pressure are observed simultaneously using a combined measurement system that obtains high-resolution nanosecond-order image sequences. In contrast to a well-known spherical-shock model, these detailed measurements reveal a non-spherically-symmteric distribution of pressure peak for a wide range of experimental parameters. The structure is determined to be a collection of multiple spherical shocks originated from elongated plasmas.

  9. Simulations of shock wave propagation in heterogeneous solids

    Science.gov (United States)

    Hertzsch, Jan-Martin; Ivanov, Boris A.; Kenkmann, Thomas

    2002-11-01

    Studies of shock wave propagation in heterogeneous materials are important for the interpretation of impact deformation and impact metamorphism of natural rocks. Reflection, refraction, and interference of shock waves caused by inhomogeneities lead to localised concentrations of pressure, temperature, and deformation rate, and in some cases to phase transitions. We have simulated numerically the shock compression of complex media in selected geometries with the aim of modelling shock recovery experiments and have observed reversible phase transitions in the target, shock heating alone may not be sufficient for the formation of impact melt, but localised shear at material boundaries results in considerable temperature increase which makes partial melting possible.

  10. Similarity solution of the shock wave propagation in water

    Directory of Open Access Journals (Sweden)

    Muller M.

    2007-11-01

    Full Text Available This paper presents the possibility of calculation of propagation of a shock wave generated during the bubble collapse in water including the dissipation effect. The used semi-empirical model is based on an assumption of similarity between the shock pressure time profiles in different shock wave positions. This assumption leads to a system of two ordinary differential equations for pressure jump and energy at the shock front. The NIST data are used for the compilation of the equation of state, which is applied to the calculation of the shock wave energy dissipation. The initial conditions for the system of equations are obtained from the modified method of characteristics in the combination with the differential equations of cavitation bubble dynamics, which considers viscous compressible liquid with the influence of surface tension. The initial energy of the shock wave is estimated from the energy between the energies of the bubble growth to the first and second maximum bubble radii.

  11. Shock waves in fluid-filled distensible tubes.

    Science.gov (United States)

    Rudinger, G

    1980-02-01

    Flow of a liquid through distensible tubes is of interest primarily in biological systems, and some properties of shock waves in such tubes are discussed. In shock-fixed coordinates, these flows are steady, and the shock is associated with an increase of pressure and cross-sectional area. Shock transition is analyzed for two flow models, namely, immediate flow separation, when the flow enters the shock zone, and no separation. Shock properties are expressed in terms of the speed index (ratio of the velocity of the shock to that of a small-amplitude wave) and dissipation (loss of total pressure). Examples are worked out for the thoracic aorta of an anesthetized dog, a perfectly elastic tube, and a partially collapsed tube. Appreciable differences in shock velocity and dissipation result if either flow separation or no separation is assumed.

  12. Unfocused Extracorporeal Shock Waves Induce Anabolic Effects in Rat Bone

    NARCIS (Netherlands)

    O.P. van der Jagt (Olav); T.M. Piscaer (Tom); W. Schaden (Wolfgang); J. Li; N. Kops (Nicole); H. Jahr (Holger); J.C. van der Linden (Jacqueline); J.H. Waarsing (Jan); J.A.N. Verhaar (Jan); M. de Jong (Marion); H.H. Weinans (Harrie)

    2011-01-01

    textabstractAbstract. BACKGROUND: Extracorporeal shock waves are known to stimulate the differentiation of mesenchymal stem cells toward osteoprogenitors and induce the expression of osteogenic-related growth hormones. The aim of this study was to investigate if and how extracorporeal shock waves af

  13. Unfocused Extracorporeal Shock Waves Induce Anabolic Effects in Rat Bone

    NARCIS (Netherlands)

    O.P. van der Jagt (Olav); T.M. Piscaer (Tom); W. Schaden (Wolfgang); J. Li; N. Kops (Nicole); H. Jahr (Holger); J.C. van der Linden (Jacqueline); J.H. Waarsing (Jan); J.A.N. Verhaar (Jan); M. de Jong (Marion); H.H. Weinans (Harrie)

    2011-01-01

    textabstractAbstract. BACKGROUND: Extracorporeal shock waves are known to stimulate the differentiation of mesenchymal stem cells toward osteoprogenitors and induce the expression of osteogenic-related growth hormones. The aim of this study was to investigate if and how extracorporeal shock waves

  14. Extracorporeal shock wave lithotripsy of biliary and pancreatic stones

    NARCIS (Netherlands)

    R. den Toom (Rene)

    1993-01-01

    textabstractThe aim of the study was to answer the following questions: Is extracorporeal shock wave lithotripsy for gallbladder stones a safe and effective therapy? (Chapter 2) Is simultaneous treatment with extracorporeal shock wave lithotripsy and the solvent methyl te.rt-butyl ether feasible, sa

  15. Shock Mechanism Analysis and Simulation of High-Power Hydraulic Shock Wave Simulator

    Directory of Open Access Journals (Sweden)

    Xiaoqiu Xu

    2017-01-01

    Full Text Available The simulation of regular shock wave (e.g., half-sine can be achieved by the traditional rubber shock simulator, but the practical high-power shock wave characterized by steep prepeak and gentle postpeak is hard to be realized by the same. To tackle this disadvantage, a novel high-power hydraulic shock wave simulator based on the live firing muzzle shock principle was proposed in the current work. The influence of the typical shock characteristic parameters on the shock force wave was investigated via both theoretical deduction and software simulation. According to the obtained data compared with the results, in fact, it can be concluded that the developed hydraulic shock wave simulator can be applied to simulate the real condition of the shocking system. Further, the similarity evaluation of shock wave simulation was achieved based on the curvature distance, and the results stated that the simulation method was reasonable and the structural optimization based on software simulation is also beneficial to the increase of efficiency. Finally, the combination of theoretical analysis and simulation for the development of artillery recoil tester is a comprehensive approach in the design and structure optimization of the recoil system.

  16. Biomechanical and Biochemical Cellular Response Due to Shock Waves

    Science.gov (United States)

    2008-12-01

    using shock- wave-induced cavitation . Ultrasound in Medicine and Biology, 29, 1769-1776. Lew, H. L., J. H. Poole, S. Alvarez, and W. Moore, 2005...sheets of adipose derived stem cells to shock waves. A key guideline in the experimental design was to suppress cavitation . To this end we...shock-exposed cells and controls. We attribute this to the absence of cavitation . Time-resolved gene expression revealed that a large

  17. Shock wave of vapor-liquid two-phase flow

    Institute of Scientific and Technical Information of China (English)

    Liangju ZHAO; Fei WANG; Hong GAO; Jingwen TANG; Yuexiang YUAN

    2008-01-01

    The shock wave of vapor-liquid two-phase flow in a pressure-gain steam injector is studied by build-ing a mathematic model and making calculations. The results show that after the shock, the vapor is nearly com-pletely condensed. The upstream Mach number and the volume ratio of vapor have a great effect on the shock. The pressure and Mach number of two-phase shock con-form to the shock of ideal gas. The analysis of available energy shows that the shock is an irreversible process with entropy increase.

  18. Dispersive shock waves in nematic liquid crystals

    Science.gov (United States)

    Smyth, Noel F.

    2016-10-01

    The propagation of coherent light with an initial step intensity profile in a nematic liquid crystal is studied using modulation theory. The propagation of light in a nematic liquid crystal is governed by a coupled system consisting of a nonlinear Schrödinger equation for the light beam and an elliptic equation for the medium response. In general, the intensity step breaks up into a dispersive shock wave, or undular bore, and an expansion fan. In the experimental parameter regime for which the nematic response is highly nonlocal, this nematic bore is found to differ substantially from the standard defocusing nonlinear Schrödinger equation structure due to the effect of the nonlocality of the nematic medium. It is found that the undular bore is of Korteweg-de Vries equation-type, consisting of bright waves, rather than of nonlinear Schrödinger equation-type, consisting of dark waves. In addition, ahead of this Korteweg-de Vries bore there can be a uniform wavetrain with a short front which brings the solution down to the initial level ahead. It is found that this uniform wavetrain does not exist if the initial jump is below a critical value. Analytical solutions for the various parts of the nematic bore are found, with emphasis on the role of the nonlocality of the nematic medium in shaping this structure. Excellent agreement between full numerical solutions of the governing nematicon equations and these analytical solutions is found.

  19. The Configuration of Shock Wave Reflection for the TSD Equation

    Institute of Scientific and Technical Information of China (English)

    Li WANG

    2013-01-01

    In this paper,we mainly study the nonlinear wave configuration caused by shock wave reflection for the TSD (Transonic Small Disturbance) equation and specify the existence and nonexistence of various nonlinear wave configurations.We give a condition under which the solution of the RR (Regular reflection) for the TSD equation exists.We also prove that there exists no wave configuration of shock wave reflection for the TSD equation which consists of three or four shock waves.In phase space,we prove that the TSD equation has an IR (Irregular reflection) configuration containing a centered simple wave.Furthermore,we also prove the stability of RR configuration and the wave configuration containing a centered simple wave by solving a free boundary value problem of the TSD equation.

  20. Plasma Shock Wave Modification Experiments in a Temperature Compensated Shock Tube

    Science.gov (United States)

    Vine, Frances J.; Mankowski, John J.; Saeks, Richard E.; Chow, Alan S.

    2003-01-01

    A number of researchers have observed that the intensity of a shock wave is reduced when it passes through a weakly ionized plasma. While there is little doubt that the intensity of a shock is reduced when it propagates through a weakly ionized plasma, the major question associated with the research is whether the reduction in shock wave intensity is due to the plasma or the concomitant heating of the flow by the plasma generator. The goal of this paper is to describe a temperature compensated experiment in a "large" diameter shock tube with an external heating source, used to control the temperature in the shock tube independently of the plasma density.

  1. [Extracorporeal shock-wave therapy. Experimental basis, clinical application].

    Science.gov (United States)

    Rompe, J D; Küllmer, K; Vogel, J; Eckardt, A; Wahlmann, U; Eysel, P; Hopf, C; Kirkpatrick, C J; Bürger, R; Nafe, B

    1997-03-01

    The purpose of our studies was to investigate experimentally the dose-dependent effects of extracorporeal shock waves on tendon and bone and to unveil therapeutic possibilities in tendinopathies and pseudarthroses. In animal experiments, both positive and negative influences were exerted by shock waves, depending on the initial situation and on the power of the applied shock waves. In prospective clinical trials positive effects were found in the treatment of persistent tennis elbow, plantar fasciitis, calcifying tendinitis, and pseudarthrosis. Our data show that extracorporeal shock waves may provide analgesic, resorptive and osteo-inductive reactions with nearly no side effects. However, the high cost of apparatus and staff prevents a routine application. Extracorporeal shock waves thus remain a last alternative before the indication is made for an operative procedure.

  2. THE EFFECTS OF AREA CONTRACTION ON SHOCK WAVE STRENGTH AND PEAK PRESSURE IN SHOCK TUBE

    Directory of Open Access Journals (Sweden)

    A. M. Mohsen

    2012-06-01

    Full Text Available This paper presents an experimental investigation into the effects of area contraction on shock wave strength and peak pressure in a shock tube. The shock tube is an important component of the short duration, high speed fluid flow test facility, available at the Universiti Tenaga Nasional (UNITEN, Malaysia. The area contraction was facilitated by positioning a bush adjacent to the primary diaphragm section, which separates the driver and driven sections. Experimental measurements were performed with and without the presence of the bush, at various diaphragm pressure ratios, which is the ratio of air pressure between the driver (high pressure and driven (low pressure sections. The instantaneous static pressure variations were measured at two locations close to the driven tube end wall, using high sensitivity pressure sensors, which allow the shock wave strength, shock wave speed and peak pressure to be analysed. The results reveal that the area contraction significantly reduces the shock wave strength, shock wave speed and peak pressure. At a diaphragm pressure ratio of 10, the shock wave strength decreases by 18%, the peak pressure decreases by 30% and the shock wave speed decreases by 8%.

  3. Viscous Shear Layers Formed by Non-Bifurcating Shock Waves in Shock-Tubes

    Science.gov (United States)

    Grogan, Kevin; Ihme, Matthias

    2015-11-01

    Shock-tubes are test apparatuses that are used extensively for chemical kinetic measurements. Under ideal conditions, shock-tubes provide a quiescent region behind a reflected shock wave where combustion may take place without complications arising from gas-dynamic effects. However, due to the reflected shock wave encountering a boundary layer, significant inhomogeneity may be introduced into the test region. The bifurcation of the reflected shock-wave is well-known to occur under certain conditions; however, a viscous shear layer may form behind a non-bifurcating reflected shock wave as well and may affect chemical kinetics and ignition of certain fuels. The focus of this talk is on the development of the viscous shear layer and the coupling to the ignition in the regime corresponding to the negative temperature conditions.

  4. Characteristics of Spherical Shock Wave and Circular Pulse Jet Generated by Discharge of Propagating Shock Wave at Open End of Tube

    Institute of Scientific and Technical Information of China (English)

    Tsukasa Irie; Tsuyoshi Yasunobu; Hideo Kashimura; Toshiaki Setoguchi; Kazuyasu Matsuo

    2003-01-01

    When the shock wave propagating in the straight circular tube reaches at the open end, the impulsive wave is generated by the emission of a shock wave from an open end, and unsteady pulse jet is formed near the open end behind the impulsive wave under the specific condition. The pulse jet transits to spherical shock wave with the increase in the strength of shock wave. The strength is dependent on the Mach number of shock wave, which attenuates by propagation distance from the open end. In this study, the mechanism of generating the unsteady pulse jet, the characteristics of the pressure distribution in the flow field and the emission of shock wave from straight circular tube which has the infinite flange at open end are analyzed numerically by the TVD method. Strength of spherical shock wave, relation of shock wave Mach number, distance decay of spherical shock wave and directional characteristics are clarified.

  5. Extracorporeal shock wave therapy (ESWT) in urology

    DEFF Research Database (Denmark)

    Fojecki, Grzegorz Lukasz; Thiessen, Stefan; Osther, Palle Jörn Sloth

    2017-01-01

    PURPOSE: The objective was to evaluate high-level evidence studies of extracorporeal shock wave therapy (ESWT) for urological disorders. METHODS: We included randomized controlled trials reporting outcomes of ESWT in urology. Literature search on trials published in English using EMBASE, Medline...... and PubMed was carried out. The systematic review was performed according to PRISMA guidelines. RESULTS: We identified 10 trials on 3 urological indications. Two of 3 trials on Peyronie's disease (PD) involving 238 patients reported improvement in pain; however, no clinical significant changes in penile......i) responders in 2 of 4 trials and 3 of 4 trials, respectively. Three studies on chronic pelvic pain (CPP) engaging 200 men reported positive changes in National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI). There was considerable heterogeneity between trials both with regard...

  6. Two-dimensional dispersive shock waves in dissipative optical media

    CERN Document Server

    Kartashov, Yaroslav V

    2013-01-01

    We study generation of two-dimensional dispersive shock waves and oblique dark solitons upon interaction of tilted plane waves with negative refractive index defects embedded into defocusing material with linear gain and two-photon absorption. Different evolution regimes are encountered including the formation of well-localized disturbances for input tilts below critical one, and generation of extended shock waves containing multiple intensity oscillations in the "upstream" region and gradually vanishing oblique dark solitons in "downstream" region for input tilts exceeding critical one. The generation of stable dispersive shock waves is possible only below certain critical defect strength.

  7. The influence of incident shock Mach number on radial incident shock wave focusing

    Directory of Open Access Journals (Sweden)

    Xin Chen

    2016-04-01

    Full Text Available Experiments and numerical simulations were carried out to investigate radial incident shock focusing on a test section where the planar incident shock wave was divided into two identical ones. A conventional shock tube was used to generate the planar shock. Incident shock Mach number of 1.51, 1.84 and 2.18 were tested. CCD camera was used to obtain the schlieren photos of the flow field. Third-order, three step strong-stability-preserving (SSP Runge-Kutta method, third-order weighed essential non-oscillation (WENO scheme and adaptive mesh refinement (AMR algorithm were adopted to simulate the complicated flow fields characterized by shock wave interaction. Good agreement between experimental and numerical results was observed. Complex shock wave configurations and interactions (such as shock reflection, shock-vortex interaction and shock focusing were observed in both the experiments and numerical results. Some new features were observed and discussed. The differences of structure of flow field and the variation trends of pressure were compared and analyzed under the condition of different Mach numbers while shock wave focusing.

  8. Sharp low-energy feature in single-particle spectra due to forward scattering in d-wave cuprate superconductors.

    Science.gov (United States)

    Hong, Seung Hwan; Bok, Jin Mo; Zhang, Wentao; He, Junfeng; Zhou, X J; Varma, C M; Choi, Han-Yong

    2014-08-01

    There is an enormous interest in the renormalization of the quasiparticle (qp) dispersion relation of cuprate superconductors both below and above the critical temperature T_{c} because it enables the determination of the fluctuation spectrum to which the qp's are coupled. A remarkable discovery by angle-resolved photoemission spectroscopy (ARPES) is a sharp low-energy feature (LEF) in qp spectra well below the superconducting energy gap but with its energy increasing in proportion to T_{c} and its intensity increasing sharply below T_{c}. This unexpected feature needs to be reconciled with d-wave superconductivity. Here, we present a quantitative analysis of ARPES data from Bi_{2}Sr_{2}CaCu_{2}O_{8+δ} (Bi2212) using Eliashberg equations to show that the qp scattering rate due to the forward scattering impurities far from the Cu-O planes is modified by the energy gap below T_{c} and shows up as the LEF. This is also a necessary step to analyze ARPES data to reveal the spectrum of fluctuations promoting superconductivity.

  9. Design of an 81.25 MHz continuous-wave radio-frequency quadrupole accelerator for Low Energy Accelerator Facility

    Science.gov (United States)

    Ma, Wei; Lu, Liang; Xu, Xianbo; Sun, Liepeng; Zhang, Zhouli; Dou, Weiping; Li, Chenxing; Shi, Longbo; He, Yuan; Zhao, Hongwei

    2017-03-01

    An 81.25 MHz continuous wave (CW) radio frequency quadrupole (RFQ) accelerator has been designed for the Low Energy Accelerator Facility (LEAF) at the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). In the CW operating mode, the proposed RFQ design adopted the conventional four-vane structure. The main design goals are providing high shunt impendence with low power losses. In the electromagnetic (EM) design, the π-mode stabilizing loops (PISLs) were optimized to produce a good mode separation. The tuners were also designed and optimized to tune the frequency and field flatness of the operating mode. The vane undercuts were optimized to provide a flat field along the RFQ cavity. Additionally, a full length model with modulations was set up for the final EM simulations. Following the EM design, thermal analysis of the structure was carried out. In this paper, detailed EM design and thermal simulations of the LEAF-RFQ will be presented and discussed. Structure error analysis was also studied.

  10. Dispersive radiation induced by shock waves in passive resonators.

    Science.gov (United States)

    Malaguti, Stefania; Conforti, Matteo; Trillo, Stefano

    2014-10-01

    We show that passive Kerr resonators pumped close to zero dispersion wavelengths on the normal dispersion side can develop the resonant generation of linear waves driven by cavity (mixed dispersive-dissipative) shock waves. The resonance mechanism can be successfully described in the framework of the generalized Lugiato-Lefever equation with higher-order dispersive terms. Substantial differences with radiation from cavity solitons and purely dispersive shock waves dispersion are highlighted.

  11. Shock wave diffraction and reflection around a dusty square cavity

    Institute of Scientific and Technical Information of China (English)

    王柏懿; 王超; 戚隆溪

    2001-01-01

    The diffraction and reflection of planar shock wave around a dusty square cavity is investigated nuerically, which is embedded in the flat bottom surface of a two-dimensional channel, and the induced gas-particle twophase flow. The wave patterns at different times are obtained for three different values of the particle diameter. The computational results show that the existence of particles affects appreciably the shock wave diffraction and cavity flow.

  12. Cosmological shock waves: clues to the formation history of haloes

    CERN Document Server

    Planelles, Susana

    2012-01-01

    Shock waves developed during the formation and evolution of cosmic structures encode crucial information on the hierarchical formation of the Universe. We analyze an Eulerian AMR hydro + N-body simulation in a $\\Lambda$CDM cosmology focused on the study of cosmological shock waves. The combination of a shock-capturing algorithm together with the use of a halo finder allows us to study the morphological structures of the shock patterns, the statistical properties of shocked cells, and the correlations between the cosmological shock waves appearing at different scales and the properties of the haloes harbouring them. The shocks in the simulation can be split into two broad classes: internal weak shocks related with evolutionary events within haloes, and external strong shocks associated with large-scale events. The shock distribution function contains information on the abundances and strength of the different shocks, and it can be fitted by a double power law with a break in the slope around a Mach number of 2...

  13. Shock-wave therapy for tennis and golfer's elbow--1 year follow-up.

    Science.gov (United States)

    Krischek, O; Hopf, C; Nafe, B; Rompe, J D

    1999-01-01

    Thirty patients with chronic medial epicondylitis were treated with low-energy shock waves. They received 500 impulses of 0.08 mJ/mm2 three times at weekly intervals. At 1 year follow-up examinations were performed. According to the Verhaar criteria, only seven patients reached excellent or good results. In eight cases a fair outcome was recorded, and in 14 patients the outcome was poor. Only six patients were satisfied with the treatment. The average relief of pain was 32%. These data were significantly worse than for identically treated patients with chronic tennis elbow. Thus, the question arises as to whether extracorporal shock-wave therapy is indicated in medial epicondylitis.

  14. Interaction of a swept shock wave and a supersonic wake

    Science.gov (United States)

    He, G.; Zhao, Y. X.; Zhou, J.

    2017-03-01

    The interaction of a swept shock wave and a supersonic wake has been studied. The swept shock wave is generated by a swept compression sidewall, and the supersonic wake is generated by a wake generator. The flow field is visualized with the nanoparticle-based planar laser scattering method, and a supplementary numerical simulation is conducted by solving the Reynolds-averaged Navier-Stokes equations. The results show that the pressure rise induced by the swept shock wave can propagate upstream in the wake, which makes the location where vortices are generated move upstream, thickens the laminar section of the wake, and enlarges the generated vortices. The wake is swept away from the swept compression sidewall by the pressure gradient of the swept shock wave. This pressure gradient is not aligned with the density gradient of the supersonic wake, so the baroclinic torque generates streamwise vorticity and changes the distribution of the spanwise vorticity. The wake shock is curved, so the flow downstream of it is non-uniform, leaving the swept shock wave being distorted. A three-dimensional Mach disk structure is generated when the wake shock interacts with the swept shock wave.

  15. Interaction of a swept shock wave and a supersonic wake

    Science.gov (United States)

    He, G.; Zhao, Y. X.; Zhou, J.

    2017-09-01

    The interaction of a swept shock wave and a supersonic wake has been studied. The swept shock wave is generated by a swept compression sidewall, and the supersonic wake is generated by a wake generator. The flow field is visualized with the nanoparticle-based planar laser scattering method, and a supplementary numerical simulation is conducted by solving the Reynolds-averaged Navier-Stokes equations. The results show that the pressure rise induced by the swept shock wave can propagate upstream in the wake, which makes the location where vortices are generated move upstream, thickens the laminar section of the wake, and enlarges the generated vortices. The wake is swept away from the swept compression sidewall by the pressure gradient of the swept shock wave. This pressure gradient is not aligned with the density gradient of the supersonic wake, so the baroclinic torque generates streamwise vorticity and changes the distribution of the spanwise vorticity. The wake shock is curved, so the flow downstream of it is non-uniform, leaving the swept shock wave being distorted. A three-dimensional Mach disk structure is generated when the wake shock interacts with the swept shock wave.

  16. Shock Wave Profiles in Glass Reinforced Polyester

    Science.gov (United States)

    Boteler, J. Michael; Rajendran, A. M.; Grove, David

    1999-06-01

    The promise of lightweight armor which is also structurally robust is of particular importance to the Army for future combat vehicles. Fiber reinforced organic matrix composites such as Glass Reinforced Polyester (GRP) are being considered for this purpose due to their lower density and promising dynamic response. The work discussed here extends the prior work of Boteler who studied the delamination strength of GRP and Dandekar and Beaulieu who investigated the compressive and tensile strengths of GRP. In a series of shock wave experiments, the wave profile was examined as a function of propagation distance in GRP. Uniaxial strain was achieved by plate impact in the ARL 102 mm bore single-stage light gas gun. Embedded polyvinylidene flouride (PVDF) stress-rate gauges provided a stress history at three unique locations in the GRP and particle velocity history was recorded with VISAR. The use of Lagrange gauges embedded in such a manner provides a means of calculating the constitutive relationships between specific volume, stress, and particle velocity uniquely with no prior assumptions of the form of constitutive relation. The Lagrangian analysis will be discussed and compared to Lagrangian hydrocode (EPIC) results employing a model to describe the viscoelastic response of the composite material in one-dimension.

  17. Shock wave profiles in polymer matrix composite

    Science.gov (United States)

    Boteler, J. Michael; Rajendran, A. M.; Grove, David

    2000-04-01

    The promise of lightweight armor which is also structurally robust is of particular importance to the Army for future combat vehicles. Fiber reinforced organic matrix composites such as Polymer Matrix Composite (PMC) are being considered for this purpose due to their lower density and promising dynamic response. The work discussed here extends the prior work of Boteler who studied the delamination strength of PMC and Dandekar and Beaulieu who investigated the compressive and tensile strengths of PMC. In a series of shock wave experiments, the wave profile was examined as a function of propagation distance in PMC. Uniaxial strain was achieved by symmetric plate impact in the ARL 102 mm bore single-stage light gas gun. Embedded polyvinylidene flouride (PVDF) stress-rate gauges provided a stress history at three unique locations in the PMC and particle velocity history was recorded with VISAR. All stress data was compared to a Lagrangian hydrocode (EPIC) employing a model to describe the viscoelastic response of the composite material in one-dimension. The experimental stress histories displayed attenuation and loading properties in good agreement with model predictions. However, the unloading was observed to be markedly different than the hydrocode simulations. These results are discussed.

  18. Shock wave loading of a magnetic guide

    Science.gov (United States)

    Kindt, L.

    2011-10-01

    velocities and a shock wave is created between the two velocity regions. In order to conserve number of particle, momentum and enthalpy the density of the atomic beam passing through the shock wave must increase. We have build such a shock wave in an atomic beam and observed the density increase due to this. As an extra feature having a subsonic beam on a downward slope adds an extra density increase due to gravitational compression. Loading ultra cold atoms into a 3D trap from the dense subsonic beam overcomes the problem with 2D cooling and thermal conductivity. This was done and evaporative cooling was applied creating an unprecedented large number rubidium BEC.

  19. Exact focusing of extracorporeal shock wave therapy for calcifying tendinopathy.

    Science.gov (United States)

    Haake, Michael; Deike, Barbara; Thon, Alexander; Schmitt, Jan

    2002-04-01

    A controlled prospective randomized study was designed to analyze the effect of extracorporeal shock wave therapy on calcifying tendinopathy of the shoulder focused on the calcified area or the origin of the supraspinatus tendon. Fifty patients were included in the study and were treated with a Storz Minilith Sl-1 shock wave generator. The first group of patients received 4000 impulses (positive energy flux density, 0.78 mJ/mm2) in two treatment sessions after receiving local anesthesia at the origin of the supraspinatus tendon. Patients in the second group received extracorporeal shock wave therapy at the calcified area. Follow-ups were done 12 weeks and 1 year after treatment by an independent observer. An increase of function and a reduction of pain occurred in both groups. Statistical analyses showed a significant superiority of extracorporeal shock wave application at the calcified area in the primary end point (Constant and Murley score). Therefore, exact fluoroscopic focusing of extracorporeal shock wave therapy at the calcific deposit for treatment of calcifying tendinopathy of the supraspinatus muscle is recommended. Based on these results, extracorporeal shock wave application should be focused fluoroscopically with appropriate shock wave generators.

  20. Detecting shock waves in cosmological smoothed particle hydrodynamics simulations

    CERN Document Server

    Pfrommer, C; Ensslin, T A; Jubelgas, M; Pfrommer, Christoph; Springel, Volker; Ensslin, Torsten A.; Jubelgas, Martin

    2006-01-01

    We develop a formalism for the identification and accurate estimation of the strength of structure formation shocks during cosmological smoothed particle hydrodynamics simulations. Shocks not only play a decisive role for the thermalization of gas in virialising structures but also for the acceleration of relativistic cosmic rays (CRs) through diffusive shock acceleration. Our formalism is applicable both to ordinary non-relativistic thermal gas, and to plasmas composed of CRs and thermal gas. To this end, we derive an analytical solution to the one-dimensional Riemann shock tube problem for a composite plasma of CRs and thermal gas. We apply our methods to study the properties of structure formation shocks in high-resolution hydrodynamic simulations of the LCDM model. We find that most of the energy is dissipated in weak internal shocks with Mach numbers M~2 which are predominantly central flow shocks or merger shock waves traversing halo centres. Collapsed cosmological structures are surrounded by external ...

  1. Shock Waves in a Bose-Einstein Condensate

    Science.gov (United States)

    Kulikov, Igor; Zak, Michail

    2005-01-01

    A paper presents a theoretical study of shock waves in a trapped Bose-Einstein condensate (BEC). The mathematical model of the BEC in this study is a nonlinear Schroedinger equation (NLSE) in which (1) the role of the wave function of a single particle in the traditional Schroedinger equation is played by a space- and time-dependent complex order parameter (x,t) proportional to the square root of the density of atoms and (2) the atoms engage in a repulsive interaction characterized by a potential proportional to | (x,t)|2. Equations that describe macroscopic perturbations of the BEC at zero temperature are derived from the NLSE and simplifying assumptions are made, leading to equations for the propagation of sound waves and the transformation of sound waves into shock waves. Equations for the speeds of shock waves and the relationships between jumps of velocity and density across shock fronts are derived. Similarities and differences between this theory and the classical theory of sound waves and shocks in ordinary gases are noted. The present theory is illustrated by solving the equations for the example of a shock wave propagating in a cigar-shaped BEC.

  2. First experience with a modified Siemens Lithostar shock wave system.

    Science.gov (United States)

    Volmer, K D; Köhler, G; Folberth, W; Planz, K

    1991-01-01

    A Siemens Lithostar shock wave system was modified and investigated clinically. The modified system yields increased focal pressure and energy density. The first clinical experience in renal calculi shows a significant reduction in shock wave numbers per treatment. Higher energy output enables better treatment results for difficult stones such as staghorn and infections calculi. Despite the higher energy output more than 90% of treatments could be performed without anesthesia or analgesia. No significant side effects could be detected. The service life of the modified shock wave system increased by a factor of two.

  3. Shock Wave Induced Separation Control by Streamwise Vortices

    Institute of Scientific and Technical Information of China (English)

    Ryszard SZWABA

    2005-01-01

    Control of shock wave and boundary layer interaction finds still a lot of attention. Methods of this interaction control have been especially investigated in recent decade. This research was mostly concerned with flows without separation. However, in many applications shock waves induce separation often leads to strong unsteady effects. In this context it is proposed to use streamwise vortices for the interaction control. The results of experimental investigations are presented here. The very promising results were obtained, meaning that the incipient separation was postponed and the separation size was reduced for the higher Mach numbers. The decrease of the RMS of average shock wave oscillation was also achieved.

  4. Configuration of Shock Waves in Two-Dimensional Overexpanded Jets

    Institute of Scientific and Technical Information of China (English)

    Masashi Kashitani; Yutaka Yamaguchi; Yoshiaki Miyazato; Mitsuharu Masuda; Kazuyasu Matsuo

    2003-01-01

    An experimental and analytical study has been carried out to obtain the clear understanding of a shock wave transition associated with a steady two-dimensional overexpanded flow. Two-dimensional inviscid theory with respect to a shock wave reflection is used in the present study on the characteristic of shock waves. The results obtained from the flow analysis are compared with those obtained from flow visualizations. It is shown that in the region of regular reflection, the angle of an incident shock wave becomes lower than that calculated by two shock theory with an increment in the ratio pe/pb of the nozzle exit pressure pe to the back pressure pb. It is indicated that the configuration of shock waves in overexpanded jets is influenced by the divergent angle at the nozzle exit. Also it is shown from the flow visualization that a series of shock waves move into the nozzle inside with a decrease in pressure ratio pe/pb, even if the pe/pb is under overexpanded conditions.

  5. Whistler wave bursts upstream of the Uranian bow shock

    Science.gov (United States)

    Smith, Charles W.; Goldstein, Melvyn L.; Wong, Hung K.

    1989-01-01

    Observations of magnetic field wave bursts upstream of the Uranian bow shock are reported which were recorded prior to the inbound shock crossing. Three wave types are identified. One exhibits a broad spectral enhancement from a few millihertz to about 50 mHz and is seen from 17 to 10 hr prior to the inbound shock crossing. It is argued that these waves are whistler waves that have propagated upstream from the shock. A second wave type has a spacecraft frame frequency between 20 and 40 mHz, is seen only within or immediately upstream of the shock pedestal, is right-hand polarized in the spacecraft frame, and has a typical burst duration of 90 s. The third wave type has a spacecraft frame frequency of about 0.15 Hz, is seen exclusively within the shock pedestal, is left-hand polarized in the spacecraft frame, and has a burst duration lasting up to 4 min. It is argued that the low-frequency bursts are whistler waves with phase speed comparable to, but in excess of, the solar wind speed.

  6. Gasdynamic characteristics of toroidal shock and detonation wave converging

    Institute of Scientific and Technical Information of China (English)

    TENG; Honghui; JIANG; Zonglin

    2005-01-01

    The modified CCW relation is applied to analyzing the shock, detonation wave converging and the role of chemical reactions in the process. Results indicate that the shock wave is strengthened faster than the detonation wave in the converging at the same initial Mach number. Euler equations implemented with a detailed chemical reaction model are solved to simulate toroidal shock and detonation wave converging. Gasdynamic characteristics of the converging are investigated, including wave interaction patterns, observable discrepancies and physical phenomena behind them. By comparing wave diffractions, converging processes and pressure evolutions in the focusing area, the different effects of chemical reactions on diffracting and converging processes are discussed and the analytic conclusion is demonstrated through the observation of numerical simulations.

  7. Shock wave profiles in the burnett approximation

    Science.gov (United States)

    Uribe; Velasco; Garcia-Colin; Diaz-Herrera

    2000-11-01

    This paper is devoted to a discussion of the profiles of shock waves using the full nonlinear Burnett equations of hydrodynamics as they appear from the Chapman-Enskog solution to the Boltzmann equation. The system considered is a dilute gas composed of rigid spheres. The numerical analysis is carried out by transforming the hydrodynamic equations into a set of four first-order equations in four dimensions. We compare the numerical solutions of the Burnett equations, obtained using Adam's method, with the well known direct simulation Monte Carlo method for different Mach numbers. An exhaustive mathematical analysis of the results offered here has been done mainly in connection with the existence of heteroclinic trajectories between the two stationary points located upflow and downflow. The main result of this study is that such a trajectory exists for the Burnett equations for Mach numbers greater than 1. Our numerical calculations suggest that heteroclinic trajectories exist up to a critical Mach number ( approximately 2.69) where local mathematical analysis and numerical computations reveal a saddle-node-Hopf bifurcation. This upper limit for the existence of heteroclinic trajectories deserves further clarification.

  8. Shock wave driven microparticles for pharmaceutical applications

    Science.gov (United States)

    Menezes, V.; Takayama, K.; Gojani, A.; Hosseini, S. H. R.

    2008-10-01

    Ablation created by a Q-switched Nd:Yttrium Aluminum Garnet (Nd:YAG) laser beam focusing on a thin aluminum foil surface spontaneously generates a shock wave that propagates through the foil and deforms it at a high speed. This high-speed foil deformation can project dry micro- particles deposited on the anterior surface of the foil at high speeds such that the particles have sufficient momentum to penetrate soft targets. We used this method of particle acceleration to develop a drug delivery device to deliver DNA/drug coated microparticles into soft human-body targets for pharmaceutical applications. The device physics has been studied by observing the process of particle acceleration using a high-speed video camera in a shadowgraph system. Though the initial rate of foil deformation is over 5 km/s, the observed particle velocities are in the range of 900-400 m/s over a distance of 1.5-10 mm from the launch pad. The device has been tested by delivering microparticles into liver tissues of experimental rats and artificial soft human-body targets, modeled using gelatin. The penetration depths observed in the experimental targets are quite encouraging to develop a future clinical therapeutic device for treatments such as gene therapy, treatment of cancer and tumor cells, epidermal and mucosal immunizations etc.

  9. Dispersive shock waves and modulation theory

    Science.gov (United States)

    El, G. A.; Hoefer, M. A.

    2016-10-01

    There is growing physical and mathematical interest in the hydrodynamics of dissipationless/dispersive media. Since G.B. Whitham's seminal publication fifty years ago that ushered in the mathematical study of dispersive hydrodynamics, there has been a significant body of work in this area. However, there has been no comprehensive survey of the field of dispersive hydrodynamics. Utilizing Whitham's averaging theory as the primary mathematical tool, we review the rich mathematical developments over the past fifty years with an emphasis on physical applications. The fundamental, large scale, coherent excitation in dispersive hydrodynamic systems is an expanding, oscillatory dispersive shock wave or DSW. Both the macroscopic and microscopic properties of DSWs are analyzed in detail within the context of the universal, integrable, and foundational models for uni-directional (Korteweg-de Vries equation) and bi-directional (Nonlinear Schrödinger equation) dispersive hydrodynamics. A DSW fitting procedure that does not rely upon integrable structure yet reveals important macroscopic DSW properties is described. DSW theory is then applied to a number of physical applications: superfluids, nonlinear optics, geophysics, and fluid dynamics. Finally, we survey some of the more recent developments including non-classical DSWs, DSW interactions, DSWs in perturbed and inhomogeneous environments, and two-dimensional, oblique DSWs.

  10. Investigation on shock waves stability in relativistic gas dynamics

    Directory of Open Access Journals (Sweden)

    Alexander Blokhin

    1993-05-01

    Full Text Available This paper is devoted to investigation of the linearized mixed problem of shock waves stability in relativistic gas dynamics. The problem of symmetrization of relativistic gas dynamics equations is also discussed.

  11. Shock Waves in the Treatment of Muscle Hypertonia and Dystonia

    Directory of Open Access Journals (Sweden)

    Laura Mori

    2014-01-01

    Full Text Available Since 1997, focused shock waves therapy (FSWT has been reported to be useful in the treatment of muscle hypertonia and dystonia. More recently, also radial shock wave therapy (RSWT has been successfully used to treat muscle hypertonia. The studies where FSWT and RSWT have been used to treat muscle hypertonia and dystonia are reviewed in this paper. The more consistent and long lasting results were obtained in the lower limb muscles of patients affected by cerebral palsy with both FSWT and RSWT and in the distal upper limb muscles of adult stroke patients using FSWT. The most probable mechanism of action is a direct effect of shock waves on muscle fibrosis and other nonreflex components of muscle hypertonia. However, we believe that up to now the biological effects of shock waves on muscle hypertonia and dystonia cannot be clearly separated from a placebo effect.

  12. Aspects Regarding Shock Wave Mitigation Through Different Media

    Directory of Open Access Journals (Sweden)

    Pană Iuliana Florina

    2015-12-01

    Full Text Available The main application of underwater detonation since the Second World War is to destroy military ships. Nowadays, a lot of studies are performed in order to discover a controlled and safe application of shock waves through different media. The paper presents the results of a research on a bubble curtain behaviour subjected to shock waves generated by an underwater TNT blast. The main objective was to analyze the mitigation solution of underwater explosion effects by means of gas bubbles. Simulations using ANSYS AUTODYN and explicit dynamics procedures were performed on a 3D model, in order to better understand the physical process of formation and propagation of a shock wave in the biphasic medium which represents the purpose of many researchers. The numerical simulations were performed taking into account the interaction between a shock wave and the bubble curtain considering a random distribution in space and bubble dimensions.

  13. Multi-layer protective armour for underwater shock wave mitigation

    Directory of Open Access Journals (Sweden)

    Ahmed Hawass

    2015-12-01

    The strain gauge data and displacement sensors results showed that the multi-layer plates have higher level of underwater shock wave mitigation than the triple aluminum plates with strain and deflection of nearly 50%.

  14. High-speed imaging of dynamic shock wave reflection phenomena

    CSIR Research Space (South Africa)

    Naidoo, K

    2010-09-01

    Full Text Available Dynamic shock wave reflection generated by a rapidly pitching wedge in a steady supersonic free stream has been studied with numerical simulation previously. An experimental facility was developed for the investigation of these dynamic phenomena...

  15. Particle imaging through planar shock waves and associated velocimetry errors

    NARCIS (Netherlands)

    Elsinga, G.E.; Orlicz, G.C.

    2015-01-01

    When imaging particles through a shock wave, the resulting particle image appears blurred and at the wrong location, which is referred to as a position error. Particle image doublets are observed if only part of the light scattered by a particle is deflected or reflected by the shock. These optical

  16. Grain Destruction in a Supernova Remnant Shock Wave

    Science.gov (United States)

    Raymond, John C.; Ghavamian, Parviz; Williams, Brian J.; Blair, William P.; Borkowski, Kazimierz J.; Gaetz, Terrance J.; Sankrit, Ravi

    2014-01-01

    Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants, gradually enriching the gas phase with refractory elements. We have measured emission in C IV (lambda)1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 micron and the X-ray intensity profiles. Thus these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the CIV intensity 10'' behind the shock is too high compared to the intensities at the shock and 25'' behind it. Variations in the density, hydrogen neutral fraction and the dust properties over parsec scales in the pre- shock medium limit our ability to test dust destruction models in detail.

  17. Grain Destruction in a Supernova Remnant Shock Wave

    CERN Document Server

    Raymond, John C; Williams, Brian J; Blair, William P; Borkowski, Kazimierz J; Gaetz, Terrance J; Sankrit, Ravi

    2013-01-01

    Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants, gradually enriching the gas phase with refractory elements. We have measured emission in C IV $\\lambda$1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 micron and the X-ray intensity profiles. Thus these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the CIV intensity 10" behind the shock is too high compared to the intensities at the shock and 25" behind it. Variations in the density, hydrogen neutral fraction and the dust properties over parsec scales in the pre-shock medium limit our ability to test dust destruction models in detail.

  18. Intensity improvement of shock waves induced by liquid electrical discharges

    Science.gov (United States)

    Liu, Yi; Li, Zhi-Yuan; Li, Xian-Dong; Liu, Si-Wei; Zhou, Gu-Yue; Lin, Fu-Chang

    2017-04-01

    When shock waves induced by pulsed electrical discharges in dielectric liquids are widely applied in industrial fields, it is necessary to improve the energy transfer efficiency from electrical energy to mechanical energy to improve the shock wave intensity. In order to investigate the effect of the plasma channel length created by the liquid electrical discharge on the shock wave intensity, a test stand of dielectric liquid pulsed electrical discharge is designed and constructed. The main capacitor is 3 μF, and the charging voltage is 0-30 kV. Based on the needle-needle electrode geometry with different gap distances, the intensities of shock waves corresponding to the electrical parameters, the relationship between the plasma channel length and the deposited energy, and the time-resolved observation of the plasma channel development by a high speed camera are presented and compared. The shock wave intensity is closely related to the power and energy dissipated into the plasma channel. The longer plasma channel and the quicker arc expansion can lead to a higher power and energy deposited into the plasma channel, which can activate a stronger shock wave.

  19. ON INTERACTION OF SHOCK AND SOUND WAVE (I)

    Institute of Scientific and Technical Information of China (English)

    CHENSHUXING

    1996-01-01

    This paper studies the interaction of shock and gradient wave (sound wave) of solutions to the system of inviscid isentropic gas dynamics as a model for the corresponding problems for nonlinear hyperbolic systems. The problem can be reduced to a boundary value problem in a wedged dormain, By using the method of constructing asymptotic solutions and Newton'siteration process it is proved that if a weak shock hits a gradient wave, then the grandient wave will split into two gradient waves, while the shock continuses propagating. In this paper the author reduces the problem to a standard form and constructs asymptotic solution of the problem. The existence of the genuine solution will he given in the following paper.

  20. Nonstandard analysis and jump conditions for converging shock waves

    Science.gov (United States)

    Baty, Roy S.; Farassat, F.; Tucker, Don H.

    2008-06-01

    Nonstandard analysis is an area of modern mathematics that studies abstract number systems containing both infinitesimal and infinite numbers. This article applies nonstandard analysis to derive jump conditions for one-dimensional, converging shock waves in a compressible, inviscid, perfect gas. It is assumed that the shock thickness occurs on an infinitesimal interval and the jump functions in the thermodynamic and fluid dynamic parameters occur smoothly across this interval. Predistributions of the Heaviside function and the Dirac delta measure are introduced to model the flow parameters across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the flow parameters.

  1. Ionization Front and Shock Wave Structures in Microwave Propulsion

    Science.gov (United States)

    Takahashi, M.; Miyamoto, H.; Okuno, Y.; Ohnishi, N.

    A two-dimensional finite-difference time domain code was coupled with compressible fluid calculation and a simple ionization model to reproduce microwave propagation and shock formation in atmospheric microwave discharge. Plasma filaments are driven toward the microwave source at the atmospheric pressure, and the distance between filaments is one-quarter of themicrowave wavelength as predicted in previous works. The strong shock wave is generated due to the high electron density and the large energy absorption. On the other hand, the plasma becomes diffusive at the lower pressure so that the shock wave weakens as a result of smaller energy absorption.

  2. Fractionated Repetitive Extracorporeal Shock Wave Therapy: A New Standard in Shock Wave Therapy?

    Directory of Open Access Journals (Sweden)

    Tobias Kisch

    2015-01-01

    Full Text Available Background. ESWT has proven clinical benefit in dermatology and plastic surgery. It promotes wound healing and improves tissue regeneration, connective tissue disorders, and inflammatory skin diseases. However, a single treatment session or long intervals between sessions may reduce the therapeutic effect. The present study investigated the effects of fractionated repetitive treatment in skin microcirculation. Methods. 32 rats were randomly assigned to two groups and received either fractionated repetitive high-energy ESWT every ten minutes or placebo shock wave treatment, applied to the dorsal lower leg. Microcirculatory effects were continuously assessed by combined laser Doppler imaging and photospectrometry. Results. In experimental group, cutaneous tissue oxygen saturation was increased 1 minute after the first application and until the end of the measuring period at 80 minutes after the second treatment (P<0.05. The third ESWT application boosted the effect to its highest extent. Cutaneous capillary blood flow showed a significant increase after the second application which was sustained for 20 minutes after the third application (P<0.05. Placebo group showed no statistically significant differences. Conclusions. Fractionated repetitive extracorporeal shock wave therapy (frESWT boosts and prolongs the effects on cutaneous hemodynamics. The results indicate that frESWT may provide greater benefits in the treatment of distinct soft tissue disorders compared with single-session ESWT.

  3. Shock wave consolidated MgB 2 bulk samples

    Science.gov (United States)

    Matsuzawa, Hidenori; Tamaki, Hideyuki; Ohashi, Wataru; Kakimoto, Etsuji; Dohke, Kiyotaka; Atou, Toshiyuki; Fukuoka, Kiyoto; Kikuchi, Masae; Kawasaki, Masashi; Takano, Yoshihiko

    2004-10-01

    Commercially available MgB 2 powders were consolidated into bulk samples by two different shock wave consolidation methods: underwater shock consolidation method and gun method. Resistance vs. temperature of the samples was measured by the four-terminal method for pulsed currents of up to 3 A in self-field, as well as Vickers hardness, SEM micrographs of fraction surfaces, packing densities, and X-ray diffraction patterns. These results, in comparison with cold isostatic pressed samples, indicated that the underwater shock consolidated sample was superior in grain connectivity to the others. This is probably because the underwater shock consolidation generated most anisotropic and hence high frictional, compressive, intergrain forces.

  4. Shock wave consolidated MgB{sub 2} bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzawa, Hidenori; Tamaki, Hideyuki; Ohashi, Wataru; Kakimoto, Etsuji; Dohke, Kiyotaka; Atou, Toshiyuki; Fukuoka, Kiyoto; Kikuchi, Masae; Kawasaki, Masashi; Takano, Yoshihiko

    2004-10-01

    Commercially available MgB{sub 2} powders were consolidated into bulk samples by two different shock wave consolidation methods: underwater shock consolidation method and gun method. Resistance vs. temperature of the samples was measured by the four-terminal method for pulsed currents of up to 3 A in self-field, as well as Vickers hardness, SEM micrographs of fraction surfaces, packing densities, and X-ray diffraction patterns. These results, in comparison with cold isostatic pressed samples, indicated that the underwater shock consolidated sample was superior in grain connectivity to the others. This is probably because the underwater shock consolidation generated most anisotropic and hence high frictional, compressive, intergrain forces.

  5. PENETRATION OF A SHOCK WAVE IN A FLAME FRONT

    Directory of Open Access Journals (Sweden)

    Dan PANTAZOPOL

    2009-09-01

    Full Text Available The present paper deals with the interactions between a fully supersonic flame front, situated in a supersonic two-dimensional flow of an ideal homogeneous combustible gas mixture, and an incident shock wawe, which is penetrating in the space of the hot burnt gases. A possible configuration, which was named ,,simple penetration” is examined. For the anlysis of the interference phenomena, shock polar and shock-combustion polar are used. At the same time, the paper shows the possibility to produce similar but more complicated configurations, which may contain expansion fans and reflected shock waves.

  6. Generation of Focused Shock Waves in Water for Biomedical Applications

    Science.gov (United States)

    Lukeš, Petr; Šunka, Pavel; Hoffer, Petr; Stelmashuk, Vitaliy; Beneš, Jiří; Poučková, Pavla; Zadinová, Marie; Zeman, Jan

    The physical characteristics of focused two-successive (tandem) shock waves (FTSW) in water and their biological effects are presented. FTSW were ­generated by underwater multichannel electrical discharges in a highly conductive saline solution using two porous ceramic-coated cylindrical electrodes of different diameter and surface area. The primary cylindrical pressure wave generated at each composite electrode was focused by a metallic parabolic reflector to a common focal point to form two strong shock waves with a variable time delay between the waves. The pressure field and interaction between the first and the second shock waves at the focus were investigated using schlieren photography and polyvinylidene fluoride (PVDF) shock gauge sensors. The largest interaction was obtained for a time delay of 8-15 μs between the waves, producing an amplitude of the negative pressure phase of the second shock wave down to -80 MPa and a large number of cavitations at the focus. The biological effects of FTSW were demonstrated in vitro on damage to B16 melanoma cells, in vivo on targeted lesions in the thigh muscles of rabbits and on the growth delay of sarcoma tumors in Lewis rats treated in vivo by FTSW, compared to untreated controls.

  7. Explosive-driven shock wave and vortex ring interaction with a propane flame

    Science.gov (United States)

    Giannuzzi, P. M.; Hargather, M. J.; Doig, G. C.

    2016-11-01

    Experiments were performed to analyze the interaction of an explosively driven shock wave and a propane flame. A 30 g explosive charge was detonated at one end of a 3-m-long, 0.6-m-diameter shock tube to produce a shock wave which propagated into the atmosphere. A propane flame source was positioned at various locations outside of the shock tube to investigate the effect of different strength shock waves. High-speed retroreflective shadowgraph imaging visualized the shock wave motion and flame response, while a synchronized color camera imaged the flame directly. The explosively driven shock tube was shown to produce a repeatable shock wave and vortex ring. Digital streak images show the shock wave and vortex ring propagation and expansion. The shadowgrams show that the shock wave extinguishes the propane flame by pushing it off of the fuel source. Even a weak shock wave was found to be capable of extinguishing the flame.

  8. Burnett-Cattaneo continuum theory for shock waves.

    Science.gov (United States)

    Holian, Brad Lee; Mareschal, Michel; Ravelo, Ramon

    2011-02-01

    We model strong shock-wave propagation, both in the ideal gas and in the dense Lennard-Jones fluid, using a refinement of earlier work, which accounts for the cold compression in the early stages of the shock rise by a nonlinear, Burnett-like, strain-rate dependence of the thermal conductivity, and relaxation of kinetic-temperature components on the hot, compressed side of the shock front. The relaxation of the disequilibrium among the three components of the kinetic temperature, namely, the difference between the component in the direction of a planar shock wave and those in the transverse directions, particularly in the region near the shock front, is accomplished at a much more quantitative level by a rigorous application of the Cattaneo-Maxwell relaxation equation to a reference solution, namely, the steady shock-wave solution of linear Navier-Stokes-Fourier theory, along with the nonlinear Burnett heat-flux term. Our new continuum theory is in nearly quantitative agreement with nonequilibrium molecular-dynamics simulations under strong shock-wave conditions, using relaxation parameters obtained from the reference solution.

  9. [Extracorporeal shock wave therapy in chronic prostatitis].

    Science.gov (United States)

    Kul'chavenya, E V; Shevchenko, S Yu; Brizhatyuk, E V

    2016-04-01

    Chronic prostatitis is a prevalent urologic disease, but treatment outcomes are not always satisfactory. As a rule, chronic prostatitis results in chronic pelvic pain syndrome, significantly reducing the patient's quality of life. Open pilot prospective non-comparative study was conducted to test the effectiveness of extracorporeal shock wave therapy (ESWT) using Aries (Dornier) machine in patients with chronic prostatitis (CP) of IIIb category. A total of 27 patients underwent ESWL as monotherapy, 2 times a week for a course of 6 sessions. Exposure settings: 5-6 energy level (by sensation), the frequency of 5 Hz, 2000 pulses per session; each patient received a total energy up to 12000 mJ. per procedure. Treatment results were evaluated using NIH-CPSI (National Institute of Health Chronic Prostatitis Symptom Index) upon completing the 3 week course of 6 treatments and at 1 month after ESWT. Immediately after the ESWT course positive trend was not significant: pain index decreased from 9.1 to 7.9, urinary symptom score remained almost unchanged (4.2 at baseline, 4.1 after treatment), quality of life index also showed a slight improvement, dropping from 7.2 points to 6.0. Total NIH-CPSI score decreased from 20.5 to 18.0. One month post-treatment pain significantly decreased to 3.2 points, the urinary symptom score fell to 2.7 points, the average quality of life score was 3.9 points. ESWT, performed on Aries (Dornier) machine, is highly effective as monotherapy in patients with category IIIb chronic prostatitis.

  10. Plane shock wave structure in a dilute granular gas

    Science.gov (United States)

    Reddy, M. H. Lakshminarayana; Alam, Meheboob

    2016-11-01

    We analyse the early time evolution of the Riemann problem of planar shock wave structures for a dilute granular gas by solving Navier-Stokes equations numerically. The one-dimensional reduced Navier-Stokes equations for plane shock wave problem are solved numerically using a relaxation-type numerical scheme. The results on the shock structures in granular gases are presented for different Mach numbers and restitution coefficients. Based on our analysis on early time shock dynamics we conclude that the density and temperature profiles are "asymmetric"; the density maximum and the temperature maximum occur within the shock layer; the absolute magnitudes of longitudinal stress and heat flux which are initially zero at both end states attain maxima in a very short time and thereafter decrease with time.

  11. Growth and decay of weak shock waves in magnetogasdynamics

    Science.gov (United States)

    Singh, L. P.; Singh, D. B.; Ram, S. D.

    2016-11-01

    The purpose of the present study is to investigate the problem of the propagation of weak shock waves in an inviscid, electrically conducting fluid under the influence of a magnetic field. The analysis assumes the following two cases: (1) a planar flow with a uniform transverse magnetic field and (2) cylindrically symmetric flow with a uniform axial or varying azimuthal magnetic field. A system of two coupled nonlinear transport equations, governing the strength of a shock wave and the first-order discontinuity induced behind it, are derived that admit a solution that agrees with the classical decay laws for a weak shock. An analytic expression for the determination of the shock formation distance is obtained. How the magnetic field strength, whether axial or azimuthal, influences the shock formation is also assessed.

  12. Dispersive nature of high mach number collisionless plasma shocks: Poynting flux of oblique whistler waves.

    Science.gov (United States)

    Sundkvist, David; Krasnoselskikh, V; Bale, S D; Schwartz, S J; Soucek, J; Mozer, F

    2012-01-13

    Whistler wave trains are observed in the foot region of high Mach number quasiperpendicular shocks. The waves are oblique with respect to the ambient magnetic field as well as the shock normal. The Poynting flux of the waves is directed upstream in the shock normal frame starting from the ramp of the shock. This suggests that the waves are an integral part of the shock structure with the dispersive shock as the source of the waves. These observations lead to the conclusion that the shock ramp structure of supercritical high Mach number shocks is formed as a balance of dispersion and nonlinearity.

  13. Numerical Study of Shock Wave Attenuation in Two-Dimensional Ducts Using Solid Obstacles: How to Utilize Shock Focusing Techniques to Attenuate Shock Waves

    Directory of Open Access Journals (Sweden)

    Qian Wan

    2015-04-01

    Full Text Available Research on shock wave mitigation in channels has been a topic of much attention in the shock wave community. One approach to attenuate an incident shock wave is to use obstacles of various geometries arranged in different patterns. This work is inspired by the study from Chaudhuri et al. (2013, in which cylinders, squares and triangles placed in staggered and non-staggered subsequent columns were used to attenuate a planar incident shock wave. Here, we present numerical simulations using a different obstacle pattern. Instead of using a matrix of obstacles, an arrangement of square or cylindrical obstacles placed along a logarithmic spiral curve is investigated, which is motivated by our previous work on shock focusing using logarithmic spirals. Results show that obstacles placed along a logarithmic spiral can delay both the transmitted and the reflected shock wave. For different incident shock Mach numbers, away from the logarithmic spiral design Mach number, this shape is effective to either delay the transmitted or the reflected shock wave. Results also confirm that the degree of attenuation depends on the obstacle shape, effective flow area and obstacle arrangement, much like other obstacle configurations.

  14. Attenuation of shock waves in copper and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, W.B.

    1986-06-01

    By using shock pins, data were gathered on the trajectories of shock waves in stainless steel (SS-304L) and oxygen-free-high-conductivity copper (OFHC-Cu). Shock pressures were generated in these materials by impacting the appropriate target with thin (approx.1.5 mm) flying plates. The flying plates in these experiments were accelerated to high velocities (approx.4 km/s) by high explosives. Six experiments were conducted, three using SS-304L as the target material and three experiments using OFHC-Cu as the target material. Peak shock pressures generated in the steel experiments were approximately 109, 130, and 147 GPa and in the copper experiments, the peak shock pressures were approximately 111, 132, and 143 GPa. In each experiment, an attenuation of the shock wave by a following release wave was clearly observed. An extensive effort using two characteristic codes (described in this work) to theoretically calculate the attenuation of the shock waves was made. The efficacy of several different constitutive equations to successfully model the experiments was studied by comparing the calculated shock trajectories to the experimental data. Based on such comparisons, the conclusion can be drawn that OFHC-Cu enters a melt phase at about 130 GPa on the principal Hugoniot. There was no sign of phase changes in the stainless-steel experiments. In order to match the observed attenuation of the shock waves in the SS-304L experiments, it was necessary to include strength effects in the calculations. It was found that the values for the parameters in the strength equations were dependent on the equation of state used in the modeling of the experiments. 66 refs., 194 figs., 77 tabs.

  15. Characterization of the Shock Wave Structure in Water

    Science.gov (United States)

    Teitz, Emilie Maria

    The scientific community is interested in furthering the understanding of shock wave structures in water, given its implications in a wide range of applications; from researching how shock waves penetrate unwanted body tissues to studying how humans respond to blast waves. Shock wave research on water has existed for over five decades. Previous studies have investigated the shock response of water at pressures ranging from 1 to 70 GPa using flyer plate experiments. This report differs from previously published experiments in that the water was loaded to shock pressures ranging from 0.36 to 0.70 GPa. The experiment also utilized tap water rather than distilled water as the test sample. Flyer plate experiments were conducted in the Shock Physics Laboratory at Marquette University to determine the structure of shock waves within water. A 12.7 mm bore gas gun fired a projectile made of copper, PMMA, or aluminum at a stationary target filled with tap water. Graphite break pins in a circuit determined the initial projectile velocity prior to coming into contact with the target. A Piezoelectric timing pin (PZT pin) at the front surface of the water sample determined the arrival of the leading wave and a Photon Doppler Velocimeter (PDV) measured particle velocity from the rear surface of the water sample. The experimental results were compared to simulated data from a Eulerian Hydrocode called CTH [1]. The experimental results differed from the simulated results with deviations believed to be from experimental equipment malfunctions. The main hypothesis being that the PZT pin false triggered, resulting in measured lower than expected shock velocities. The simulated results were compared to published data from various authors and was within range.

  16. Non-classical dispersive shock waves in shallow water

    Science.gov (United States)

    Sprenger, Patrick; Hoefer, Mark

    2016-11-01

    A classical model for shallow water waves with strong surface tension is the Kawahara equation, which is the Korteweg-de Vries (KdV) including a fifth order derivative term. A particular problem of interest to these types of equations is step initial data, known as the Riemann problem, which results in a shock in finite time. Unlike classical shock waves, where a discontinuity is resolved by dissipation, the dispersive regularization results in the discontinuity resolved as a dispersive shock wave (DSW). When parameter choices result in non-convex dispersion, three distinct dynamic regimes are observed that can be characterized solely by the amplitude of the initial step. For small jumps, a perturbed KdV DSW with positive polarity and orientation is generated, accompanied by small amplitude radiation from an embedded solitary wave leading edge, termed a radiating DSW. For moderate jumps, a crossover regime is observed with waves propagating forward and backward from the sharp transition region. For sufficiently large jumps, a new type of DSW is observed we term a translating DSW were a partial, non-monotonic, negative solitary wave at the trailing edge is connected to an interior nonlinear periodic wave and exhibits features common to both dissipative and dispersive shock waves.

  17. Geometry of fast magnetosonic rays, wavefronts and shock waves

    Science.gov (United States)

    Núñez, Manuel

    2016-11-01

    Fast magnetosonic waves in a two-dimensional plasma are studied in the geometrical optics approximation. The geometry of rays and wavefronts influences decisively the formation and ulterior evolution of shock waves. It is shown that the curvature of the curve where rays start and the angle between rays and wavefronts are the main parameters governing a wide variety of possible outcomes.

  18. Distribution Regularity of Muzzle Shock-Wave Inside Protective Cover

    Institute of Scientific and Technical Information of China (English)

    WU Jun; LIU Jingbo; DU Yixin

    2006-01-01

    The injury of gunners caused by muzzle shock-wave has always been a great problem when firing inside the protective cover.The distribution regularity and personnel injury from the muzzle blast-wave were investigated by both test and numerical simulation.Through the inside firing test,the changes of overpressure and noise have been measured at different measuring points in the thin-wall cover structure with different open widths and shallow covering thickness.The distribution regularity of muzzle shock-wave with different firing port widths is calculated by ANSYS/LSDYNA software.The overpressure distribution curves of muzzle shock-wave inside the structure can be obtained by comparing the test results with the numerical results.Then,the influence of open width and shallow covering thickness is proposed to give a reference to the protective design under the condition of the inside firing with the same cannon caliber.

  19. Rogue and shock waves in nonlinear dispersive media

    CERN Document Server

    Resitori, Stefania; Baronio, Fabio

    2016-01-01

    This self-contained set of lectures addresses a gap in the literature by providing a systematic link between the theoretical foundations of the subject matter and cutting-edge applications in both geophysical fluid dynamics and nonlinear optics. Rogue and shock waves are phenomena that may occur in the propagation of waves in any nonlinear dispersive medium. Accordingly, they have been observed in disparate settings – as ocean waves, in nonlinear optics, in Bose-Einstein condensates, and in plasmas. Rogue and dispersive shock waves are both characterized by the development of extremes: for the former, the wave amplitude becomes unusually large, while for the latter, gradients reach extreme values. Both aspects strongly influence the statistical properties of the wave propagation and are thus considered together here in terms of their underlying theoretical treatment. This book offers a self-contained graduate-level text intended as both an introduction and reference guide for a new generation of scientists ...

  20. A new numerical method for shock wave propagation based on geometrical shock dynamics

    Science.gov (United States)

    Schwendeman, D. W.

    1993-05-01

    In this paper, a new numerical method for calculating the motion of shock waves in two and three dimensions is presented. The numerical method is based on Whitham's theory of geometrical shock dynamics, which is an approximate theory that determines the motion of the leading shockfront explicitly. The numerical method uses a conservative finite difference discretization of the equations of geometrical shock dynamics. These equations are similar to those for steady supersonic potential flow, and thus the numerical method developed here is similar to ones developed for that context. Numerical results are presented for shock propagation in channels and for converging cylindrical and spherical shocks. The channel problem is used in part to compare this new numerical method with ones developed earlier. Converging cylindrical and spherical shocks arc calculated to analyze their stability.

  1. Shock Waves in Dense Hard Disk Fluids

    OpenAIRE

    Sirmas, Nick; Tudorache, Marion; Barahona, Javier; Radulescu, Matei I.

    2011-01-01

    Media composed of colliding hard disks (2D) or hard spheres (3D) serve as good approximations for the collective hydrodynamic description of gases, liquids and granular media. In the present study, the compressible hydrodynamics and shock dynamics are studied for a two-dimensional hard-disk medium at both the continuum and discrete particle level descriptions. For the continuum description, closed form analytical expressions for the inviscid hydrodynamic description, shock Hugoniot, isentropi...

  2. Collisionless shock waves mediated by Weibel Instability

    Science.gov (United States)

    Naseri, Neda; Ruan, Panpan; Zhang, Xi; Khudik, Vladimir; Shvets, Gennady

    2015-11-01

    Relativistic collisionless shocks are common events in astrophysical environments. They are thought to be responsible for generating ultra-high energy particles via the Fermi acceleration mechanism. It has been conjectured that the formation of collisionless shocks is mediated by the Weibel instability that takes place when two initially cold, unmagnetized plasma shells counter-propagate into each other with relativistic drift velocities. Using a PIC code, VLPL, which is modified to suppress numerical Cherenkov instabilities, we study the shock formation and evolution for asymmetric colliding shells with different densities in their own proper reference frame. Plasma instabilities in the region between the shock and the precursor are also investigated using a moving-window simulation that advances the computational domain at the shock's speed. This method helps both to save computation time and avoid severe numerical Cherenkov instabilities, and it allows us to study the shock evolution in a longer time period. Project is supported by US DOE grants DE-FG02-04ER41321 and DE-FG02-07ER54945.

  3. A suppressor to prevent direct wave-induced cavitation in shock wave therapy devices

    Science.gov (United States)

    Matula, Thomas J.; Hilmo, Paul R.; Bailey, Michael R.

    2005-07-01

    Cavitation plays a varied but important role in lithotripsy. Cavitation facilitates stone comminution, but can also form an acoustic barrier that may shield stones from subsequent shock waves. In addition, cavitation damages tissue. Spark-gap lithotripters generate cavitation with both a direct and a focused wave. The direct wave propagates as a spherically diverging wave, arriving at the focus ahead of the focused shock wave. It can be modeled with the same waveform (but lower amplitude) as the focused wave. We show with both simulations and experiments that bubbles are forced to grow in response to the direct wave, and that these bubbles can still be large when the focused shock wave arrives. A baffle or ``suppressor'' that blocks the propagation of the direct wave is shown to significantly reduce the direct wave pressure amplitude, as well as direct wave-induced bubble growth. These results are applicable to spark-gap lithotripters and extracorporeal shock wave therapy devices, where cavitation from the direct wave may interfere with treatment. A simple direct-wave suppressor might therefore be used to improve the therapeutic efficacy of these devices.

  4. Shock waves do more than just crush stones: extracorporeal shock wave therapy in plantar fasciitis.

    Science.gov (United States)

    Rajkumar, P; Schmitgen, G F

    2002-12-01

    Heel pain is a common orthopaedic problem, The cause of this clinical entity remains an enigma. The overall prognosis is good, however, and the symptoms generally settle well with time. There appears to be little evidence of the effectiveness of local steroid injections and dorsiflexion night splints. Extracorporeal shock wave therapy (ECSW) has been used in orthopaedics since the 1980s. With this, a new tool has become available for the treatment of plantar fasciitis, achillis tendinitis, shoulder pain and tendinosis of the elbow. In our pilot study we found good results with the use of ECSW therapy in resistant plantar fasciitis. Additional controlled studies are required to define the precise role of this new modality in the treatment of chronic plantar fasciitis.

  5. Treatment of nonunions of long bone fractures with shock waves

    Science.gov (United States)

    Wang, Ching-Jen

    2003-10-01

    A prospective clinical study investigated the effectiveness of shock waves in the treatment of 72 patients with 72 nonunions of long bone fractures (41 femurs, 19 tibias, 7 humeri, 1 radius, 3 ulnas and 1 metatarsal). The doses of shock waves were 6000 impulses at 28 kV for the femur and tibia, 3000 impulses at 28 kV for the humerus, 2000 impulses at 24 kV for the radius and ulna, and 1000 impulses at 20 kV for the metatarsal. The results of treatment were assessed clinically, and fracture healing was assessed with plain x-rays and tomography. The rate of bony union was 40% at 3 months, 60.9% at 6 months and 80% at 12 months followup. Shock wave treatment was most successful in hypertrophic nonunions and nonunions with a defect and was least effective in atrophic nonunions. There were no systemic complications or device-related problems. Local complications included petechiae and hematoma formation that resolved spontaneously. In the author's experience, the results of the shock wave treatment were similar to the results of surgical treatment for chronic nonunions with no surgical risks. Shock wave treatment is a safe and effective alternative method in the treatment of chronic nonunions of long bones.

  6. Effects of extracorporeal shock wave therapy on fracture nonunions.

    Science.gov (United States)

    Vulpiani, Maria C; Vetrano, Mario; Conforti, Federica; Minutolo, Lucia; Trischitta, Donatella; Furia, John P; Ferretti, Andrea

    2012-09-01

    The purpose of this study was to examine the effect of focused extracorporeal shock wave therapy (ESWT) on the treatment of nonunions. As part of a prospective study, we included 143 patients (average age, 41.4 years) with a diagnosis of nonunion (mean, 14.1 months; range, 6-84 months). High-energy shock wave treatment was applied using shock wave generator. The shock waves were applied in 3-5 sessions of 2500 to 3000 impulses each given at 0.25-0.84 mJ/mm(2), at intervals of 48-72 hours between sessions. A maximum of 3 cycles of treatment was given, at 3-month intervals. The patients were followed during a 12-month period until fracture healing or, in case of failure, until another therapy was adopted. Complete healing was observed in 80 of 143 cases (55.9%) at an average time of 7.6 months (range 2-24 months). Partial healing occurred in 41 cases (28.7%) and no healing was observed in 22 cases (15.4%). Patients with trophic nonunions had a better success rate than patients with atrophic nonunions (Pextracorporeal shock wave therapy is a safe and effective treatment for nonunion. ESWT is more effective for trophic nonunions than atrophic nonunions.

  7. Radial extracorporeal shock wave treatment harms developing chicken embryos

    Science.gov (United States)

    Kiessling, Maren C.; Milz, Stefan; Frank, Hans-Georg; Korbel, Rüdiger; Schmitz, Christoph

    2015-01-01

    Radial extracorporeal shock wave treatment (rESWT) has became one of the best investigated treatment modalities for cellulite, including the abdomen as a treatment site. Notably, pregnancy is considered a contraindication for rESWT, and concerns have been raised about possible harm to the embryo when a woman treated with rESWT for cellulite is not aware of her pregnancy. Here we tested the hypothesis that rESWT may cause serious physical harm to embryos. To this end, chicken embryos were exposed in ovo to various doses of radial shock waves on either day 3 or day 4 of development, resembling the developmental stage of four- to six-week-old human embryos. We found a dose-dependent increase in the number of embryos that died after radial shock wave exposure on either day 3 or day 4 of development. Among the embryos that survived the shock wave exposure a few showed severe congenital defects such as missing eyes. Evidently, our data cannot directly be used to draw conclusions about potential harm to the embryo of a pregnant woman treated for cellulite with rESWT. However, to avoid any risks we strongly recommend applying radial shock waves in the treatment of cellulite only if a pregnancy is ruled out. PMID:25655309

  8. Cylindrical sound wave generated by shock-vortex interaction

    Science.gov (United States)

    Ribner, H. S.

    1985-01-01

    The passage of a columnar vortex broadside through a shock is investigated. This has been suggested as a crude, but deterministic, model of the generation of 'shock noise' by the turbulence in supersonic jets. The vortex is decomposed by Fourier transform into plane sinusoidal shear waves disposed with radial symmetry. The plane sound waves produced by each shear wave/shock interaction are recombined in the Fourier integral. The waves possess an envelope that is essentially a growing cylindrical sound wave centered at the transmitted vortex. The pressure jump across the nominal radius R = ct attenuates with time as 1/(square root of R) and varies around the arc in an antisymmetric fashion resembling a quadrupole field. Very good agreement, except near the shock, is found with the antisymmetric component of reported interferometric measurements in a shock tube. Beyond the front r approximately equals R is a precursor of opposite sign, that decays like 1/R, generated by the 1/r potential flow around the vortex core. The present work is essentially an extension and update of an early approximate study at M = 1.25. It covers the range (R/core radius) = 10, 100, 1000, and 10,000 for M = 1.25 and (in part) for M = 1.29 and, for fixed (R/core radius) = 1000, the range M = 1.01 to infinity.

  9. Molecular beam brightening by shock-wave suppression

    CERN Document Server

    Segev, Yair; Akerman, Nitzan; Shagam, Yuval; Luski, Alon; Karpov, Michael; Narevicius, Julia; Narevicius, Edvardas

    2016-01-01

    Supersonic beams are a prevalent source of cold molecules utilized in the study of chemical reactions, atom interferometry, gas-surface interactions, precision spectroscopy, molecular cooling and more. The triumph of this method emanates from the high densities produced in relation to other methods, however beam density remains fundamentally limited by interference with shock waves reflected from collimating surfaces. Here we show experimentally that this shock interaction can be reduced or even eliminated by cryo-cooling the interacting surface. An increase in beam density of nearly an order of magnitude was measured at the lowest surface temperature, with no further fundamental limitation reached. Visualization of the shock waves by plasma discharge and reproduction with direct simulation Monte Carlo calculations both indicate that the suppression of the shock structure is partially caused by lowering the momentum flux of reflected particles, and significantly enhanced by the adsorption of particles to the ...

  10. Coherent optical photons from shock waves in crystals.

    Science.gov (United States)

    Reed, Evan J; Soljacić, Marin; Gee, Richard; Joannopoulos, J D

    2006-01-13

    We predict that coherent electromagnetic radiation in the 1-100 THz frequency range can be generated in crystalline materials when subject to a shock wave or soliton-like propagating excitation. To our knowledge, this phenomenon represents a fundamentally new form of coherent optical radiation source that is distinct from lasers and free-electron lasers. The radiation is generated by the synchronized motion of large numbers of atoms when a shock wave propagates through a crystal. General analytical theory and NaCl molecular dynamics simulations demonstrate coherence lengths on the order of mm (around 20 THz) and potentially greater. The emission frequencies are determined by the shock speed and the lattice constants of the crystal and can potentially be used to determine atomic-scale properties of the shocked material.

  11. TEMPERATURE MEASUREMENT OF REFLECTED SHOCK WAVE BY USING CHEMICAL INDICATOR

    Institute of Scientific and Technical Information of China (English)

    Cui Jiping; He Yuzhong; Wang Su; Wang Jing; Fan Bingcheng

    2000-01-01

    This report describes a new method for measuring the temperature of the gas behind the reflected shock wave in shock tube,corresponding to the reservoir temperature of a shock tunnel,based on the chemical reaction of small amount of CF4 premixed in the test gas.The final product C2F4 is used as the temperature indicator,which is sampled and detected by a gas chromatography in the experiment.The detected concentration of C2F4 is correlated to the temperature of the reflected shock wave with the initial pressure P1 and test time γas parameters in the temperature range 3300K<T<5600K,pressure range 5kPa<P1<12kPa andγ≈0.4ms.

  12. Structures of Strong Shock Waves in Dense Plasmas

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhong-He; HE Yong; HU Xi-Wei; LV Jian-Hong; HU Ye-Min

    2007-01-01

    @@ Structures of strong shock waves in dense plasmas are investigated via the steady-state Navier-Stokes equations and Poisson equation. The structures from fluid simulation agree with the ones from kinetic simulation. The effects of the transport coefficients on the structures are analysed. The enhancements of the electronic heat conduction and ionic viscosity both will broaden the width of the shock fronts, and decrease the electric fields in the fronts.

  13. Shock wave propagation in soda lime glass using optical shadowgraphy

    Indian Academy of Sciences (India)

    PRASAD Y B S R; BARNWAL S; NAIK P A; YADAV Y; PATIDAR R; KAMATH M P; UPADHYAY A; BAGCHI S; KUMAR A; JOSHI A S; GUPTA P D

    2016-07-01

    Propagation of shock waves in soda lime glass, which is a transparent material, has been studied using the optical shadowgraphy technique. The time-resolved shock velocity information has been obtained (1) in single shot, using the chirped pulse shadowgraphy technique, with a temporal resolution of tens of picoseconds and (2) in multiple shots, using conventional snapshot approach, with a second harmonic probe pulse. Transient shock velocities of $(5–7) \\times 10^{6}$ cm/s have been obtained. The scaling of the shock velocity with intensity in the $2 \\times 10^{13}–10^{14}$ W/cm$^2$ range has been obtained. The shock velocity is observed to scale with laser intensity as $I^{0.38}$. The present experiments also show the presence of ionization tracks, generated probably due to X-ray hotspots from small-scale filamentation instabilities. The results and various issues involved in these experiments are discussed

  14. On electromagnetic instabilities at ultra-relativistic shock waves

    CERN Document Server

    Lemoine, Martin

    2009-01-01

    (Abridged) This paper addresses the issue of magnetic field generation in a relativistic shock precursor through micro-instabilities. The level of magnetization of the upstream plasma turns out to be a crucial parameter, notably because the length scale of the shock precursor is limited by the Larmor rotation of the accelerated particles in the background magnetic field and the speed of the shock wave. We discuss in detail and calculate the growth rates of the following beam plasma instabilities seeded by the accelerated and reflected particle populations: for an unmagnetized shock, the Weibel and filamentation instabilities, as well as the Cerenkov resonant longitudinal and oblique modes; for a magnetized shock, in a generic oblique configuration, the Weibel instability and the resonant Cerenkov instabilities with Alfven, Whisler and extraordinary modes. All these instabilities are generated upstream, then they are transmitted downstream. The modes excited by Cerenkov resonant instabilities take on particula...

  15. Observation of thermoacoustic shock waves in a resonance tube.

    Science.gov (United States)

    Biwa, Tetsushi; Sobata, Kazuya; Otake, Shota; Yazaki, Taichi

    2014-09-01

    This paper reports thermally induced shock waves observed in an acoustic resonance tube. Self-sustained oscillations of a gas column were created by imposing an axial temperature gradient on the short stack of plates installed in the resonance tube filled with air at atmospheric pressure. The tube length and axial position of the stack were examined so as to make the acoustic amplitude of the gas oscillations maximum. The periodic shock wave was observed when the acoustic pressure amplitude reached 8.3 kPa at the fundamental frequency. Measurements of the acoustic intensity show that the energy absorption in the stack region with the temperature gradient tends to prevent the nonlinear excitation of harmonic oscillations, which explains why the shock waves had been unfavorable in the resonance tube thermoacoustic systems.

  16. Finite difference solutions to shocked acoustic waves

    Science.gov (United States)

    Walkington, N. J.; Eversman, W.

    1983-01-01

    The MacCormack, Lambda and split flux finite differencing schemes are used to solve a one dimensional acoustics problem. Two duct configurations were considered, a uniform duct and a converging-diverging nozzle. Asymptotic solutions for these two ducts are compared with the numerical solutions. When the acoustic amplitude and frequency are sufficiently high the acoustic signal shocks. This condition leads to a deterioration of the numerical solutions since viscous terms may be required if the shock is to be resolved. A continuous uniform duct solution is considered to demonstrate how the viscous terms modify the solution. These results are then compared with a shocked solution with and without viscous terms. Generally it is found that the most accurate solutions are those obtained using the minimum possible viscosity coefficients. All of the schemes considered give results accurate enough for acoustic power calculations with no one scheme performing significantly better than the others.

  17. Detonation Initiation by Annular Jets and Shock Waves

    Science.gov (United States)

    2007-11-02

    acquisition card and processed by a Labview program. 1. Diaphragm Selection for Shock Tube Several different diaphragms were used in the shock tube to vary...acquisition cards running in master-slave configuration and processed with a Labview program. Recording of the test section data acquisition system was...pa -1)E+ (-Y + 1) P5=1+ P2 I ½ -1+1 Pll + 2 - 1 + ( I + I)(M 2 (7) 1+7+1(2_ 1) Thus, the pressure ratio across the reflected shock wave can be found

  18. An analysis of whistler waves at interplanetary shocks

    Science.gov (United States)

    Lengyel-Frey, D.; Farrell, W. M.; Stone, R. G.; Balogh, A.; Forsyth, R.

    1994-01-01

    We present an analysis of whistler wave magnetic and electric field amplitude ratios from which we compute wave propagation angles and energies of electrons in resonance with the waves. To do this analysis, we compute the theoretical dependence of ratios of wave components on the whistler wave propagation angle Theta for various combinations of orthogonal wave components. Ratios of wave components that would be observed by a spinning spacecraft are determined, and the effects of arbitrary inclinations of the spacecraft to the ambient magnetic field and to the whistler wave vector are studied. This analysis clearly demonstrates that B/E, the ratio of magnetic to electric field amplitudes, cannot be assumed to be the wave index of refraction, contrary to assumptions of some earlier studies. Therefore previous interpretations of whistler wave observations based on this assumption must be reinvestigated. B/E ratios derived using three orthogonal wave components can be used to unambiguously determine Theta. Using spin plane observations alone, a significant uncertainty occurs in the determination of Theta. Nevertheless, for whistler waves observed downstream of several interplanetary shocks by the Ulysses plasma wave experiment we find that Theta is highly oblique. We suggest that the analysis of wave amplitude ratios used in conjunction with traditional stability analyses provide a promising tool for determining which particle distributions and resonances are likely to be dominant contributors to wave growth.

  19. Potential of shock waves to remove calculus and biofilm.

    Science.gov (United States)

    Müller, Philipp; Guggenheim, Bernhard; Attin, Thomas; Marlinghaus, Ernst; Schmidlin, Patrick R

    2011-12-01

    Effective calculus and biofilm removal is essential to treat periodontitis. Sonic and ultrasonic technologies are used in several scaler applications. This was the first feasibility study to assess the potential of a shock wave device to remove calculus and biofilms and to kill bacteria. Ten extracted teeth with visible subgingival calculus were treated with either shock waves for 1 min at an energy output of 0.4 mJ/mm(2) at 3 Hz or a magnetostrictive ultrasonic scaler at medium power setting for 1 min, which served as a control. Calculus was determined before and after treatment planimetrically using a custom-made software using a grey scale threshold. In a second experiment, multispecies biofilms were formed on saliva-preconditioned bovine enamel discs during 64.5 h. They were subsequently treated with shock waves or the ultrasonic scaler (N = 6/group) using identical settings. Biofilm detachment and bactericidal effects were then assessed. Limited efficiency of the shock wave therapy in terms of calculus removal was observed: only 5% of the calculus was removed as compared to 100% when ultrasound was used (P ≤ 0.0001). However, shock waves were able to significantly reduce adherent bacteria by three orders of magnitude (P ≤ 0.0001). The extent of biofilm removal by the ultrasonic device was statistically similar. Only limited bactericidal effects were observed using both methods. Within the limitations of this preliminary study, the shock wave device was not able to reliably remove calculus but had the potential to remove biofilms by three log steps. To increase the efficacy, technical improvements are still required. This novel noninvasive intervention, however, merits further investigation.

  20. Lower hybrid waves at the shock front: a reassessment

    Directory of Open Access Journals (Sweden)

    S. N. Walker

    2008-03-01

    Full Text Available The primary process occurring at a collisionless shock is the redistribution of the bulk upstream energy into other degrees of freedom. One part of this process results in the acceleration of electrons at the shock front. Accelerated electrons are observed at the terrestrial and other planetary shocks, comets, and their effects are observed in astrophysical phenomena such as supernova remnants and jets in the form of X-ray bremsstrahlung radiation. One of the physical models for electron acceleration at supercritical shocks is based on low-hybrid turbulence due to the presence of reflected ions in the foot region. Since lower hybrid waves propagate almost perpendicular to the magnetic field they can be simultaneously in resonance with both the unmagnetised ions (ω=Vik and magnetised electrons (ω=Vek||. In this paper, Cluster observations of the electric field are used to study the occurrence of lower hybrid waves in the front of the terrestrial bow shock. It is shown that the lower hybrid waves exist as isolated wave packets. However, the very low level of the observed lower hybrid turbulence is too small to impart significant energisation to the electron population.

  1. A Study of Uranus' Bow Shock Motions Using Langmuir Waves

    Science.gov (United States)

    Xue, S.; Cairns, I. H.; Smith, C. W.; Gurnett, D. A.

    1996-01-01

    During the Voyager 2 flyby of Uranus, strong electron plasma oscillations (Langmuir waves) were detected by the plasma wave instrument in the 1.78-kHz channel on January 23-24, 1986, prior to the inbound bow shock crossing. Langmuir waves are excited by energetic electrons streaming away from the bow shock. The goal of this work is to estimate the location and motion of Uranus' bow shock using Langmuir wave data, together with the spacecraft positions and the measured interplanetary magnetic field. The following three remote sensing analyses were performed: the basic remote sensing method, the lag time method, and the trace-back method. Because the interplanetary magnetic field was highly variable, the first analysis encountered difficulties in obtaining a realistic estimation of Uranus' bow shock motion. In the lag time method developed here, time lags due to the solar wind's finite convection speed are taken into account when calculating the shock's standoff distance. In the new trace-back method, limits on the standoff distance are obtained as a function of time by reconstructing electron paths. Most of the results produced by the latter two analyses are consistent with predictions based on the standard theoretical model and the measured solar wind plasma parameters. Differences between our calculations and the theoretical model are discussed.

  2. ShockWave science and technology reference library

    CERN Document Server

    2007-01-01

    This book is the first of several volumes on solids in the Shock Wave Science and Technology Reference Library. These volumes are primarily concerned with high-pressure shock waves in solid media, including detonation, high-velocity impact, and penetration. Of the eight chapters in this volume three chapters survey recent, exciting experimental advances in - ultra-short shock dynamics at the atomic and molecular scale (D.S. More, S.D. Mcgrane, and D.J. Funk), - Z accelerator for ICE and Shock compression (M.D. Knudson), and - failure waves in glass and ceramics (S.J. Bless and N.S. Brar). The subsequent four chapters are foundational, and cover the subjects of - equation of state (R. Menikoff), - elastic-plastic shock waves (R. Menikoff), - continuum plasticity (R. M. Brannon), and - numerical methods (D. J. Benson). The last chapter, but not the least, describes a tour de force illustration of today’s computing power in - modeling heterogeneous reactive solids at the grain scale (M.R. Baer). All chapters a...

  3. [Musculoskeletal shock wave therapy--current database of clinical research].

    Science.gov (United States)

    Rompe, J D; Buch, M; Gerdesmeyer, L; Haake, M; Loew, M; Maier, M; Heine, J

    2002-01-01

    During the past decade application of extracorporal shock waves became an established procedure for the treatment of various musculoskeletal diseases in Germany. Up to now the positive results of prospective randomised controlled trials have been published for the treatment of plantar fasciitis, lateral elbow epicondylitis (tennis elbow), and of calcifying tendinitis of the rotator cuff. Most recently, contradicting results of prospective randomised placebo-controlled trials with adequate sample size calculation have been reported. The goal of this review is to present information about the current clinical database on extracorporeal shock wave treatment (ESWT).

  4. Numerical analysis of welded joint treated by explosion shock waves

    Institute of Scientific and Technical Information of China (English)

    GUAN Jianjun; CHEN Huaining

    2007-01-01

    This paper focuses on the simulation of welding residual stresses and the action of explosion shock waves on welding residual stresses. Firstly, the distributions of welding temperature field and residual stress on a butt joint were numerically simulated with the sequentially coupled method. Secondly, the effect of explosion shock waves, produced by plastic strip-like explosive, on welding residual stress distri-bution was predicted with coupled Lagrange-ALE algorithm.It was implicated that explosion treatment could effectively reduce welding residual stresses. The simulation work lays a foundation for the further research on the rule of explosion treatment's effect on welding residual stresses and the factors that may influence it.

  5. Shock wave emission during the collapse of cavitation bubbles

    Science.gov (United States)

    Garen, W.; Hegedűs, F.; Kai, Y.; Koch, S.; Meyerer, B.; Neu, W.; Teubner, U.

    2016-07-01

    Shock wave emission induced by intense laser pulses is investigated experimentally. The present work focuses on the conditions of shock wave emission in glycerine and distilled water during the first bubble collapse. Experimental investigations are carried out in liquids as a function of temperature and viscosity. Comparison is made with the theoretical work of Poritsky (Proc 1st US Natl Congress Appl Mech 813-821, 1952) and Brennen (Cavitation and bubble dynamics, Oxford University Press 1995). To the best knowledge of the authors, this is the first experimental verification of those theories.

  6. Shock wave fractionated noble gases in the early solar system

    Science.gov (United States)

    Ustinova, G. K.

    2001-08-01

    Many processes in the active star-forming regions are accompanied by strong shock waves, in acceleration by which the nuclear-active particles form the power-law energy spectrum of high rigidity: F(> E0) ˜ Eγ , with the spectral index γ ≤ 1.5-2. It must affect the production rates of spallogenic components of the isotopes, whose excitation functions depend on the shape of the energy spectrum of radiation. Thus, the isotopic signatures formed in the conditions of the strong shock wave propagation must be different from those formed in the calm environment. The early solar system incorporated all the presumed processes of the starforming stage, so that its matter had to conserve such isotopic anomalies. In previous works [1] the shock wave effects in generation of extinct radionu-clides and light elements Li, Be and B were considered. In the report some results for their evidence in the noble gas signatures are presented. Modelling the Kr isotope generation in spallation of Rb, Sr, Y and Zr with the nuclear-active particles, the energy spectrum of which was variable in the range of γ= 1.1-6.0, shows the different pace of growth of abundances of the dif-ferent Kr isotopes with decreasing . It leads to the quite diverse behaviour of the various Kr isotope ratios: the 78,80 Kr/83 Kr ratios increase, and the 82,84,86 Kr/83 Kr ratios decrease for the smaller γ. According to such criteria, for instance, the isotopically heavier SEP-Kr in the lunar ilmenites was pro-duced with the accelerated particles of the more rigid energy spectrum (γ ˜ 2) in comparison with the SW-Kr. Another important feature of the shock wave acceleration of particles is the enrichment of their specrtum with heavier ions in proportion to A/Z. Clearly, the shock wave fractionation of the noble gases, favouring the heavier isotopes, had to be inevitable. Such a fractionation depends on timing episodes of shock wave acceleration: after the n-th act of the ion acceleration their fractionation is

  7. STUDY OF SWEPT SHOCK WAVE AND BOUNDARY LAYER INTERACTIONS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    This paper presents briefly the recent progress on study of swept shock wave/boundary layer interactions with emphasis on application of zonalanalysis and correlation analysis to them. Based on the zonal analysis an overall framework of complicated interaction flow structure including both surface flowfield and space flowfield is discussed. Based on correlation analysis the conical interactions induced by four families of shock wave generators have been discussedin detail. Some control parameter and physical mechanism of conical interaction have been revealed. Finally some aspects of the problem and the prospects for future work are suggested.

  8. Shock waves and shock tubes; Proceedings of the Fifteenth International Symposium, Berkeley, CA, July 28-August 2, 1985

    Science.gov (United States)

    Bershader, D. (Editor); Hanson, R. (Editor)

    1986-01-01

    A detailed survey is presented of shock tube experiments, theoretical developments, and applications being carried out worldwide. The discussions explore shock tube physics and the related chemical, physical and biological science and technology. Extensive attention is devoted to shock wave phenomena in dusty gases and other multiphase and heterogeneous systems, including chemically reactive mixtures. Consideration is given to techniques for measuring, visualizing and theoretically modeling flowfield, shock wave and rarefaction wave characteristics. Numerical modeling is explored in terms of the application of computational fluid dynamics techniques to describing flowfields in shock tubes. Shock interactions and propagation, in both solids, fluids, gases and mixed media are investigated, along with the behavior of shocks in condensed matter. Finally, chemical reactions that are initiated as the result of passage of a shock wave are discussed, together with methods of controlling the evolution of laminar separated flows at concave corners on advanced reentry vehicles.

  9. Magnetohydrodynamic waves within the medium separated by the plane shock wave or rotational discontinuity

    Directory of Open Access Journals (Sweden)

    A. A. Lubchich

    2005-07-01

    Full Text Available Characteristics of small amplitude plane waves within the medium separated by the plane discontinuity into two half spaces are analysed. The approximation of the ideal one-fluid magnetohydrodynamics (MHD is used. The discontinuities with the nonzero mass flux across them are mainly examined. These are fast or slow shock waves and rotational discontinuities. The dispersion equation for MHD waves within each of half space is obtained in the reference frame connected with the discontinuity surface. The solution of this equation permits one to determine the wave vectors versus the parameter cp, which is the phase velocity of surface discontinuity oscillations. This value of cp is common for all MHD waves and determined by an incident wave or by spontaneous oscillations of the discontinuity surface. The main purpose of the study is a detailed analysis of the dispersion equation solution. This analysis let us draw the following conclusions. (I For a given cp, ahead or behind a discontinuity at most, one diverging wave can transform to a surface wave damping when moving away from the discontinuity. The surface wave can be a fast one or, in rare cases, a slow, magnetoacoustic one. The entropy and Alfvén waves always remain in a usual homogeneous mode. (II For certain values of cp and parameters of the discontinuity behind the front of the fast shock wave, there can be four slow magnetoacoustic waves, satisfying the dispersion equation, and none of the fast magnetoacoustic waves. In this case, one of the four slow magnetoacoustic waves is incident on the fast shock wave from the side of a compressed medium. It is shown that its existence does not contradict the conditions of the evolutionarity of MHD shock waves. The four slow magnetoacoustic waves, satisfying the dispersion equation, can also exist from either side of a slow shock wave or rotational discontinuity. (III The

  10. Cosmic Rays Accelerated at Cosmological Shock Waves

    Indian Academy of Sciences (India)

    Renyi Ma; Dongsu Ryu; Hyesung Kang

    2011-03-01

    Based on hydrodynamic numerical simulations and diffusive shock acceleration model, we calculated the ratio of cosmic ray (CR) to thermal energy. We found that the CR fraction can be less than ∼ 0.1 in the intracluster medium, while it would be of order unity in the warm-hot intergalactic medium.

  11. Shock wave fabricated ceramic-metal nozzles

    NARCIS (Netherlands)

    Carton, E.P.; Stuivinga, M.E.C.; Keizers, H.L.J.; Verbeek, H.J.; Put, P.J. van der

    1999-01-01

    Shock compaction was used in the fabrication of high temperature ceramic-based materials. The materials' development was geared towards the fabrication of nozzles for rocket engines using solid propellants, for which the following metal-ceramic (cermet) materials were fabricated and tested: B4C-Ti (

  12. Shock wave fabricated ceramic-metal nozzles

    NARCIS (Netherlands)

    Carton, E.P.; Stuivinga, M.E.C.; Keizers, H.L.J.; Verbeek, H.J.; Put, P.J. van der

    1999-01-01

    Shock compaction was used in the fabrication of high temperature ceramic-based materials. The materials' development was geared towards the fabrication of nozzles for rocket engines using solid propellants, for which the following metal-ceramic (cermet) materials were fabricated and tested: B4C-Ti

  13. Traveling solitary wave induced by nonlocality in dispersive shock wave generation (Conference Presentation)

    Science.gov (United States)

    Louis, Hélène; Odent, Vincent; Louvergneaux, Eric

    2016-04-01

    Shock waves are well-known nonlinear waves, displaying an abrupt discontinuity. Observation can be made in a lot of physical fields, as in water wave, plasma and nonlinear optics. Shock waves can either break or relax through either catastrophic or regularization phenomena. In this work, we restrain our study to dispersive shock waves. This regularization phenomenon implies the emission of dispersive waves. We demonstrate experimentally and numerically the generation of spatial dispersive shock waves in a nonlocal focusing media. The generation of dispersive shock wave in a focusing media is more problematic than in a defocusing one. Indeed, the modulational instability has to be frustrated to observe this phenomenon. In 2010, the dispersive shock wave was demonstrated experimentally in a focusing media with a partially coherent beam [1]. Another way is to use a nonlocal media [2]. The impact of nonlocality is more important than the modulational instability frustration. Here, we use nematic liquid crystals (NLC) as Kerr-like nonlocal medium. To achieve shock formation, we use the Riemann condition as initial spatial condition (edge at the beam entrance of the NLC cell). In these experimental conditions, we generate, experimentally and numerically, shock waves that relax through the emission of dispersive waves. Associated with this phenomenon, we evidence the emergence of a localized wave that travels through the transverse beam profile. The beam steepness, which is a good indicator of the shock formation, is maximal at the shock point position. This latter follows a power law versus the injected power as in [3]. Increasing the injected power, we found multiple shock points. We have good agreements between the numerical simulations and the experimental results. [1] W. Wan, D. V Dylov, C. Barsi, and J. W. Fleischer, Opt. Lett. 35, 2819 (2010). [2] G. Assanto, T. R. Marchant, and N. F. Smyth, Phys. Rev. A - At. Mol. Opt. Phys. 78, 1 (2008). [3] N. Ghofraniha, L. S

  14. Shock tubes and waves; Proceedings of the Thirteenth International Symposium, Niagara Falls, NY, July 6-9, 1981

    Science.gov (United States)

    Treanor, C. E.; Hall, J. G.

    1982-10-01

    The present conference on shock tubes and waves considers shock tube drivers, luminous shock tubes, shock tube temperature and pressure measurement, shock front distortion in real gases, nonlinear standing waves, transonic flow shock wave turbulent boundary interactions, wall roughness effects on reflected shock bifurcation, argon thermal conductivity, pattern generation in gaseous detonations, cylindrical resonators, shock tunnel-produced high gain lasers, fluid dynamic aspects of laser-metal interaction, and the ionization of argon gas behind reflected shock waves. Also discussed are the ionization relaxation of shock-heated plasmas and gases, discharge flow/shock tube studies of singlet oxygen, rotational and vibrational relaxation, chemiluminescence thermal and shock wave decomposition of hydrogen cyanide and hydrogen azide, shock wave structure in gas-particle mixtures at low Mach numbers, binary nucleation in a Ludwieg tube, shock liquefaction experiments, pipeline explosions, the shock wave ignition of pulverized coal, and shock-initiated methane combustion.

  15. Molecular dynamics simulations of microscopic structure of ultra strong shock waves in dense helium

    Science.gov (United States)

    Liu, Hao; Kang, Wei; Zhang, Qi; Zhang, Yin; Duan, Huilin; He, X. T.

    2016-12-01

    Hydrodynamic properties and structure of strong shock waves in classical dense helium are simulated using non-equilibrium molecular dynamics methods. The shock speed in the simulation reaches 100 km/s and the Mach number is over 250, which are close to the parameters of shock waves in the implosion process of inertial confinement fusion. The simulations show that the high-Mach-number shock waves in dense media have notable differences from weak shock waves or those in dilute gases. These results will provide useful information on the implosion process, especially the structure of strong shock wave front, which remains an open question in hydrodynamic simulations.

  16. A search for low-energy neutrinos correlated with gravitational wave events GW150914, GW151226 and GW170104 with the Borexino detector

    OpenAIRE

    Agostini, M.; Altenmuller, K.; Appel, S; Atroshchenko, V.; Bagdasarian, Z.; Basilico, D.; Bellini, G; Benziger, J.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Caprioli, S

    2017-01-01

    We present the results of a low-energy neutrino search using the Borexino detector in coincidence with the gravitational wave (GW) events GW150914, GW151226 and GW170104. We searched for correlated neutrino events with energies greater than 250 keV within a time window of $\\pm500$ s centered around the GW detection time. A total of five candidates were found for all three GW150914, GW151226 and GW170104. This is consistent with the number of expected solar neutrino and background events. As a...

  17. Response of ocean bottom dwellers exposed to underwater shock waves

    Science.gov (United States)

    Hosseini, S. H. R.; Kaiho, Kunio; Takayama, Kazuyoshi

    2016-01-01

    The paper reports results of experiments to estimate the mortality of ocean bottom dwellers, ostracoda, against underwater shock wave exposures. This study is motivated to verify the possible survival of ocean bottom dwellers, foraminifera, from the devastating underwater shock waves induced mass extinction of marine creatures which took place at giant asteroid impact events. Ocean bottom dwellers under study were ostracoda, the replacement of foraminifera, we readily sampled from ocean bottoms. An analogue experiment was performed on a laboratory scale to estimate the domain and boundary of over-pressures at which marine creatures' mortality occurs. Ostracods were exposed to underwater shock waves generated by the explosion of 100mg PETN pellets in a chamber at shock over-pressures ranging up to 44MPa. Pressure histories were measured simultaneously on 113 samples. We found that bottom dwellers were distinctively killed against overpressures of 12MPa and this value is much higher than the usual shock over-pressure threshold value for marine-creatures having lungs and balloons.

  18. Bubbles with shock waves and ultrasound: a review.

    Science.gov (United States)

    Ohl, Siew-Wan; Klaseboer, Evert; Khoo, Boo Cheong

    2015-10-06

    The study of the interaction of bubbles with shock waves and ultrasound is sometimes termed 'acoustic cavitation'. It is of importance in many biomedical applications where sound waves are applied. The use of shock waves and ultrasound in medical treatments is appealing because of their non-invasiveness. In this review, we present a variety of acoustics-bubble interactions, with a focus on shock wave-bubble interaction and bubble cloud phenomena. The dynamics of a single spherically oscillating bubble is rather well understood. However, when there is a nearby surface, the bubble often collapses non-spherically with a high-speed jet. The direction of the jet depends on the 'resistance' of the boundary: the bubble jets towards a rigid boundary, splits up near an elastic boundary, and jets away from a free surface. The presence of a shock wave complicates the bubble dynamics further. We shall discuss both experimental studies using high-speed photography and numerical simulations involving shock wave-bubble interaction. In biomedical applications, instead of a single bubble, often clouds of bubbles appear (consisting of many individual bubbles). The dynamics of such a bubble cloud is even more complex. We shall show some of the phenomena observed in a high-intensity focused ultrasound (HIFU) field. The nonlinear nature of the sound field and the complex inter-bubble interaction in a cloud present challenges to a comprehensive understanding of the physics of the bubble cloud in HIFU. We conclude the article with some comments on the challenges ahead.

  19. Lithotripter shock wave interaction with a bubble near various biomaterials

    Science.gov (United States)

    Ohl, S. W.; Klaseboer, E.; Szeri, A. J.; Khoo, B. C.

    2016-10-01

    Following previous work on the dynamics of an oscillating bubble near a bio-material (Ohl et al 2009 Phys. Med. Biol. 54 6313-36) and the interaction of a bubble with a shockwave (Klaseboer et al 2007 J. Fluid Mech. 593 33-56), the present work concerns the interaction of a gas bubble with a traveling shock wave (such as from a lithotripter) in the vicinity of bio-materials such as fat, skin, muscle, cornea, cartilage, and bone. The bubble is situated in water (to represent a water-like biofluid). The bubble collapses are not spherically symmetric, but tend to feature a high speed jet. A few simulations are performed and compared with available experimental observations from Sankin and Zhong (2006 Phys. Rev. E 74 046304). The collapses of cavitation bubbles (created by laser in the experiment) near an elastic membrane when hit by a lithotripter shock wave are correctly captured by the simulation. This is followed by a more systematic study of the effects involved concerning shockwave bubble biomaterial interactions. If a subsequent rarefaction wave hits the collapsed bubble, it will re-expand to a very large size straining the bio-materials nearby before collapsing once again. It is noted that, for hard bio-material like bone, reflection of the shock wave at the bone—water interface can affect the bubble dynamics. Also the initial size of the bubble has a significant effect. Large bubbles (˜1 mm) will split into smaller bubbles, while small bubbles collapse with a high speed jet in the travel direction of the shock wave. The numerical model offers a computationally efficient way of understanding the complex phenomena involving the interplay of a bubble, a shock wave, and a nearby bio-material.

  20. Visualizing a Dusty Plasma Shock Wave via Interacting Multiple-Model Mode Probabilities

    OpenAIRE

    Oxtoby, Neil P.; Ralph, Jason F.; Durniak, Céline; Samsonov, Dmitry

    2011-01-01

    Particles in a dusty plasma crystal disturbed by a shock wave are tracked using a three-mode interacting multiple model approach. Color-coded mode probabilities are used to visualize the shock wave propagation through the crystal.

  1. Suppression of spiral waves using intermittent local electric shock

    Institute of Scientific and Technical Information of China (English)

    Ma Jun; Ying He-Ping; Li Yan-Long

    2007-01-01

    In this paper, an intermittent local electric shock scheme is proposed to suppress stable spiral waves in the Barkley model by a weak electric shock (about 0.4 to 0.7) imposed on a random selected n × n grids (n = 1-5, compared with the original 256×256 lattice) and monitored synchronically the evolutions of the activator on the grids as the sampled signal of the activator steps out a given threshold (i.e., the electric shock works on the n × n grids if the activator u (≤) 0.4 or u (≥) 0.8). The numerical simulations show that a breakup of spiral is observed in the media state evolution to finally obtain homogeneous states if the electric shock with appropriate intensity is imposed.

  2. Maximum intensity of rarefaction shock waves for dense gases

    NARCIS (Netherlands)

    Guardone, A.; Zamfirescu, C.; Colonna, P.

    2009-01-01

    Modern thermodynamic models indicate that fluids consisting of complex molecules may display non-classical gasdynamic phenomena such as rarefaction shock waves (RSWs) in the vapour phase. Since the thermodynamic region in which non-classical phenomena are physically admissible is finite in terms of

  3. Whistler waves associated with the Uranian bow shock - Outbound observations

    Science.gov (United States)

    Smith, Charles W.; Wong, Hung K.; Goldstein, Melvyn L.

    1991-01-01

    High-resolution magnetic field measurements from the first outbound crossing of the Uranian bowshock by the Voyager 2 spacecraft between January 27 and 30, 1986, are examined. Evidence is found of enhanced whistler wave activity in the vicinity of three shock crossings but little or no evidence of such activity elsewhere. Two wave events display two separate and simultaneous wave enhancements each. From an investigation of these events using high-resolution field data, it is concluded that they are analogous to those whistler waves upstream of the earth's bow shock that are driven by beams of electrons. An instability analysis is presented to show that a single electron beam with reasonable parameters can penetrate both of the upstream and downstream of a shock crossing. This event displays only one relatively broad spectral enhancement in the same frequency regime and is left-hand polarized in the spacecraft frame. It is argued that this event is the result of a gyrating proton distribution associated with the oblique shock.

  4. Characterization and modification of cavitation pattern in shock wave lithotripsy

    NARCIS (Netherlands)

    Arora, Manish; Ohl, Claus-Dieter; Liebler, Marko

    2004-01-01

    The temporal and spatial dynamics of cavitation bubble cloud growth and collapse in extracorporeal shock wave lithotripsy (ESWL) is studied experimentally. The first objective is obtaining reproducible cloud patterns experimentally and comparing them with FDTD-calculations. Second, we describe a met

  5. Acoustic waves in shock tunnels and expansion tubes

    Science.gov (United States)

    Paull, A.; Stalker, R. J.

    1992-01-01

    It is shown that disturbances in shock and expansion tubes can be modelled as lateral acoustic waves. The ratio of sound speed across the driver-test gas interface is shown to govern the quantity of noise in the test gas. Frequency 'focusing' which is fundamental to centered unsteady expansions is discussed and displayed in centerline pitot pressure measurements.

  6. Unfocused extracorporeal shock waves induce anabolic effects in osteoporotic rats

    NARCIS (Netherlands)

    van der Jagt, Olav P.; Waarsing, Jan H.; Kops, Nicole; Schaden, Wolfgang; Jahr, Holger; Verhaar, Jan A. N.; Weinans, Harrie

    2013-01-01

    Unfocused extracorporeal shock waves (UESW) have been shown to have an anabolic effect on bone mass. Therefore we investigated the effects of UESW on bone in osteoporotic rats with and without anti-resorptive treatment. Twenty-week-old rats were ovariectomized (n=27). One group was treated with sali

  7. Stenting and extracorporeal shock wave lithotripsy in chronic pancreatitis

    DEFF Research Database (Denmark)

    Holm, M; Matzen, Peter

    2003-01-01

    BACKGROUND: Early observational studies of endoscopic treatment and extracorporeal shock wave lithotripsy (ESWL) reported considerable or complete relief of pain in 50%-80% of patients with chronic pancreatitis. There is no consensus on the measurement of pain, making comparison of observational...

  8. The gravitational shock wave of a massless particle

    NARCIS (Netherlands)

    Hooft, G. 't; Dray, T

    1985-01-01

    The (spherical) gravitational shock wave due to a massless particle moving at the speed of light along the horizon of the Schwarzchild black hole is obtained. Special cases of our procedure yield previous results by Aichelburg and Sexl[1] for a photon in Minkowski vpace and by Penrose [2] for source

  9. Effects of Surf Zone Sediment Properties on Shock Wave Behavior

    Science.gov (United States)

    2016-06-07

    to be a first order factor. In addition, modeling predictions require the compressibility of the sediments at high and low pressures . The objective...sands in a test tank and initiate shock waves with a high energy laser system. The results will be used to validate numercal model predictions of

  10. Admissibility region for rarefaction shock waves in dense gases

    NARCIS (Netherlands)

    Zamfirescu, C.; Guardone, A.; Colonna, P.

    2008-01-01

    In the vapour phase and close to the liquid–vapour saturation curve, fluids made of complex molecules are expected to exhibit a thermodynamic region in which the fundamental derivative of gasdynamic Γ is negative. In this region, non-classical gasdynamic phenomena such as rarefaction shock waves are

  11. Success of electromagnetic shock wave lithotripter as monotherapy ...

    African Journals Online (AJOL)

    K.S. Meitei

    The success rate of ESWL for both non-staghorn and staghorn calculi with size above 2 cm is low, so other treatment ..... Conflict of interest. None declared. ... Bazeed M. Prediction of success rate after extracorporeal shock-wave lithotripsy of ...

  12. THE FORMATION OF SHOCK WAVES OF THE EQUATIONS OF MAGNETOHYDRODYNAMICS

    Institute of Scientific and Technical Information of China (English)

    董黎明; 史一蓬

    2001-01-01

    The property of fluid field of one- dimensional magnetohydrodynamics (MHD)transverse flow after the appearance of singularity is discussed. By the method of iteration,the strong discontinuity (shock wave) and entropy solution are constructed and the estimations on the singularity of the solution near the point of blow- up are obtained.

  13. The effects of extracorporeal shock wave therapy on frozen shoulder patients’ pain and functions

    OpenAIRE

    2015-01-01

    [Purpose] The present study was conducted to examine the effects of extracorporeal shock wave therapy on frozen shoulder patients’ pain and functions. [Subjects] In the present study, 30 frozen shoulder patients were divided into two groups: an extracorporeal shock wave therapy group of 15 patients and a conservative physical therapy group of 15 patients. [Methods] Two times per week for six weeks, the extracorporeal shock wave therapy group underwent extracorporeal shock wave therapy, and th...

  14. Regularized Moment Equations and Shock Waves for Rarefied Granular Gas

    Science.gov (United States)

    Reddy, Lakshminarayana; Alam, Meheboob

    2016-11-01

    It is well-known that the shock structures predicted by extended hydrodynamic models are more accurate than the standard Navier-Stokes model in the rarefied regime, but they fail to predict continuous shock structures when the Mach number exceeds a critical value. Regularization or parabolization is one method to obtain smooth shock profiles at all Mach numbers. Following a Chapman-Enskog-like method, we have derived the "regularized" version 10-moment equations ("R10" moment equations) for inelastic hard-spheres. In order to show the advantage of R10 moment equations over standard 10-moment equations, the R10 moment equations have been employed to solve the Riemann problem of plane shock waves for both molecular and granular gases. The numerical results are compared between the 10-moment and R10-moment models and it is found that the 10-moment model fails to produce continuous shock structures beyond an upstream Mach number of 1 . 34 , while the R10-moment model predicts smooth shock profiles beyond the upstream Mach number of 1 . 34 . The density and granular temperature profiles are found to be asymmetric, with their maxima occurring within the shock-layer.

  15. Grain destruction in a supernova remnant shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, John C.; Gaetz, Terrance J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ghavamian, Parviz [Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252 (United States); Williams, Brian J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Blair, William P. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Borkowski, Kazimierz J. [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States); Sankrit, Ravi, E-mail: jraymond@cfa.harvard.edu [SOFIA Science Center, NASA Ames Research Center, M/S 232-12, Moffett Field, CA 94035 (United States)

    2013-12-01

    Dust grains are sputtered away in the hot gas behind shock fronts in supernova remnants (SNRs), gradually enriching the gas phase with refractory elements. We have measured emission in C IV λ1550 from C atoms sputtered from dust in the gas behind a non-radiative shock wave in the northern Cygnus Loop. Overall, the intensity observed behind the shock agrees approximately with predictions from model calculations that match the Spitzer 24 μm and the X-ray intensity profiles. Thus, these observations confirm the overall picture of dust destruction in SNR shocks and the sputtering rates used in models. However, there is a discrepancy in that the C IV intensity 10'' behind the shock is too high compared with the intensities at the shock and 25'' behind it. Variations in the density, hydrogen neutral fraction, and the dust properties over parsec scales in the pre-shock medium limit our ability to test dust destruction models in detail.

  16. Comparison of geometrical shock dynamics and kinematic models for shock-wave propagation

    Science.gov (United States)

    Ridoux, J.; Lardjane, N.; Monasse, L.; Coulouvrat, F.

    2017-09-01

    Geometrical shock dynamics (GSD) is a simplified model for nonlinear shock-wave propagation, based on the decomposition of the shock front into elementary ray tubes. Assuming small changes in the ray tube area, and neglecting the effect of the post-shock flow, a simple relation linking the local curvature and velocity of the front, known as the A{-}M rule, is obtained. More recently, a new simplified model, referred to as the kinematic model, was proposed. This model is obtained by combining the three-dimensional Euler equations and the Rankine-Hugoniot relations at the front, which leads to an equation for the normal variation of the shock Mach number at the wave front. In the same way as GSD, the kinematic model is closed by neglecting the post-shock flow effects. Although each model's approach is different, we prove their structural equivalence: the kinematic model can be rewritten under the form of GSD with a specific A{-}M relation. Both models are then compared through a wide variety of examples including experimental data or Eulerian simulation results when available. Attention is drawn to the simple cases of compression ramps and diffraction over convex corners. The analysis is completed by the more complex cases of the diffraction over a cylinder, a sphere, a mound, and a trough.

  17. Parallel implementation of geometrical shock dynamics for two dimensional converging shock waves

    Science.gov (United States)

    Qiu, Shi; Liu, Kuang; Eliasson, Veronica

    2016-10-01

    Geometrical shock dynamics (GSD) theory is an appealing method to predict the shock motion in the sense that it is more computationally efficient than solving the traditional Euler equations, especially for converging shock waves. However, to solve and optimize large scale configurations, the main bottleneck is the computational cost. Among the existing numerical GSD schemes, there is only one that has been implemented on parallel computers, with the purpose to analyze detonation waves. To extend the computational advantage of the GSD theory to more general applications such as converging shock waves, a numerical implementation using a spatial decomposition method has been coupled with a front tracking approach on parallel computers. In addition, an efficient tridiagonal system solver for massively parallel computers has been applied to resolve the most expensive function in this implementation, resulting in an efficiency of 0.93 while using 32 HPCC cores. Moreover, symmetric boundary conditions have been developed to further reduce the computational cost, achieving a speedup of 19.26 for a 12-sided polygonal converging shock.

  18. Comparative Study between Slow Shock Wave Lithotripsy and Fast Shock Wave Lithotripsy in the Management of Renal Stone

    Directory of Open Access Journals (Sweden)

    AKM Zamanul Islam Bhuiyan

    2013-01-01

    Full Text Available Background: Renal calculi are frequent causes of ureteric colic. Extracorporeal shock wave lithotripsy is the most common treatment of these stones. It uses focused sound waves to break up stones externally. Objective: To compare the efficiency of slow and fast delivery rate of shock waves on stone fragmentation and treatment outcome in patients with renal calculi. Materials and Methods: This prospective study was done in the department of Urology, National Institute of Kidney diseases and Urology, Sher-e-Bangla Nagar, Dhaka from July 2006 to June 2007. Total 90 patients were treated using the Storz Medical Modulith ® SLX lithotripter. Patients were divided into Group A, Group B and Group C – each group having 30 subjects. Group A was selected for extracorporeal shockwave lithotripsy (ESWL by 60 shock waves per minute, Group B by 90 shock waves per minute and Group C by 120 shock waves per minute. Results: Complete clearance of stone was observed in 24 patients in Group A and 13 patients in both Group B and Group C in first session. In Group A only 3 patients needed second session but in Group B and Group C, 12 and 8 patients needed second session. In Group A only one patient needed third session but third session was required for 3 patients in Group B and 5 patients in Group C for complete clearance of stone. In Group A, subsequent sessions were performed under spinal anesthesia and in Group B under sedation and analgesia (p>0.001. Mean number of sessions for full clearance of stones in group A was 1.37 ± 0.85, in Group B was 1.8 ± 0.887 and in Group C was 2.0 ± 1.083. Significant difference was observed in term of sessions among groups (p>0.05. In first follow-up, complete clearance of stones was seen in 24 patients in Group A and 13 in both Group B and Group C. In second follow-up, 3 patients in Group A, 12 in Group B and 8 in Group C showed complete clearance of stones. It was observed that rate of stone clearance was higher in Group A

  19. Evolution of perturbed accelerating relativistic shock waves

    CERN Document Server

    Palma, G; Vietri, M; Del Zanna, L

    2008-01-01

    We study the evolution of an accelerating hyperrelativistic shock under the presence of upstream inhomogeneities wrinkling the discontinuity surface. The investigation is conducted by means of numerical simulations using the PLUTO code for astrophysical fluid dynamics. The reliability and robustness of the code are demonstrated against well known results coming from the linear perturbation theory. We then follow the nonlinear evolution of two classes of perturbing upstream atmospheres and conclude that no lasting wrinkle can be preserved indefinitely by the flow. Finally we derive analytically a description of the geometrical effects of a turbulent upstream ambient on the discontinuity surface.

  20. Incoherent shock waves in long-range optical turbulence

    Science.gov (United States)

    Xu, G.; Garnier, J.; Faccio, D.; Trillo, S.; Picozzi, A.

    2016-10-01

    Considering the nonlinear Schrödinger (NLS) equation as a representative model, we report a unified presentation of different forms of incoherent shock waves that emerge in the long-range interaction regime of a turbulent optical wave system. These incoherent singularities can develop either in the temporal domain through a highly noninstantaneous nonlinear response, or in the spatial domain through a highly nonlocal nonlinearity. In the temporal domain, genuine dispersive shock waves (DSW) develop in the spectral dynamics of the random waves, despite the fact that the causality condition inherent to the response function breaks the Hamiltonian structure of the NLS equation. Such spectral incoherent DSWs are described in detail by a family of singular integro-differential kinetic equations, e.g. Benjamin-Ono equation, which are derived from a nonequilibrium kinetic formulation based on the weak Langmuir turbulence equation. In the spatial domain, the system is shown to exhibit a large scale global collective behavior, so that it is the fluctuating field as a whole that develops a singularity, which is inherently an incoherent object made of random waves. Despite the Hamiltonian structure of the NLS equation, the regularization of such a collective incoherent shock does not require the formation of a DSW - the regularization is shown to occur by means of a different process of coherence degradation at the shock point. We show that the collective incoherent shock is responsible for an original mechanism of spontaneous nucleation of a phase-space hole in the spectrogram dynamics. The robustness of such a phase-space hole is interpreted in the light of incoherent dark soliton states, whose different exact solutions are derived in the framework of the long-range Vlasov formalism.

  1. Relating molecular structure and low-energy fusion through time-dependent wave-packet dynamics: the 12C+12C collision

    Directory of Open Access Journals (Sweden)

    Diaz-Torres Alexis

    2015-01-01

    Full Text Available Recent progress in a quantitative study of the 12C+12C sub-Coulomb fusion is reported. It is carried out using full-dimensional, time-dependent wave-packet dynamics, a quantum reaction model that has not been much exploited in nuclear physics, unlike in chemical physics. The low-energy collision is described in the rotating center-of-mass frame within a nuclear molecular picture. A collective Hamiltonian drives the time propagation of the wave-packet through the collective potential-energy landscape that is calculated with a realistic two-center shell model. Among other preliminary results, the theoretical sub-Coulomb fusion resonances for 12C+12C seem to correspond well with observations. The method appears to be useful for expanding the cross-section predictions towards stellar energies.

  2. Molecular Cloud Formation Behind Shock Waves

    CERN Document Server

    Bergin, E A; Raymond, J C; Ballesteros-Paredes, J

    2004-01-01

    We examine the formation of molecular gas behind shocks in atomic gas using a chemical/dynamical model, particular emphasis is given to constraints the chemistry places on the dynamical evolution. The most important result of this study is to stress the importance of shielding the molecular gas from the destructive effects of UV radiation. For shock ram pressures comparable to or exceeding typical local ISM pressures, self-shielding controls the formation time of H2 but CO formation requires shielding of the interstellar radiation field by dust grains. We find that the molecular hydrogen fractional abundance can become significant well before CO forms. The timescale for (CO) molecular cloud formation is not set by H2 formation, but rather by the timescale for accumulating a sufficient column density or extinction, A_V > 0.7. The local ratio of atomic to molecular gas (4:1), coupled with short estimates for cloud lifetimes (3-5 Myr), suggests that the timescales for accumulating molecular clouds from atomic ma...

  3. Plasmonic shock waves and solitons in a nanoring

    Science.gov (United States)

    Koshelev, K. L.; Kachorovskii, V. Yu.; Titov, M.; Shur, M. S.

    2017-01-01

    We apply the hydrodynamic theory of electron liquid to demonstrate that a circularly polarized radiation induces the diamagnetic, helicity-sensitive dc current in a ballistic nanoring. This current is dramatically enhanced in the vicinity of plasmonic resonances. The resulting magnetic moment of the nanoring represents a giant increase of the inverse Faraday effect. With increasing radiation intensity, linear plasmonic excitations evolve into the strongly nonlinear plasma shock waves. These excitations produce a series of the well-resolved peaks at the THz frequencies. We demonstrate that the plasmonic wave dispersion transforms the shock waves into solitons. The predicted effects should enable multiple applications in a wide frequency range (from the microwave to terahertz band) using optically controlled ultralow-loss electric, photonic, and magnetic devices.

  4. Linear problem of the shock wave disturbance in a non-classical case

    Science.gov (United States)

    Semenko, Evgeny V.

    2017-06-01

    A linear problem of the shock wave disturbance for a special (non-classical) case, where both pre-shock and post-shock flows are subsonic, is considered. The phase transition for the van der Waals gas is an example of this problem. Isentropic solutions are constructed. In addition, the stability of the problem is investigated and the known result is approved: the only neutral stability case occurs here. A strictly algebraic representation of the solution in the plane of the Fourier transform is obtained. This representation allows the solution to be studied both analytically and numerically. In this way, any solution can be decomposed into a sum of acoustic and vorticity waves and into a sum of initial (generated by initial perturbations), transmitted (through the shock) and reflected (from the shock) waves. Thus, the wave incidence/refraction/reflection is investigated. A principal difference of the refraction/reflection from the classical case is found, namely, the waves generated by initial pre-shock perturbations not only pass through the shock (i.e., generate post-shock transmitted waves) but also are reflected from it (i.e., generate pre-shock reflected waves). In turn, the waves generated by the initial post-shock perturbation are not only reflected from the shock (generate post-shock reflected waves) but also pass through it (generate pre-shock transmitted waves).

  5. Dynamic and resuspension by waves and sedimentation pattern definition in low energy environments: guaíba lake (Brazil

    Directory of Open Access Journals (Sweden)

    João Luiz Nicolodi

    2013-03-01

    Full Text Available Little research has been undertaken into sediment dynamics in lakes, and most of it only analyses particular aspects such as the texture of the sediments. In this study, the characteristics of the wave field in Guaíba Lake are investigated. The parameters significant wave height (Hs, period (T and direction of wave propagation are examined together with their relation to the resuspension of sediments at the bottom. For this purpose, the mathematical model SWAN (Simulating Waves Nearshore has been validated and employed. The results pointed out that the highest waves modeled reached 0.55 m at a few points in the lake, particularly when winds were blowing from the S and SE quadrants with an intensity over 7 m.s-1. Generally speaking, waves follow wind intensity and direction patterns, and reach maximum height in about 1 to 2 hours after wind speed peaks. Whenever winds were stronger, waves took some 2 hours to reach 0.10 m. However, with weak to moderate winds, the waves took around 3 hours to achieve this value in significant wave height. In addition to speed and direction, wind regularity proved relevant in generating and propagating waves on Lake Guaíba. In conclusion the lake's sediment environments were mapped and classified as follows: 1 Depositional Environments (51% of the lake; 2 Transitional Environments (41%; and 3 Erosional or Non-Depositional Environments (8%. As a contribution to the region's environmental management, elements have been created relating to the concentration of suspended particulate matter.Pesquisas referentes à dinâmica sedimentar em lagos são escassas e a maioria trata da distribuição e textura dos sedimentos, sendo raras aquelas que fazem menção ao padrão de ondas e suas relações com a ressuspensão destes sedimentos e suas consequências. Este trabalho analisa as características das ondas incidentes no Lago Guaíba (Brasil por meio da utilização do SWAN (Simulating Waves Nearshore e suas rela

  6. Simulations of Shock Wave Interaction with a Particle Cloud

    Science.gov (United States)

    Koneru, Rahul; Rollin, Bertrand; Ouellet, Frederick; Annamalai, Subramanian; Balachandar, S.'Bala'

    2016-11-01

    Simulations of a shock wave interacting with a cloud of particles are performed in an attempt to understand similar phenomena observed in dispersal of solid particles under such extreme environment as an explosion. We conduct numerical experiments in which a particle curtain fills only 87% of the shock tube from bottom to top. As such, the particle curtain upon interaction with the shock wave is expected to experience Kelvin-Helmholtz (KH) and Richtmyer-Meshkov (RM) instabilities. In this study, the initial volume fraction profile matches with that of Sandia Multiphase Shock Tube experiments, and the shock Mach number is limited to M =1.66. In these simulations we use a Eulerian-Lagrangian approach along with state-of-the-art point-particle force and heat transfer models. Measurements of particle dispersion are made at different initial volume fractions of the particle cloud. A detailed analysis of the evolution of the particle curtain with respect to the initial conditions is presented. This work was supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science Academic Alliance Program, Contract No. DE-NA0002378.

  7. Study of a tissue protecting system for clinical applications of underwater shock wave

    Science.gov (United States)

    Hosseini, S. H. R.; Takayama, Kazuyoshi

    2005-04-01

    Applications of underwater shock waves have been extended to various clinical therapies during the past two decades. Besides the successful contribution of extracorporeal shock waves, tissue damage especially to the vasculature has been reported. These side effects are believed to be due to the shock wave-tissue interaction and cavitation. In the present research in order to minimize shock wave induced damage a shock wave attenuating system was designed and studied. The attenuating system consisted of thin gas packed layers immersed in water, which could attenuate more than 90% of shock waves overpressure. Silver azide micro-pellets (10 mg) were ignited by irradiation of a pulsed Nd:YAG laser to generate shock waves. Pressure histories were measured with fiber optic probe and PVDF needle hydrophones. The strength of incident shock waves was changed by adjusting the distance between the pellets and the layers. The whole sequences of the shock wave attenuation due to the interaction of shock waves with the dissipating layers were quantitatively visualized by double exposure holographic interferometry and time resolved high speed photography. The attenuated shock had overpressure less than threshold damage of brain tissue evaluated from histological examination of the rat brain treated by shock waves.

  8. Experimental research on dust lifting by propagating shock wave

    Science.gov (United States)

    Żydak, P.; Oleszczak, P.; Klemens, R.

    2017-03-01

    The aim of the presented work was to study the dust lifting process from a layer of dust behind a propagating shock wave. The experiments were conducted with the use of a shock tube and a specially constructed, five-channel laser optical device enabling measurements at five positions located in one vertical plane along the height of the tube. The system enabled measurements of the delay in lifting up of the dust from the layer, and the vertical velocity of the dust cloud was calculated from the dust concentration measurements. The research was carried out for various initial conditions and for three fractions of black coal dust. In the presented tests, three shock wave velocities: 450, 490 and 518 m/s and three dust layer thicknesses, equal to 1.0, 1.5 and 2.0 mm, were taken into consideration. On the grounds of the obtained experimental results, it was assumed that the vertical component of the lifted dust velocity is a function of the dust particle diameter, the velocity of the air flow in the channel, the layer thickness and the dust bulk density. It appeared, however, that lifting up of the dust from the thick layers, thicker than 1 mm, is a more complex process than that from thin layers and still requires further research. A possible explanation is that the shock wave action upon the thick layer results in its aggregation in the first stage of the dispersing process, which suppresses the dust lifting process.

  9. Simulation and Experimental Validation of Hypersonic Shock Wave Interaction

    Directory of Open Access Journals (Sweden)

    Li Jing

    2013-12-01

    Full Text Available The present paper examines the relevance of grid and simulation accuracy of hypersonic CFD in terms of hypersonic sharp double-cone flow. The flow grid and normal grid each adopted 250×100, 500×100, 1000×100, 500×200, 1000×200, 1000×400 and so on grids. When the normal grid was 100, the wall pressure and heat flux distribution obtained from flow grid 500 and 1000 were consistent, indicating that the solution of flow grid convergence was obtained. However, some difference was observed when the separation zone was compared with the experimental data. In increasing the normal grid number and adopting grid 500×200, the position of the separation point, wall pressure and heat flux peak was shown to be consistent with the experiment. When the grid was further encrypted, the calculation using grid 1000×200 and 1000×400 was equal to that using grid 500×200. The simulation of hypersonic sharp double-cone flow also showed that when the separation zone of the simulation was less than the experimental measurement, the wall pressure and heat flux peak moved forward. This is because the backwardness of the intersection of the separation shock and the first shock resulted in the forwardness of the intersection of the first shock and the second shock after interference, making the work region of the induction shock and boundary layer move forward. The key challenge in achieving the correct simulation of the hypersonic sharp double-cone flow is explained as follows: the algorithm can not only capture shock wave strength correctly and give the adverse pressure gradient formed by the interfering shock wave near the wall accurately. It can also prevent the numerical dissipation of the algorithm from affecting the simulation accuracy of the viscous boundary layer to ensure the correct prediction of the size of the separation zone.

  10. Multiple scales of shock waves in dissipative laminate materials

    Science.gov (United States)

    Franco Navarro, Pedro; Benson, David J.; Nesterenko, Vitali F.

    2016-09-01

    The shock waves generated by a plate impact are numerically investigated in Al-W laminates with different mesostructures. The main characteristic time scales (and the corresponding spatial scales) related to the formation of the stationary shock are identified: the duration (width) of the leading front, the time (distance) from the impact required to establish a stationary profile, and the shock front width, identified as a time span (distance) from the initial state to the final quasiequilibrium state. It is demonstrated that the width of the leading front and the maximum strain rates are determined by the dispersive and the nonlinear parameters of the laminate and not by the dissipation, as is the case for uniform solids. The characteristic spatial scale of the leading front is related to the spatial scale observed on solitarylike waves, which are satisfactorily described by the Korteweg-de Vries (KdV) approximation, as well as the speed of the wave and the ratio of maximum to final strain. The dissipation affects the width of the transition distance (shock front width) where multiple loading-unloading cycles bring the laminate into the final quasiequilibrium state. This spatial scale is of the same order of magnitude as the distance to form stationary shock wave. The period of fast decaying oscillations is well described by the KdV approach and scales linearly with the cell size. The rate of the decay of the oscillations in the numerical calculations does not scale with the square of the cell size as expected from the dissipative KdV approach that assumes a constant viscosity. This is due to the different mechanisms of dissipation in high-amplitude compression pulses.

  11. Resistant tennis elbow: shock-wave therapy versus percutaneous tenotomy

    OpenAIRE

    2007-01-01

    Fifty-six patients who suffered from chronic persistent tennis elbow of more than six months duration were randomly assigned to two active treatment groups. Group 1 (n = 29) received high-energy extracorporeal shock wave treatment (ESWT; 1,500 shocks) at 18 kV (0.22 mJ/mm2) without local anaesthesia; group 2 (n = 27) underwent percutaneous tenotomy of the common extensor origin. Both groups achieved improvement from the base line at three weeks, six weeks, 12 weeks and 12 months post-interven...

  12. 'Thunder' - Shock waves in pre-biological organic synthesis.

    Science.gov (United States)

    Bar-Nun, A.; Tauber, M. E.

    1972-01-01

    Theoretical study of the gasdynamics and chemistry of lightning-produced shock waves in a postulated primordial reducing atmosphere. It is shown that the conditions are similar to those encountered in a previously performed shock-tube experiment which resulted in 36% of the ammonia in the original mixture being converted into amino acids. The calculations give the (very large) energy rate of about 0.4 cal/sq cm/yr available for amino acid production, supporting previous hypotheses that 'thunder' could have been responsible for efficient large-scale production of organic molecules serving as precursors of life.

  13. 'Thunder' - Shock waves in pre-biological organic synthesis.

    Science.gov (United States)

    Bar-Nun, A.; Tauber, M. E.

    1972-01-01

    Theoretical study of the gasdynamics and chemistry of lightning-produced shock waves in a postulated primordial reducing atmosphere. It is shown that the conditions are similar to those encountered in a previously performed shock-tube experiment which resulted in 36% of the ammonia in the original mixture being converted into amino acids. The calculations give the (very large) energy rate of about 0.4 cal/sq cm/yr available for amino acid production, supporting previous hypotheses that 'thunder' could have been responsible for efficient large-scale production of organic molecules serving as precursors of life.

  14. A supercell, Bloch wave method for calculating low-energy electron reflectivity with applications to free-standing graphene and molybdenum disulfide

    Science.gov (United States)

    McClain, John

    This dissertation reports on a novel theoretical and computational framework for calculating low-energy electron reflectivities from crystalline surfaces and its application to two layered systems of two-dimensional materials, graphene and molybdenum disulfide. The framework provides a simple and efficient approach through the matching of a small set of Fourier components of Bloch wave solutions to the Schrodinger Equation in a slab-in-supercell geometry to incoming and outgoing plane waves on both sides of the supercell. The implementation of this method is described in detail for the calculation of reflectivities in the lowest energy range, for which only specular reflection is allowed. This implementation includes the calculation of reflectivities from beams with normal or off-normal incidence. Two different algorithms are described in the case of off-normal incidence which differ in their dependence on the existence of a symmetry with a mirror plane parallel to the crystal surface. Applications to model potentials in one, two, and three dimensions display consistent results when using different supercell sizes and convergent results with the density of Fourier grids. The design of the Bloch wave matching also allows for the accurate modeling of crystalline slabs through the use of realistic potentials determined via density functional theory. The application of the method to low-energy electron scattering from free-standing systems of a few layers of graphene, including the use of these realistic potentials, demonstrates this ability of the method to accurately model real systems. It reproduces the layer-dependent oscillations found in experimental, normal incidence reflectivity curves for a few layers of graphene grown on silicon carbide. The normal incidence reflectivity curves calculated for slabs consisting of few-layer graphene on 10 layers of nickel show some qualitative agreement with experiment. General incidence reflectivity spectra for free

  15. THE INTERACTION BETWEEN SHOCK WAVES AND FOAM IN A SHOCK TUBE

    Institute of Scientific and Technical Information of China (English)

    施红辉; Kazuhiko Kawai; Motoyuki Itoh; 俞鸿儒; 姜宗林

    2002-01-01

    An experimental study and a numerical simulation were conducted to investigate the mechanical and thermodynamic processes involved in the interaction between shock waves and low density foam. The experiment was done in a stainless shock tube (80 mm in inner diameter, 10 mm in wall thickness and 5 360 mm in length). The velocities of the incident and reflected compression waves in the foam were measured by using piezo-ceramic pressure sensors. The end-wall peak pressure behind the reflected wave in the foam was measured by using a crystal piezoelectric sensor. It is suggested that the high end-wall pressure may be caused by a rapid contact between the foam and the end-wall surface. Both open-cell and closed-cell foams with different length and density were tested. Through comparing the numerical and experimental end-wall pressure, the permeability coefficients α and β are quantitatively determined.

  16. Dynamic Response of Stiffened Plates with Holes Subjected to Shock Waves and Fragments

    Institute of Scientific and Technical Information of China (English)

    刘彦; 张庆明; 黄风雷

    2004-01-01

    The power field of shock waves and fragments is analyzed and set up, and the damage modes of stiffened plates are put forward. According to the structural characters of the stiffened plates investigated and the properties of the shock waves and fragments, the experiments on the shock waves acting on the stiffened plates (penetrated and non-penetrated by fragments) are mainly conducted. The dynamic response rules of stiffened plates with holes under shock waves and fragments loading are obtained. The results show that the penetration of fragments into stiffened plates hardly affects their deformation produced by shock waves.

  17. Second sound shock waves and critical velocities in liquid helium 2. Ph.D. Thesis

    Science.gov (United States)

    Turner, T. N.

    1979-01-01

    Large amplitude second-sound shock waves were generated and the experimental results compared to the theory of nonlinear second-sound. The structure and thickness of second-sound shock fronts are calculated and compared to experimental data. Theoretically it is shown that at T = 1.88 K, where the nonlinear wave steepening vanishes, the thickness of a very weak shock must diverge. In a region near this temperature, a finite-amplitude shock pulse evolves into an unusual double-shock configuration consisting of a front steepened, temperature raising shock followed by a temperature lowering shock. Double-shocks are experimentally verified. It is experimentally shown that very large second-sound shock waves initiate a breakdown in the superfluidity of helium 2, which is dramatically displayed as a limit to the maximum attainable shock strength. The value of the maximum shock-induced relative velocity represents a significant lower bound to the intrinsic critical velocity of helium 2.

  18. Shock-wave processing of C60 in hydrogen

    Science.gov (United States)

    Biennier, L.; Jayaram, V.; Suas-David, N.; Georges, R.; Singh, M. Kiran; Arunan, E.; Kassi, S.; Dartois, E.; Reddy, K. P. J.

    2017-02-01

    Context. Interstellar carbonaceous particles and molecules are subject to intense shocks in astrophysical environments. Shocks induce a rapid raise in temperature and density which strongly affects the chemical and physical properties of both the gas and solid phases of the interstellar matter. Aims: The shock-induced thermal processing of C60 particles in hydrogen has been investigated in the laboratory under controlled conditions up to 3900 K with the help of a material shock-tube. Methods: The solid residues generated by the exposure of a C60/H2 mixture to a millisecond shock wave were collected and analyzed using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman micro-spectroscopy, and infrared micro-spectroscopy. The gaseous products were analyzed by Gas Chromatography and Cavity Ring Down Spectroscopy. Results: Volatile end-products appear above reflected shock gas temperatures of 2540 K and reveal the substantial presence of small molecules with one or two C atoms. These observations confirm the role played by the C2 radical as a major product of C60 fragmentation and less expectedly highlight the existence of a single C atom loss channel. Molecules with more than two carbon atoms are not observed in the post-shock gas. The analysis of the solid component shows that C60 particles are rapidly converted into amorphous carbon with a number of aliphatic bridges. Conclusions: The absence of aromatic CH stretches on the IR spectra indicates that H atoms do not link directly to aromatic cycles. The fast thermal processing of C60 in H2 over the 800-3400 K temperature range leads to amorphous carbon. The analysis hints at a collapse of the cage with the formation of a few aliphatic connections. A low amount of hydrogen is incorporated into the carbon material. This work extends the range of applications of shock tubes to studies of astrophysical interest.

  19. Numerical Study of Shock Waves Propagating in an Elbow : 1st Report, A Rectangular Elbow

    OpenAIRE

    1993-01-01

    In this paper, the shock waves propagating in a rectangular elbow were investigated numerically in order to clarify how the transmitted shock wave past the elbow is stabilized to the uniform shock and the flow field induced by the shock. The computations were carried out by solving the two-dimensional compressible Navier-Stokes equations by means of the TVD finite difference method. The calculations were performed for three incident shock strengths and three Reynolds numbers of the flow, and ...

  20. Exploring nonlocal observables in shock wave collisions

    CERN Document Server

    Ecker, Christian; Stanzer, Philipp; Stricker, Stefan A; van der Schee, Wilke

    2016-01-01

    We study the time evolution of 2-point functions and entanglement entropy in strongly anisotropic, inhomogeneous and time-dependent N=4 super Yang-Mills theory in the large N and large 't Hooft coupling limit using AdS/CFT. On the gravity side this amounts to calculating the length of geodesics and area of extremal surfaces in the dynamical background of two colliding gravitational shockwaves, which we do numerically. We discriminate between three classes of initial conditions corresponding to wide, intermediate and narrow shocks, and show that they exhibit different phenomenology with respect to the nonlocal observables that we determine. Our results permit to use (holographic) entanglement entropy as an order parameter to distinguish between the two phases of the cross-over from the transparency to the full-stopping scenario in dynamical Yang-Mills plasma formation, which is frequently used as a toy model for heavy ion collisions. The time evolution of entanglement entropy allows to discern four regimes: hi...

  1. Multifluid, Magnetohydrodynamic Shock Waves with Grain Dynamics II. Dust and the Critical Speed for C Shocks

    CERN Document Server

    Ciolek, G E; Mouschovias, T C

    2004-01-01

    This is the second in a series of papers on the effects of dust on multifluid, MHD shock waves in weakly ionized molecular gas. We investigate the influence of dust on the critical shock speed, v_crit, above which C shocks cease to exist. Chernoff showed that v_crit cannot exceed the grain magnetosound speed, v_gms, if dust grains are dynamically well coupled to the magnetic field. We present numerical simulations of steady shocks where the grains may be well- or poorly coupled to the field. We use a time-dependent, multifluid MHD code that models the plasma as a system of interacting fluids: neutral particles, ions, electrons, and various ``dust fluids'' comprised of grains with different sizes and charges. Our simulations include grain inertia and grain charge fluctuations but to highlight the essential physics we assume adiabatic flow, single-size grains, and neglect the effects of chemistry. We show that the existence of a phase speed v_phi does not necessarily mean that C shocks will form for all shock s...

  2. EKSTRAKORPOREAL ŞOK DALGA TEDAVİSİ/EXTRACORPOREAL SHOCK WAVE THERAPY

    OpenAIRE

    2014-01-01

    Extracorporeal shock wave therapyExtracorporeal shock wave therapy (ESWT) is a therapy method which is applied acoustic pressure to thebody. Shock wave was first used in urology for renal stones in 1980s. Research has been started in orthopedicsin 1990s. Today it has been used for most of the diagnosis in different clinics. In this review it has summarizedthat the action mechanism, indications, contraindications, complications and current studies in the literatureabout extracorporeal shock wa...

  3. Ion streaming instabilities with application to collisionless shock wave structure

    Science.gov (United States)

    Golden, K. I.; Linson, L. M.; Mani, S. A.

    1973-01-01

    The electromagnetic dispersion relation for two counterstreaming ion beams of arbitrary relative strength flowing parallel to a dc magnetic field is derived. The beams flow through a stationary electron background and the dispersion relation in the fluid approximation is unaffected by the electron thermal pressure. Magnetic effects on the ion beams are included, but the electrons are treated as a magnetized fluid. The dispersion relation is solved with a zero net current condition applied and the regions of instability in the k-U space (U is the relative velocity between the two ion beams) are presented. These results are extensions of Kovner's analysis for weak beams. The parameters are then chosen to be applicable for parallel shocks. It is found that unstable waves with zero group velocity in the shock frame can exist near the leading edge of the shock for upstream Alfven Mach numbers greater than 5.5.

  4. Shock induced damage and damage threshold of optical K9 glass investigated by laser-driven shock wave

    Science.gov (United States)

    Song, Yunfei; Yu, Guoyang; Jiang, Lilin; Zheng, Xianxu; Liu, Yuqiang; Yang, Yanqiang

    2011-04-01

    The shock wave driven by short laser pulse is used to study the damage of brittle material K9 glass. The damage morphology of K9 glass surface indicates that the material has experienced different loading modes, respectively, at the central area and the surrounding area of the shock wave. At the central area of shock wave, the wavefront is plane and has a uniform pressure distribution, the material mainly suffers a longitudinal shock pressure; but on the edge the shock wave, the wavefront is approximately spherical, besides longitudinal pressure, transverse tensile stress will emerge inside the material. In the latter case, the damage threshold of the material is much smaller than that in the case of compressing by longitudinal pressure only. According to the relationship between damage area and shock pressure, an experimental method is proposed to measure the damage threshold of materials under shock loading. The damage threshold of K9 glass under spherical shock wave is measured to be about 1.12 GPa; and the damage threshold under plane shock wave is estimated to be between 1.82 and 1.98 GPa. They are much bigger than the damage threshold under static pressure. This method could also be used to measure the damage threshold of other materials when loaded by dynamic pressure.

  5. Optical dispersive shock waves in defocusing colloidal media

    Science.gov (United States)

    An, X.; Marchant, T. R.; Smyth, N. F.

    2017-03-01

    The propagation of an optical dispersive shock wave, generated from a jump discontinuity in light intensity, in a defocusing colloidal medium is analysed. The equations governing nonlinear light propagation in a colloidal medium consist of a nonlinear Schrödinger equation for the beam and an algebraic equation for the medium response. In the limit of low light intensity, these equations reduce to a perturbed higher order nonlinear Schrödinger equation. Solutions for the leading and trailing edges of the colloidal dispersive shock wave are found using modulation theory. This is done for both the perturbed nonlinear Schrödinger equation and the full colloid equations for arbitrary light intensity. These results are compared with numerical solutions of the colloid equations.

  6. Material measurement method based on femtosecond laser plasma shock wave

    Science.gov (United States)

    Zhong, Dong; Li, Zhongming

    2017-03-01

    The acoustic emission signal of laser plasma shock wave, which comes into being when femtosecond laser ablates pure Cu, Fe, and Al target material, has been detected by using the fiber Fabry-Perot (F-P) acoustic emission sensing probe. The spectrum characters of the acoustic emission signals for three kinds of materials have been analyzed and studied by using Fourier transform. The results show that the frequencies of the acoustic emission signals detected from the three kinds of materials are different. Meanwhile, the frequencies are almost identical for the same materials under different ablation energies and detection ranges. Certainly, the amplitudes of the spectral character of the three materials show a fixed pattern. The experimental results and methods suggest a potential application of the plasma shock wave on-line measurement based on the femtosecond laser ablating target by using the fiber F-P acoustic emission sensor probe.

  7. Renal pelvic stones: choosing shock wave lithotripsy or percutaneous nephrolithotomy

    Directory of Open Access Journals (Sweden)

    Robert Marcovich

    2003-06-01

    Full Text Available Introduction of minimally invasive techniques has revolutionized the surgical management of renal calculi. Extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy are now both well-established procedures. Each modality has advantages and disadvantages, and the application of each should be based on well-defined factors. These variables include stone factors such as number, size, and composition; factors related to the stone's environment, including the stone's location, spatial anatomy of the renal collecting system, presence of hydronephrosis, and other anatomic variables, such as the presence of calyceal diverticula and renal anomalies; and clinical or patient factors like morbid obesity, the presence of a solitary kidney, and renal insufficiency. The morbidity of each procedure in relation to its efficacy should be taken in to account. This article will review current knowledge and suggest an algorithm for the rational management of renal calculi with shock wave lithotripsy and percutaneous nephrolithotomy.

  8. Shock Wave Attenuation Using Foam Obstacles: Does Geometry Matter?

    Directory of Open Access Journals (Sweden)

    Hongjoo Jeon

    2015-06-01

    Full Text Available A shock wave impact study on open and closed cell foam obstacles was completed to assess attenuation effects with respect to different front face geometries of the foam obstacles. Five different types of geometries were investigated, while keeping the mass of the foam obstacle constant. The front face, i.e., the side where the incident shock wave impacts, were cut in geometries with one, two, three or four convergent shapes, and the results were compared to a foam block with a flat front face. Results were obtained by pressure sensors located upstream and downstream of the foam obstacle, in addition to high-speed schlieren photography. Results from the experiments show no significant difference between the five geometries, nor the two types of foam.

  9. Clusters of Galaxies Shock Waves and Cosmic Rays

    CERN Document Server

    Ryu, D; Ryu, Dongsu; Kang, Hyesung

    2002-01-01

    Recent observations of galaxy clusters in radio and X-ray indicate that cosmic rays and magnetic fields may be energetically important in the intracluster medium. According to the estimates based on theses observational studies, the combined pressure of these two components of the intracluster medium may range between $10% \\sim 100 %$ of gas pressure, although their total energy is probably time dependent. Hence, these non-thermal components may have influenced the formation and evolution of cosmic structures, and may provide unique and vital diagnostic information through various radiations emitted via their interactions with surrounding matter and cosmic background photons. We suggest that shock waves associated with cosmic structures, along with individual sources such as active galactic nuclei and radio galaxies, supply the cosmic rays and magnetic fields to the intracluster medium and to surrounding large scale structures. In order to study 1) the properties of cosmic shock waves emerging during the larg...

  10. Simulation and Analysis of Converging Shock Wave Test Problems

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, Scott D. [Los Alamos National Laboratory; Shashkov, Mikhail J. [Los Alamos National Laboratory

    2012-06-21

    Results and analysis pertaining to the simulation of the Guderley converging shock wave test problem (and associated code verification hydrodynamics test problems involving converging shock waves) in the LANL ASC radiation-hydrodynamics code xRAGE are presented. One-dimensional (1D) spherical and two-dimensional (2D) axi-symmetric geometric setups are utilized and evaluated in this study, as is an instantiation of the xRAGE adaptive mesh refinement capability. For the 2D simulations, a 'Surrogate Guderley' test problem is developed and used to obviate subtleties inherent to the true Guderley solution's initialization on a square grid, while still maintaining a high degree of fidelity to the original problem, and minimally straining the general credibility of associated analysis and conclusions.

  11. Shock-Wave Consolidation of Nanostructured Bismuth Telluride Powders

    Science.gov (United States)

    Beck, Jan; Alvarado, Manuel; Nemir, David; Nowell, Mathew; Murr, Lawrence; Prasad, Narasimha

    2012-06-01

    Nanostructured thermoelectric powders can be produced using a variety of techniques. However, it is very challenging to build a bulk material from these nanopowders without losing the nanostructure. In the present work, nanostructured powders of the bismuth telluride alloy system are obtained in kilogram quantities via a gas atomization process. These powders are characterized using a variety of methods including scanning electron microscopy, transition electron microscopy, and x-ray diffraction analysis. Then the powders are consolidated into a dense bulk material using a shock-wave consolidation technique whereby a nanopowder-containing tube is surrounded by explosives and then detonated. The resulting shock wave causes rapid fusing of the powders without the melt and subsequent grain growth of other techniques. We describe the test setup and consolidation results.

  12. Extracorporeal shock wave therapy in periodontics: A new paradigm.

    Science.gov (United States)

    Venkatesh Prabhuji, Munivenkatappa Lakshmaiah; Khaleelahmed, Shaeesta; Vasudevalu, Sujatha; Vinodhini, K

    2014-05-01

    The quest for exploring new frontiers in the field of medical science for efficient and improved treatment modalities has always been on a rise. Extracorporeal shock wave therapy (ESWT) has been enormously used in medical practice, principally, for the management of urolithiasis, cholelithiasis and also in various orthopedic and musculoskeletal disorders. The efficacy of ESWT in the stimulation of osteoblasts, fibroblasts, induction of neovascularization and increased expression of bone morphogenic proteins has been well documented in the literature. However, dentistry is no exception to this trend. The present article enlightens the various applications of ESWT in the field of dentistry and explores its prospective applications in the field of periodontics, and the possibility of incorporating the beneficial properties of shock waves in improving the treatment outcome.

  13. Extracorporeal shock wave therapy in periodontics: A new paradigm

    Directory of Open Access Journals (Sweden)

    Munivenkatappa Lakshmaiah Venkatesh Prabhuji

    2014-01-01

    Full Text Available The quest for exploring new frontiers in the field of medical science for efficient and improved treatment modalities has always been on a rise. Extracorporeal shock wave therapy (ESWT has been enormously used in medical practice, principally, for the management of urolithiasis, cholelithiasis and also in various orthopedic and musculoskeletal disorders. The efficacy of ESWT in the stimulation of osteoblasts, fibroblasts, induction of neovascularization and increased expression of bone morphogenic proteins has been well documented in the literature. However, dentistry is no exception to this trend. The present article enlightens the various applications of ESWT in the field of dentistry and explores its prospective applications in the field of periodontics, and the possibility of incorporating the beneficial properties of shock waves in improving the treatment outcome.

  14. Dark solitons, dispersive shock waves, and transverse instabilities

    CERN Document Server

    Hoefer, M A

    2011-01-01

    The nature of transverse instabilities to dark solitons and dispersive shock waves for the (2+1)-dimensional defocusing nonlinear Schrodinger equation / Gross-Pitaevskii (NLS / GP) equation is considered. Special attention is given to the small (shallow) amplitude regime, which limits to the Kadomtsev-Petviashvili (KP) equation. We study analytically and numerically the eigenvalues of the linearized NLS / GP equation. The dispersion relation for shallow solitons is obtained asymptotically beyond the KP limit. This yields 1) the maximum growth rate and associated wavenumber of unstable perturbations; and 2) the separatrix between convective and absolute instabilities. The latter result is used to study the transition between convective and absolute instabilities of oblique dispersive shock waves (DSWs). Stationary and nonstationary oblique DSWs are constructed analytically and investigated numerically by direct simulations of the NLS / GP equation. The instability properties of oblique DSWs are found to be dir...

  15. Primordial gas cooling behind shock waves in merging halos

    CERN Document Server

    Vasiliev, E O; Shchekinov, Yu.A.

    2006-01-01

    We investigate thermal regime of the baryons behind shock waves arising in the process of virialization of dark matter halos. We find a fraction of the shocked gas cooled by radiation of HD molecules down to the temperature of the cosmic microwave background (CMB): this fraction increases sharply from about $f_{\\rm c}\\sim 10^{-3}$ for dark halos of $M=5\\times 10^7\\msun$ to $\\sim 0.1$ for halos with $M=10^8\\msun$ at $z=10$. We show, however, that further increase of the mass does not lead to a significant growth of $f_{\\rm c}$ -- the assymptotic value for $M\\gg 10^8\\msun$ is of 0.2. We estimate star formation rate associated with such shock waves, and show that it can be a small but not negligible fraction of the star formation connected with cooling by HI and H$_2$. We argue that extremely metal-poor low-mass stars in the Milky Way may have been formed from primordial gas behind such shocks.

  16. Temperature kinetics during shock-wave consolidation of metallic powders

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, R.B.; Kasiraj, P.; Vreeland, T. Jr.

    1985-01-01

    Powders (60 ..mu..m diam) of constantan and pure copper were compressed statically into cylindrical greens (20.3 mm diam, 5.3 mm long) with a flat interface separating the two powders. A 20-mm propellant gun was used to accelerate a flyer of Lexan, copper, or aluminum, and generate in the green a shock wave with front parallel to the Cu/constantan interface. The voltages between opposite ends of the greens were measured as a function of time and for shock pressures between 1.3 and 9.4 GPa. When the shock wave arrives at the Cu/constantan interface, the voltage signal shows an abrupt increase, which lasts between 45 and 81 ns and leads to a peak temperature T/sub p/. After this, the hotter and cooler parts of the compact equilibrate and the temperature decreases to a value T/sub h/. With increasing shock pressure, T/sub h/ increases from 425 to 1215 K. The measurements of T/sub h/ are in excellent agreement with the temperatures calculated from the measured flyer velocity, the Hugoniot for copper powder, and thermodynamic data for the flyer and powders.

  17. On the propagation of sound waves in a stellar wind traversed by periodic strong shocks

    OpenAIRE

    Pijpers, F. P.

    1994-01-01

    It has been claimed that in stellar winds traversed by strong shocks the mechanism for driving the wind by sound wave pressure cannot operate because sound waves cannot propagate past the shocks. It is shown here that sound waves can propagate through shocks in one direction and that this is a sufficient condition for the sound wave pressure mechanism to work. A strong shock amplifies a sound wave passing through it and can drag the sound wave away from the star. It is immaterial for the soun...

  18. Simulation of hypersonic shock wave - laminar boundary layer interactions

    Science.gov (United States)

    Kianvashrad, N.; Knight, D.

    2017-06-01

    The capability of the Navier-Stokes equations with a perfect gas model for simulation of hypersonic shock wave - laminar boundary layer interactions is assessed. The configuration is a hollow cylinder flare. The experimental data were obtained by Calspan-University of Buffalo (CUBRC) for total enthalpies ranging from 5.07 to 21.85 MJ/kg. Comparison of the computed and experimental surface pressure and heat transfer is performed and the computed §ow¦eld structure is analyzed.

  19. Patient information leaflets for extracorporeal shock wave lithotripsy: questionnaire survey

    OpenAIRE

    Askari, A.; Shergill, I.

    2012-01-01

    Objectives To compare the level of information provided in extracorporeal shock wave lithotripsy (ESWL) patient information leaflets in the London and East of England Deaneries Design All trusts in the London and East of England Deanery who offer an ESWL service were contacted and leaflets were compared Setting London and East of England Deanery Participants Alan Askari, Iqbal Shergill Main outcome measures Examination of key information that was communicated to ESWL patients via leaflets Res...

  20. Renal pelvic stones: choosing shock wave lithotripsy or percutaneous nephrolithotomy

    OpenAIRE

    Robert Marcovich; Smith, Arthur D.

    2003-01-01

    Introduction of minimally invasive techniques has revolutionized the surgical management of renal calculi. Extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy are now both well-established procedures. Each modality has advantages and disadvantages, and the application of each should be based on well-defined factors. These variables include stone factors such as number, size, and composition; factors related to the stone's environment, including the stone's location, spatial...

  1. Kidney changes after extracorporeal shock wave lithotripsy; MR evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshioka, Hiroyasu; Shindo, Hiroshi; Mabuchi, Nobuhisa; Kawakami, Akira; Fujii, Koichi; Hamada, Tatsumi; Ishida, Osamu; Umekawa, Toru; Kohri, Kenjiro (Kinki Univ., Osakasayama, Osaka (Japan). School of Medicine)

    1991-02-01

    MRI was performed before and after extracorporeal shock wave lithotripsy (ESWL) to determine the effects of ESWL on the kidney and perinephric tissues. Of the 40 kidneys studied, 24 showed one or more changes on MRI: loss of the corticomedullary junction (n=15), subcapsular fluid (n=14), subcapsular hematoma (n=1), thickening of bridging septa (n=8), high intensity area in the muscle (n=8). These relatively subtle changes detected on MRI may not be apparent with other imaging techniques. (author).

  2. Shock wave therapy for chronic proximal plantar fasciitis.

    Science.gov (United States)

    Ogden, J A; Alvarez, R; Levitt, R; Cross, G L; Marlow, M

    2001-06-01

    Three hundred two patients with chronic heel pain caused by proximal plantar fasciitis were enrolled in a study to assess the treatment effects consequent to administration of electrohydraulicall-generated extracorporeal shock waves. Symptoms had been present from 6 months to 18 years. Each treated patient satisfied numerous inclusion and exclusion criteria before he or she was accepted into this study, which was approved by the Food and Drug Administration as a randomized, double-blind evaluation of the efficacy of shock wave therapy for this disorder. Overall, at the predetermined evaluation period 3 months after one treatment, 56% more of the treated patients had a successful result by all four of the evaluation criteria when compared with the patients treated with a placebo. This difference was significant and corroborated the fact that this difference in the results was specifically attributable to the shock wave treatment, rather than any natural improvement caused by the natural history of the condition. The current study showed that the directed application of electrohydraulic-generated shock waves to the insertion of the plantar fascia onto the calcaneus is a safe and effective nonsurgical method for treating chronic, recalcitrant heel pain syndrome that has been present for at least 6 months and has been refractory to other commonly used nonoperative therapies. This technology, when delivered using the OssaTron (High Medical Technology, Kreuz-lingen, Switzerland), has been approved by the Food and Drug Administration specifically for the treatment of chronic proximal plantar fasciitis. The results suggest that this therapeutic modality should be considered before any surgical options, and even may be preferable to cortisone injection, which has a recognized risk of rupture of the plantar fascia and recurrence of symptoms.

  3. Plasmonic shock waves and solitons in a nanoring

    OpenAIRE

    2016-01-01

    We apply the hydrodynamic theory of electron liquid to demonstrate that a circularly polarized radiation induces the diamagnetic, helicity-sensitive dc current in a ballistic nanoring. This current is dramatically enhanced in the vicinity of plasmonic resonances. The resulting magnetic moment of the nanoring represents a giant increase of the inverse Faraday effect. With increasing radiation intensity, linear plasmonic excitations evolve into the strongly non-linear plasma shock waves. These ...

  4. Pediatric extracorporeal shock wave lithotripsy: Predicting successful outcomes.

    Science.gov (United States)

    McAdams, Sean; Shukla, Aseem R

    2010-10-01

    Extracorporeal shock wave lithotripsy (ESWL) is currently a first-line procedure of most upper urinary tract stones ionizing radiation, perhaps utilizing advancements in ultrasound and magnetic resonance imaging. This report provides a review of the current literature evaluating the patient attributes and stone factors that may be predictive of successful ESWL outcomes along with reviewing the role of pre-operative imaging and considerations for patient safety.

  5. Methodology of the joint search for Gravitational Wave and Low Energy Neutrino signals from Core-Collapse Supernovae

    Science.gov (United States)

    Casentini, Claudio

    2016-05-01

    Core-Collapse Supernovae (CCSNe) have a neutrino (v) signature confirmed by SN 1987A and are potential sources of Gravitational Waves (GWs). vs and GWs coming from these sources will reach the observer almost simultaneously and without significant interaction with interstellar matter. The expected GW signals are in the range of the upcoming advanced detectors for galactic neighborhood events. However, there are still significant uncertainties on the theoretical model of the emission. A joint search of coincident vs and GWs from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent Supernovae. Recently, a project for a joint search involving GW interferometers and v detectors has started. In this paper we discuss about the principal GW theoretical models of emission, and we present a methodological study of the joint search project between GW and v.

  6. Triple-layer Absorptive Structures for Shock Wave Blast Protection

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Triple-layer absorptive structure is designed to reinforce a missile silo against shock wave blasts. An energy-absorbing layer and a cushion layer overlay the circular silo cover made of reinforced concrete. The dynamic stress analysis is performed by ABAQUS/Explicit. The mesoscopic structure of the energy absorbing layer is designed as an assembly of ductile tubes containing crushable cellular ceramics. Combined mesoscopic and macroscopic simulations indicate that the structure can enhance the survivability of a missile silo against blast waves.

  7. Investigating Vaporization of Silica through Laser Driven Shock Wave Experiments

    Science.gov (United States)

    Kraus, R. G.; Swift, D. C.; Stewart, S. T.; Smith, R.; Bolme, C. A.; Spaulding, D. K.; Hicks, D.; Eggert, J.; Collins, G.

    2010-12-01

    Giant impacts melt and vaporize a significant amount of the bolide and target body. However, our ability to determine how much melt or vapor a given impact creates depends strongly on our understanding of the liquid-vapor phase boundary of geologic materials. Our current knowledge of the liquid-vapor equilibrium for one of the most important minerals, SiO2, is rather limited due to the difficulty of performing experiments in this area of phase space. In this study, we investigate the liquid-vapor coexistence region by shocking quartz into a supercritical fluid state and allowing it to adiabatically expand to a state on the liquid-vapor phase boundary. Although shock compression and release has been used to study the liquid-vapor equilibrium of metals [1], few attempts have been made at studying geologic materials by this method [2]. Shock waves were produced by direct ablation of the quartz sample using the Jupiter Laser Facility of Lawrence Livermore National Laboratory. Steady shock pressures of 120-360 GPa were produced in the quartz samples: high enough to force the quartz into a supercritical fluid state. As the shock wave propagates through the sample, we measure the shock velocity using a line imaging velocity interferometer system for any reflector (VISAR) and shock temperature using a streaked optical pyrometer (SOP). When the shock wave reaches the free surface of the sample, the material adiabatically expands. Upon breakout of the shock at the free surface, the SOP records a distinct drop in radiance due to the lower temperature of the expanded material. For a subset of experiments, a LiF window is positioned downrange of the expanding silica. When the expanding silica impacts the LiF window, the velocity at the interface between the expanding silica and LiF window is measured using the VISAR. From the shock velocity measurements, we accurately determine the shocked state in the quartz. The post-shock radiance measurements are used to constrain the

  8. Stability of stagnation via an expanding accretion shock wave

    CERN Document Server

    Velikovich, A L; Taylor, B D; Giuliani, J L; Zalesak, S T; Iwamoto, Y

    2016-01-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Y. Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [H. Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); M. Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic...

  9. Stability of stagnation via an expanding accretion shock wave

    Science.gov (United States)

    Velikovich, A. L.; Murakami, M.; Taylor, B. D.; Giuliani, J. L.; Zalesak, S. T.; Iwamoto, Y.

    2016-05-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  10. A study on compressive shock wave propagation in metallic foams

    Science.gov (United States)

    Wang, Zhihua; Zhang, Yifen; Ren, Huilan; Zhao, Longmao

    2010-02-01

    Metallic foam can dissipate a large amount of energy due to its relatively long stress plateau, which makes it widely applicable in the design of structural crashworthiness. However, in some experimental studies, stress enhancement has been observed when the specimens are subjected to intense impact loads, leading to severe damage to the objects being protected. This paper studies this phenomenon on a 2D mass-spring-bar model. With the model, a constitutive relationship of metal foam and corresponding loading and unloading criteria are presented; a nonlinear kinematics equilibrium equation is derived, where an explicit integration algorithm is used to calculate the characteristic of the compressive shock wave propagation within the metallic foam; the effect of heterogeneous distribution of foam microstructures on the shock wave features is also included. The results reveal that under low impact pulses, considerable energy is dissipated during the progressive collapse of foam cells, which then reduces the crush of objects. When the pulse is sufficiently high, on the other hand, stress enhancement may take place, especially in the heterogeneous foams, where high peak stresses usually occur. The characteristics of compressive shock wave propagation in the foam and the magnitude and location of the peak stress produced are strongly dependent on the mechanical properties of the foam material, amplitude and period of the pulse, as well as the homogeneity of the microstructures. This research provides valuable insight into the reliability of the metallic foams used as a protective structure.

  11. Impact-driven shock waves and thermonuclear neutron generation

    Energy Technology Data Exchange (ETDEWEB)

    Gus' kov, S Yu; Demchenko, N N; Doskoch, I Ya; Rozanov, V B [P.N. Lebedev Physical Institute of Russian Academy of Sciences, Moscow (Russian Federation); Azechi, H; Murakami, M; Sakaiya, T; Watari, T [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Zmitrenko, N V, E-mail: guskov@sci.lebedev.r [Institute for Mathematical Modeling of Russian Academy of Sciences, Moscow (Russian Federation)

    2009-09-15

    Impact-driven shock waves, thermonuclear plasma and neutron yield were investigated. The results of 2D numerical simulations and Gekko/HIPER laser experiments on the collision of a laser-accelerated disk-projectile with a massive target, both containing (CD){sub n}-material, are discussed. A two-temperature model of the non-equilibrium plasma created by impact-driven shock waves due to the collision of a laser-accelerated planar projectile with a massive target was developed and used for analysis of the numerical and experimental results. The model defines the characteristics of shock waves and plasmas (including their lifetime) as well as neutron yields in both the colliding objects as functions of velocity, density and mass of the projectile-impactor just before collision. The neutron yield generated during the period of laser-driven acceleration of the impactor was also determined. Two effects were discovered that exert a substantial influence on the plasma parameters and neutron yield. The first of them relates to the formation of the pre-impact state of the impactor. It decreases the projectile density due to thermal expansion of its matter through a free boundary during the period of laser-driven acceleration. The other relates to the formation of impact-produced plasma. Predominant heating of the ion component of plasma leads to the existence of a non-equilibrium two-temperature plasma during the period of electron-ion relaxation.

  12. Shoulder function after extracorporal shock wave therapy for calcific tendinitis.

    Science.gov (United States)

    Rompe, J D; Bürger, R; Hopf, C; Eysel, P

    1998-01-01

    We report a controlled, prospective study that explored the effect of extracorporal shock waves of low- versus high-energy density in patients with chronic shoulder pain and calcific tendinitis. We assigned at random 100 patients who had had calcific tendinitis for more than 12 months to 2 groups to receive shock wave therapy either of a low- or high-energy density. Group 1 received 1500 impulses of 0.06 mJ/mm2, whereas group 2 received 1500 impulses of 0.28 mJ/mm2. Unlike group 1, in which the shock wave application could be performed without local anesthesia, all patients in group 2 required brachial plexus anesthesia. The patients were reviewed at 6 and 24 weeks. Partial or complete disintegration of the calcareous deposit was observed in 50% of the patients in group 1 and 64% of the patients in group 2 (P < .01). According to the Constant score, ratings increased from 48 to 71 points in group 1 (P < .001) and from 53 to 88 in group 2 (P < .001) (out of a total possible 100 points), the end values of both groups differing significantly (P < .01). After 24 weeks, 52% of the patients in group 1 rated the results of treatment as good or excellent, compared with 68% in group 2 (P < .01). No improvement was reported by 24% versus 10%, respectively, at the 24-week follow-up.

  13. Treatment of lateral epicondylitis of the elbow with shock waves.

    Science.gov (United States)

    Ko, J Y; Chen, H S; Chen, L M

    2001-06-01

    In a prospective clinical study, the effectiveness of shock wave treatment for lateral epicondylitis in 56 elbows in 53 patients (27 men and 26 women) with an average age of 46 years was investigated. Three patients received treatment for both elbows. Each elbow was treated with 1,000 impulses of shock waves at 14 kV. A 100-point scoring system was used for evaluation including 40 points for pain, 30 points for function, 20 points for strength, and 10 points for elbow motion. The intensity of pain was measured using a visual analogue scale from 0 to 10. The overall results were 13.2% excellent, 44.7% good, 36.8% acceptable, and 5.3 unchanged in 35 patients with 12 weeks followup; 30.8% excellent, 42.3% good, and 26.9% acceptable in 25 patients with 24 weeks followup. Considerable improvement was observed from 6 weeks to 6 months after the treatment. None of the patients' symptoms became worse. The results of nine patients who also received a second treatment were good in three patients, acceptable in five patients, and unchanged in one patient. There was no device-related problems, systemic, or local complications. Shock wave therapy may offer a new and safer nonoperative treatment for patients with lateral epidoncylitis of the elbow.

  14. Stability of stagnation via an expanding accretion shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Velikovich, A. L.; Giuliani, J. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Taylor, B. D. [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC 20375 (United States); Zalesak, S. T. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States); Iwamoto, Y. [Ehime University, Matsuyama, Ehime Pref. 790-8577 (Japan)

    2016-05-15

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  15. Convergence of shock waves between conical and parabolic boundaries

    Science.gov (United States)

    Yanuka, D.; Zinowits, H. E.; Antonov, O.; Efimov, S.; Virozub, A.; Krasik, Ya. E.

    2016-07-01

    Convergence of shock waves, generated by underwater electrical explosions of cylindrical wire arrays, between either parabolic or conical bounding walls is investigated. A high-current pulse with a peak of ˜550 kA and rise time of ˜300 ns was applied for the wire array explosion. Strong self-emission from an optical fiber placed at the origin of the implosion was used for estimating the time of flight of the shock wave. 2D hydrodynamic simulations coupled with the equations of state of water and copper showed that the pressure obtained in the vicinity of the implosion is ˜7 times higher in the case of parabolic walls. However, comparison with a spherical wire array explosion showed that the pressure in the implosion vicinity in that case is higher than the pressure in the current experiment with parabolic bounding walls because of strong shock wave reflections from the walls. It is shown that this drawback of the bounding walls can be significantly minimized by optimization of the wire array geometry.

  16. How the Term "Shock Waves" Came Into Being

    Science.gov (United States)

    Fomin, N. A.

    2016-07-01

    The present paper considers the history of works on shock waves beginning from S. D. Poisson's publication in 1808. It expounds on the establishment of the Polytechnic School in Paris and its fellows and teachers — Gaspard Monge, Lazare Carnot, Joseph Louis Gay-Lussac, Simeon Denis Poisson, Henri Navier, Augustin Louis Cauchy, Joseph Liouville, Ademar de Saint-Venant, Henri Regnault, Pierre Dulong, Emile Jouguet, Pierre Duhem, and others. It also describes the participation in the development of the shock wave theory of young scientists from the universities of Cambridge, among which were George Airy, James Challis, Samuel Earnshaw, George Stokes, Lord Rayleigh, Lord Kelvin, and James Maxwell, as well as of scientists from the Göttingen University, Germany — Bernhard Riemann and Ernst Heinrich Weber. The pioneer works on shock waves of the Scottish engineer William Renkin, the French artillerist Pierre-Henri Hugoniot, German scientists August Toepler and Ernst Mach, and a Hungarian scientist Gyözö Zemplén are also considered.

  17. The effects of shock wave and quasi-traveling wave in the mechanical impact test

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is well-known that the numerical value is always larger than the measured value,amounting to many times,if we calculate the stress of the specimen in the impulse test using the NASTRAN and ANSYS (N-A) software.We believe that the impact induces shock wave or quasi-traveling wave in the specimen,which can qualitatively explain the discrepancy of the two values.In order to verify it,the Lax-Friedrichs (L-F) scheme is taken to simulate the transmission of shock wave and quasi-traveling wave in solid.Numerical results show that the action area of the stress wave is small and the action time is very short,so the resulting stress and actual work are not big.In addition,the distribution of the impact values obtained by the numerical simulation is in accordance with the trend of the measured impact values.

  18. Shock Wave Propagation in Cementitious Materials at Micro/Meso Scales

    Science.gov (United States)

    2015-08-31

    ABSTRACT 16. SECURITY CLASSIFICATION OF: Shock wave response of heterogeneous materials like cement and concrete is greatly influenced by the...2015 Approved for public release; distribution is unlimited. Shock Wave Propagation in Cementitious Materials at Micro/Meso Scales The views...Box 12211 Research Triangle Park, NC 27709-2211 shock propagation, micro and macro scales, finite element modeling REPORT DOCUMENTATION PAGE 11

  19. Experimental Study on Shock Wave Structures in Constant-area Passage of Cold Spray Nozzle

    Institute of Scientific and Technical Information of China (English)

    Hiroshi KATANODA; Takeshi MATSUOKA; Kazuyasu MATSUO

    2007-01-01

    Cold spray is a technique to make a coating on a wide variety of mechanical or electric parts by spraying solid particles accelerated through a high-speed gas flow in a converging-diverging nozzle. In this study, pseudo-shock waves in a modeled cold spray nozzle as well as high-speed gas jets are visualized by schlieren technique. The schlieren photographs reveals the supersonic flow with shock train in the nozzle. Static pressure along the barrel wall is also measured. The location of the head of pseudo-shock wave and its pressure distribution along the nozzle wall are analytically explained by using a formula of pseudo-shock wave. The analytical results show that the supersonic flow accompanying shock wave in the nozzle should be treated as pseudo-shock wave instead of normal shock wave.

  20. Some recent advances of shock wave physics research at the Laboratory for Shock Wave and Detonation Physics Research

    CERN Document Server

    Jing Fu Qian

    2002-01-01

    Progress made in recent years on three topics that have been investigated at the Laboratory for Shock Wave and Detonation Physics Research are presented in this report. (1) A new equation of state (EOS) has been derived which can be used from a standard state to predict state variable change along an isobaric path. Good agreements between calculations for some representative metals using this new EOS and experiments have been found, covering a wide range from hundreds of MPa to hundreds of GPa and from ambient temperature to tens of thousands of GPa. (2) An empirical relation of Y/G = constant (Y is yield strength, G is shear modulus) at HT-HP has been reinvestigated and confirmed by shock wave experiment. 93W alloy was chosen as a model material. The advantage of this relation is that it is beneficial to formulate a kind of simplified constitutive equation for metallic solids under shock loading, and thus to faithfully describe the behaviours of shocked solids through hydrodynamic simulations. (3) An attempt...

  1. Development of Extracorporeal Shock Wave Therapy for the Treatment for Ischemic Cardiovascular Diseases

    Science.gov (United States)

    Shimokawa, Hiroaki

    Cardiovascular diseases, such as coronary artery disease and peripheral artery disease, are the major causes of death in developed countries, and the number of elderly patients has been rapidly increasing worldwide. Thus, it is crucial to develop new non-invasive therapeutic strategies for these patients. We found that a low-energy shock wave (SW) (about 10% of the energy density that is used for urolithiasis) effectively increases the expression of vascular endothelial growth factor (VEGF) in cultured endothelial cells. Subsequently, we demonstrated that extracorporeal cardiac SW therapy with low-energy SW up-regulates the expression of VEGF, enhances angiogenesis, and improves myocardial ischemia in a pig model of chronic myocardial ischemia without any adverse effects in vivo. Based on these promising results in animal studies, we have subsequently developed a new, non-invasive angiogenic therapy with low-energy SW for cardiovascular diseases. Our extracorporeal cardiac SW therapy improved symptoms and myocardial perfusion evaluated with stress-scintigraphy in patients with severe coronary artery disease without indication of percutaneous coronary intervention or coronary artery bypass surgery. Importantly, no procedural complications or adverse effects were noted. The SW therapy was also effective in ameliorating left ventricular remodeling after acute myocardial infarction in pigs and in enhancing angiogenesis in hindlimb ischemia in animals and patients with coronary artery disease. Furthermore, our recent experimental studies suggest that the SW therapy is also effective for indications other than cardiovascular diseases. Thus, our extracorporeal cardiac SW therapy is an effective, safe, and non-invasive angiogenic strategy for cardiovascular medicine.

  2. Experimental particle acceleration by water evaporation induced by shock waves

    Science.gov (United States)

    Scolamacchia, T.; Alatorre Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Cimarelli, C.

    2010-12-01

    Shock waves are commonly generated during volcanic eruptions. They induce sudden changes in pressure and temperature causing phase changes. Nevertheless, their effects on flowfield properties are not well understood. Here we investigate the role of gas expansion generated by shock wave propagation in the acceleration of ash particles. We used a shock tube facility consisting of a high-pressure (HP) steel autoclave (450 mm long, 28 mm in internal diameter), pressurized with Ar gas, and a low-pressure tank at atmospheric conditions (LP). A copper diaphragm separated the HP autoclave from a 180 mm tube (PVC or acrylic glass) at ambient P, with the same internal diameter of the HP reservoir. Around the tube, a 30 cm-high acrylic glass cylinder, with the same section of the LP tank (40 cm), allowed the observation of the processes occurring downstream from the nozzle throat, and was large enough to act as an unconfined volume in which the initial diffracting shock and gas jet expand. All experiments were performed at Pres/Pamb ratios of 150:1. Two ambient conditions were used: dry air and air saturated with steam. Carbon fibers and glass spheres in a size range between 150 and 210 μm, were placed on a metal wire at the exit of the PVC tube. The sudden decompression of the Ar gas, due to the failure of the diaphragm, generated an initial air shock wave. A high-speed camera recorded the processes between the first 100 μsec and several ms after the diaphragm failure at frame rates ranging between 30,000 and 50,000 fps. In the experiments with ambient air saturated with steam, the high-speed camera allowed to visualize the condensation front associated with the initial air shock; a maximum velocity of 788 m/s was recorded, which decreases to 524 m/s at distance of 0.5 ±0.2 cm, 1.1 ms after the diaphragm rupture. The condensation front preceded the Ar jet front exhausting from the reservoir, by 0.2-0.5 ms. In all experiments particles velocities following the initial

  3. Extracorporeal shock wave treatment for chronic lateral epicondylitis (tennis elbow).

    Science.gov (United States)

    Ho, C

    2007-01-01

    (1) Electrohydraulic, electromagnetic, or piezoelectric devices are used to translate energy into acoustic waves during extracorporeal shock wave treatment (ESWT) for chronic lateral epicondylitis (CLE) of the elbow (elbow tendonitis or tennis elbow). These waves may help to accelerate the healing process via an unknown mechanism. (2) Results from randomized controlled trials have been conflicting. Half of the studies showed statistically significant improvement in pain in the treatment group, and half of the studies had data showing no benefit over placebo for any measured outcomes. (3) Limited evidence shows that ESWT is cheaper than arthroscopic surgery, open surgery, and other conservative therapies, such as steroid infiltrations and physiotherapy, that continue for more than six weeks. (4) The lack of convincing evidence regarding its effectiveness does not support the use of ESWT for CLE.

  4. Non-isentropic layers in matter behind shock and ramp compression waves

    CERN Document Server

    Khishchenko, Konstantin V

    2014-01-01

    According to the ideal fluid dynamics approach, the temperature and entropy values of a medium undergo a jump increase in the shock front as well as on contact interface between different materials after the shock wave propagation, but remain constant behind the shock front out of the contact interface. In the real condensed matter, the shock fronts and transition regions near the interfaces have finite thicknesses; therefore, the temperature field is disturbed around the interfaces. In this work, such disturbances are numerically analyzed for the problems of formation of the steady shock wave at impact and ramp loading of metals, reflection of the steady shock wave from a free surface, and the shock wave passing through the interface between two different materials. Theoretical analysis and computations show that the non-isentropic layers (the high-entropy ones with the increased temperature and the low-entropy ones with the decreased temperature) arise near the interfaces in the above problems of shock and ...

  5. Shock waves in tidally compressed stars by massive black holes

    CERN Document Server

    Brassart, M

    2007-01-01

    We study the case of a solar-type star penetrating deeply within the tidal radius of a massive black hole. We focus on the compression phase leading to a so-called pancake configuration of the star at the instant of maximal compression. The aim is to provide reliable estimates of the thermodynamical quantities involved in the pancake star, and to solve a controversy about whether or not thermonuclear reactions can be triggered in the core of a tidally compressed star. We have set up a one-dimensional hydrodynamical code based on the high-resolution shock-capturing Godunov-type approach in order to study the compression phase undergone by the star in the direction orthogonal to its orbital plane, taking into account the development of shock waves during that phase. We show the existence of two regimes of compression depending on whether shock waves develop after or before the instant of maximal compression. In both cases we confirm high compression and heating factors in the stellar core, able to trigger a the...

  6. Studies of dissipative standing shock waves around black holes

    CERN Document Server

    Das, Santabrata; Mondal, Soumen

    2009-01-01

    We investigate the dynamical structure of advective accretion flow around stationary as well as rotating black holes. For a suitable choice of input parameters, such as, accretion rate ($\\dot {\\cal M}$) and angular momentum ($\\lambda$), global accretion solution may include a shock wave. The post shock flow is located at few tens of Schwarzchild radius and it is generally very hot and dense. This successfully mimics the so called Compton cloud which is believed to be responsible for emitting hard radiations. Due to the radiative loss, a significant energy from the accreting matter is removed and the shock moves forward towards the black hole in order to maintain the pressure balance across it. We identify the effective area of the parameter space ($\\dot {\\cal M} - \\lambda$) which allows accretion flows to have some energy dissipation at the shock $(\\Delta {\\cal E})$. As the dissipation is increased, the parameter space is reduced and finally disappears when the dissipation is reached its critical value. The d...

  7. Wave breaking and shock waves for a periodic shallow water equation.

    Science.gov (United States)

    Escher, Joachim

    2007-09-15

    This paper is devoted to the study of a recently derived periodic shallow water equation. We discuss in detail the blow-up scenario of strong solutions and present several conditions on the initial profile, which ensure the occurrence of wave breaking. We also present a family of global weak solutions, which may be viewed as global periodic shock waves to the equation under discussion.

  8. Reflection of a converging cylindrical shock wave segment by a straight wedge

    Science.gov (United States)

    Gray, B.; Skews, B.

    2017-01-01

    As a converging cylindrical shock wave propagates over a wedge, the shock wave accelerates and the angle between the shock wave and the wedge decreases. This causes the conditions at the reflection point to move from what would be the irregular reflection domain for a straight shock wave into the regular reflection domain. This paper covers a largely qualitative study of the reflection of converging shock wave segments with Mach numbers between 1.2 and 2.1 by wedges inclined at angles between 15° and 60° from experimental and numerical results. The sonic condition conventionally used for predicting the type of reflection of straight shock waves was found to also be suitable for predicting the initial reflection of a curved shock wave. Initially regular reflections persisted until the shock was completely reflected by the wedge, whereas the triple point of initially irregular reflections was observed to return to the wedge surface, forming transitioned regular reflection. After the incident shock wave was completely reflected by the wedge, a shock wave focusing mechanism was observed to amplify the pressure on the surface of the wedge by a factor of up to 100 for low wedge angles.

  9. Modeling shock waves in an ideal gas: combining the Burnett approximation and Holian's conjecture.

    Science.gov (United States)

    He, Yi-Guang; Tang, Xiu-Zhang; Pu, Yi-Kang

    2008-07-01

    We model a shock wave in an ideal gas by combining the Burnett approximation and Holian's conjecture. We use the temperature in the direction of shock propagation rather than the average temperature in the Burnett transport coefficients. The shock wave profiles and shock thickness are compared with other theories. The results are found to agree better with the nonequilibrium molecular dynamics (NEMD) and direct simulation Monte Carlo (DSMC) data than the Burnett equations and the modified Navier-Stokes theory.

  10. Kinematics of ICMEs/shocks: blast wave reconstruction using type II emissions

    CERN Document Server

    Corona-Romero, P; Aguilar-Rodriguez, E; de-la-Luz, V; Mejia-Ambriz, J C

    2015-01-01

    We present a physical methodology to reconstruct the trajectory of interplanetary shocks using type II radio emission data. This technique calculates the shock trajectory assuming that the disturbance propagates as a blast wave in the interplanetary medium. We applied this Blast Wave Reconstruction (BWR) technique to analyze eight fast Earth-directed ICMEs/shocks associated with type II emissions. The technique deduces a shock trajectory that reproduces the type II frequency drifts, and calculates shock onset speed, shock transit time and shock speed at 1~AU. There were good agreements comparing the BWR results with the type II spectra, with data from coronagraph images, {\\it in situ} measurements, and interplanetary scintillation (IPS) observations. Perturbations on the type II data affect the accuracy of the BWR technique. This methodology could be applied to track interplanetary shocks causing TII emissions in real-time, to predict the shock arrival time and shock speed at 1~AU.

  11. Fracture of nanoceramics with porous structure at shock wave loadings

    Science.gov (United States)

    Skripnyak, Vladimir; Skripnyak, Vladimir; Skripnyak, Vladimir

    2012-03-01

    Computer simulation techniques are used to investigate the deformation and damage processes taking place in brittle oxide nanostructured ceramics under intense dynamic loading. The pore structure is shown to substantially affect the size of the fragments and the strength of the ceramics. In porous nanostructured ceramics subjected to shock loading, deformation is localized in mesoscopic bands having characteristic orientations along, across, and at ~ 45° to the direction of propagation of the shock wave front. Clusters of nanopores cause the decreasing of the shear strength of nanostructured ceramics. The localized deformation bands may be transformed into mesoscopic cracks. A method is proposed for a theoretical estimation of the effective elastic moduli of ceramics with pore structure without resorting to well-known hypotheses for the relation between elastic moduli and porosity of the materials.

  12. Resistant tennis elbow: shock-wave therapy versus percutaneous tenotomy.

    Science.gov (United States)

    Radwan, Yasser A; ElSobhi, Gamal; Badawy, Walid S; Reda, Ali; Khalid, Sherif

    2008-10-01

    Fifty-six patients who suffered from chronic persistent tennis elbow of more than six months duration were randomly assigned to two active treatment groups. Group 1 (n = 29) received high-energy extracorporeal shock wave treatment (ESWT; 1,500 shocks) at 18 kV (0.22 mJ/mm(2)) without local anaesthesia; group 2 (n = 27) underwent percutaneous tenotomy of the common extensor origin. Both groups achieved improvement from the base line at three weeks, six weeks, 12 weeks and 12 months post-intervention. The success rate (Roles and Maudsley score: excellent and good) at three months in the ESWT group was 65.5% and in the tenotomy group was 74.1%. ESWT appeared to be a useful noninvasive treatment method that reduced the necessity for surgical procedures.

  13. Investigation of surface acoustic waves in laser shock peened metals

    Institute of Scientific and Technical Information of China (English)

    Ling Yuan; Gang Yan; Zhonghua Shen; Hangwei Xu; Xiaowu Ni; Jian Lu

    2008-01-01

    Laser shock peening is a well-known method for extending the fatigue life of metal components by introducing near-surface compressive residual stress. The surface acoustic waves (SAWs) are dispersive when the near-surface properties of materials are changed. So the near-surface properties (such as the thickness of hardened layers, elastic properties, residual stresses, etc.) can be analyzed by the phase velocity dispersion. To study the propagation of SAWs in metal samples after peening, a more reasonable experimental method of broadband excitation and reception is introduced. The ultrasonic signals are excited by laser and received by polyvinylindene fluoride (PVDF) transducer. The SAW signals in aluminum alloy materials with different impact times by laser shock peening are detected. Signal spectrum and phase velocity dispersion curves of SAWs are analyzed. Moreover, reasons for dispersion are discussed.

  14. Numerical Simulation of Wave Propagation and Phase Transition of Tin under Shock-Wave Loading

    Institute of Scientific and Technical Information of China (English)

    SONG Hai-Feng; LIU Hai-Feng; ZHANG Guang-Cai; ZHAO Yan-Song

    2009-01-01

    We undertake a numerical simulation of shock experiments on tin reported in the literature,by using a multiphase equation of state (MEOS) and a multiphase Steinberg Guinan (MSG) constitutive model for tin in the β,γ and liquid phases.In the MSG model,the Bauschinger effect is considered to better describe the unloading behavior.The phase diagram and Hugoniot of tin are calculated by MEOS,and they agree well with the experimental data.Combined with the MEOS and MSG models,hydrodynamic computer simulations are successful in reproducing the measured velocity profile of the shock wave experiment.Moreover,by analyzing the mass fraction contour as well as stress and temperature profiles of each phase for tin,we further discuss the complex behavior of tin under shock-wave loading.

  15. Shock-wave dynamics during oil-filled transformer explosions

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Utkin, A. V.

    2017-05-01

    This paper presents a numerical and experimental study of the shock-wave processes evolving inside a closed vessel filled with mineral oil. Obtained experimental Hugoniot data for oil are compared with the corresponding data for water. It is found that compression of mineral oil and water can be described by approximately the same Hugoniot over a wide pressure range. Such similarity allows the use of water instead of mineral oil in the transformer explosion experiments and to describe the compression processes in both liquids using similar equations of state. The Kuznetsov equation of state for water is adopted for a numerical study of mineral oil compression. The features of the evolution of shock waves within mineral oil are analyzed using two-dimensional numerical simulations. Numerical results show that different energy sources may cause different scenarios of loading on the shell. The principal point is the phase transition taking place at relatively high temperatures for the case of high-power energy sources. In this case, a vapor-gaseous bubble emerges that qualitatively changes the dynamics of compression waves and the pattern of loads induced on the shell. Taking into account the features of the process together with the concept of water-oil similarity, the present work presents a new approach for experimental modeling of transformer shell destruction using an explosion with given characteristics in a water-filled shell.

  16. Shock-wave dynamics during oil-filled transformer explosions

    Science.gov (United States)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Utkin, A. V.

    2016-08-01

    This paper presents a numerical and experimental study of the shock-wave processes evolving inside a closed vessel filled with mineral oil. Obtained experimental Hugoniot data for oil are compared with the corresponding data for water. It is found that compression of mineral oil and water can be described by approximately the same Hugoniot over a wide pressure range. Such similarity allows the use of water instead of mineral oil in the transformer explosion experiments and to describe the compression processes in both liquids using similar equations of state. The Kuznetsov equation of state for water is adopted for a numerical study of mineral oil compression. The features of the evolution of shock waves within mineral oil are analyzed using two-dimensional numerical simulations. Numerical results show that different energy sources may cause different scenarios of loading on the shell. The principal point is the phase transition taking place at relatively high temperatures for the case of high-power energy sources. In this case, a vapor-gaseous bubble emerges that qualitatively changes the dynamics of compression waves and the pattern of loads induced on the shell. Taking into account the features of the process together with the concept of water-oil similarity, the present work presents a new approach for experimental modeling of transformer shell destruction using an explosion with given characteristics in a water-filled shell.

  17. Linear shock wave therapy in the treatment of erectile dysfunction.

    Science.gov (United States)

    Pelayo-Nieto, M; Linden-Castro, E; Alias-Melgar, A; Espinosa-Pérez Grovas, D; Carreño-de la Rosa, F; Bertrand-Noriega, F; Cortez-Betancourt, R

    2015-09-01

    Linear Shock Wave Therapy (LSWT) is a new noninvasive therapy that uses low-intensity shock waves to induce local angiogenesis promising modality in the treatment of erectile dysfunction (ED). To evaluate the effectiveness of LSWT in men with vasculogenic erectile dysfunction (ED), in a Tertiary Care Center. Included 15 men aged 45-70 years, sexually active with mild and moderate vascular ED evaluated with the International Index of Erectile Function (IIEF). The study was conducted in three stage: screening, treatment and results. Treatment stage: 4 weekly sessions LSWT (RENOVA ®) 5000 waves (.09mJ/mm(2)). Erectile function was assessed with IIEFF-EF, SEP (Sexual Encounter Profile) and GAQ (Global Assessment Questions) at one and six months after treatment. The rate of success was 80% (12/15). Patients with mild ED (6/15) 40% and moderate ED (9/15) 60%. We found a positive association between IIEF-Basal (average 14.23 pts) and IIEF at one month and six months after therapy (19.69 pts) a difference of 5.46 pts. (P<.013). The feasibility and tolerability of this treatment, and rehabilitation potential features, make it this an attractive new treatment option for patients with ED. Copyright © 2014 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Analgesic effect of extracorporeal shock wave therapy versus ultrasound therapy in chronic tennis elbow

    OpenAIRE

    2015-01-01

    [Purpose] This study compared the analgesic effects of extracorporeal shock wave therapy with those of ultrasound therapy in patients with chronic tennis elbow. [Subjects] Fifty patients with tennis elbow were randomized to receive extracorporeal shock wave therapy or ultrasound therapy. [Methods] The extracorporeal shock wave therapy group received 5 treatments once per week. Meanwhile, the ultrasound group received 10 treatments 3 times per week. Pain was assessed using the visual analogue ...

  19. Modeling secondary accidents identified by traffic shock waves.

    Science.gov (United States)

    Junhua, Wang; Boya, Liu; Lanfang, Zhang; Ragland, David R

    2016-02-01

    The high potential for occurrence and the negative consequences of secondary accidents make them an issue of great concern affecting freeway safety. Using accident records from a three-year period together with California interstate freeway loop data, a dynamic method for more accurate classification based on the traffic shock wave detecting method was used to identify secondary accidents. Spatio-temporal gaps between the primary and secondary accident were proven be fit via a mixture of Weibull and normal distribution. A logistic regression model was developed to investigate major factors contributing to secondary accident occurrence. Traffic shock wave speed and volume at the occurrence of a primary accident were explicitly considered in the model, as a secondary accident is defined as an accident that occurs within the spatio-temporal impact scope of the primary accident. Results show that the shock waves originating in the wake of a primary accident have a more significant impact on the likelihood of a secondary accident occurrence than the effects of traffic volume. Primary accidents with long durations can significantly increase the possibility of secondary accidents. Unsafe speed and weather are other factors contributing to secondary crash occurrence. It is strongly suggested that when police or rescue personnel arrive at the scene of an accident, they should not suddenly block, decrease, or unblock the traffic flow, but instead endeavor to control traffic in a smooth and controlled manner. Also it is important to reduce accident processing time to reduce the risk of secondary accident. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. A study on compressive shock wave propagation in metallic foams

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Metallic foam can dissipate a large amount of energy due to its relatively long stress plateau,which makes it widely applicable in the design of structural crashworthiness. However,in some experimental studies,stress enhancement has been observed when the specimens are subjected to intense impact loads,leading to severe damage to the objects being protected. This paper studies this phenomenon on a 2D mass-spring-bar model. With the model,a constitutive relationship of metal foam and corresponding loading and unloading criteria are presented; a nonlinear kinematics equilibrium equation is derived,where an explicit integra-tion algorithm is used to calculate the characteristic of the compressive shock wave propagation within the metallic foam; the effect of heterogeneous distribution of foam microstructures on the shock wave features is also included. The results reveal that under low impact pulses,considerable energy is dissipated during the progressive collapse of foam cells,which then reduces the crush of objects. When the pulse is sufficiently high,on the other hand,stress enhancement may take place,especially in the heterogeneous foams,where high peak stresses usually occur. The characteristics of compressive shock wave propagation in the foam and the magnitude and location of the peak stress produced are strongly dependent on the mechanical properties of the foam material,amplitude and period of the pulse,as well as the homogeneity of the microstructures. This research provides valuable insight into the reliability of the metallic foams used as a protective structure.

  1. The criterion of the existence or inexistence of transverse shock wave at wedge supported oblique detonation wave

    Institute of Scientific and Technical Information of China (English)

    Ai-Feng Wang; Wei Zhao; Zong-Lin Jiang

    2011-01-01

    A simplified theoretic method and numerical simulations were carried out to investigate the characterization of propagation of transverse shock wave at wedge supported oblique detonation wave.After solution validation,a criterlon which is associated with the ratio φ (u2/ucJ) of existence or inexistence of the transverse shock wave at the region of the primary triple was deduced systematically by 38 cases.It is observed that for abrupt oblique shock wave (OSW)/oblique detonation wave (ODW) transition,a transverse shock wave is generated at the region of the primary triple when φ < 1,however,such a transverse shock wave does not take place for the smooth OSW/ODW transition when φ > 1.The parameter φ can be expressed as the Mach number behind the ODW front for stable CJ detonation.When 0.9 < φ < 1.0,the reflected shock wave can pass across the contact discontinuity and interact with transverse waves which are originating from the ODW front.When 0.8 < φ < 0.9,the reflected shock wave can not pass across the contact discontinuity and only reflects at the contact discontinuity.The condition (0.8 < φ < 0.9) agrees well with the ratio (Dave/DcJ) in the critical detonation.

  2. The Boundary Layer Interaction with Shock Wave and Expansion Fan

    Institute of Scientific and Technical Information of China (English)

    MaratA.Goldfeld; RomanV.Nestoulia; 等

    2000-01-01

    The results of experimental investigation of a turbulent boundary layer on compression and expansion surfaces are presented.They include the study of the shock wave and /or expansion fan action upon the boundary layer,boundary layer sepqartion and its relaxation.Complex events of paired interactions and the flow on compression convex-concave surfaces were studied.The posibility and conditions of the boundary layer relaminarization behind the expansion fan and its effect on the relaxation length are presented.Different model configurations for wide range conditions were investigated.Comparison of results for different interactions was carried out.

  3. Radial extracorporeal shock wave therapy for heterotopic ossification

    OpenAIRE

    Ryu, Byung-Ju; Ha, Kang-Wook; Lee, Jin-Young; Kim, Sung-Hwan; Kwak, Ho-Jun; Seol, Pyong-Hwa

    2016-01-01

    [Purpose] To report the effects of radial extracorporeal shock wave therapy (RSWT) on heterotopic ossification (HO). [Subjects and Methods] Two cases of neurogenic HO in the upper extremity were administered RSWT using the MASTER PLUS® MP 2000 (Storz, Tägerwilen, Switzerland) and ultrasonographic guidance. The RSWT protocol consisted of 3,000 pulses at a frequency of 12 Hz during each treatment. The intensity level ranged from 2–5 bars, and it was administered 5 times a week for 4 weeks, a to...

  4. NUMERICAL SIMULATION OF SHOCK WAVE REFRACTION ON INCLINED CONTACT DISCONTINUITY

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2016-05-01

    Full Text Available We consider numerical simulation of shock wave refraction on plane contact discontinuity, separating two gases with different density. Discretization of Euler equations is based on finite volume method and WENO finite difference schemes, implemented on unstructured meshes. Integration over time is performed with the use of the third-order Runge–Kutta stepping procedure. The procedure of identification and classification of gas dynamic discontinuities based on conditions of dynamic consistency and image processing methods is applied to visualize and interpret the results of numerical calculations. The flow structure and its quantitative characteristics are defined. The results of numerical and experimental visualization (shadowgraphs, schlieren images, and interferograms are compared.

  5. Acoustic and Cavitation Fields of Shock Wave Therapy Devices

    Science.gov (United States)

    Chitnis, Parag V.; Cleveland, Robin O.

    2006-05-01

    Extracorporeal shock wave therapy (ESWT) is considered a viable treatment modality for orthopedic ailments. Despite increasing clinical use, the mechanisms by which ESWT devices generate a therapeutic effect are not yet understood. The mechanistic differences in various devices and their efficacies might be dependent on their acoustic and cavitation outputs. We report acoustic and cavitation measurements of a number of different shock wave therapy devices. Two devices were electrohydraulic: one had a large reflector (HMT Ossatron) and the other was a hand-held source (HMT Evotron); the other device was a pneumatically driven device (EMS Swiss DolorClast Vet). Acoustic measurements were made using a fiber-optic probe hydrophone and a PVDF hydrophone. A dual passive cavitation detection system was used to monitor cavitation activity. Qualitative differences between these devices were also highlighted using a high-speed camera. We found that the Ossatron generated focused shock waves with a peak positive pressure around 40 MPa. The Evotron produced peak positive pressure around 20 MPa, however, its acoustic output appeared to be independent of the power setting of the device. The peak positive pressure from the DolorClast was about 5 MPa without a clear shock front. The DolorClast did not generate a focused acoustic field. Shadowgraph images show that the wave propagating from the DolorClast is planar and not focused in the vicinity of the hand-piece. All three devices produced measurable cavitation with a characteristic time (cavitation inception to bubble collapse) that varied between 95 and 209 μs for the Ossatron, between 59 and 283 μs for the Evotron, and between 195 and 431 μs for the DolorClast. The high-speed camera images show that the cavitation activity for the DolorClast is primarily restricted to the contact surface of the hand-piece. These data indicate that the devices studied here vary in acoustic and cavitation output, which may imply that the

  6. CT appearance of renal hemorrhage after extracorporeal shock wave lithotripsy

    Energy Technology Data Exchange (ETDEWEB)

    Kanazawa, Susumu; Araki, Toru; Takamoto, Hitoshi; Hata, Kazuhiro

    1988-07-01

    Computed Tomography (CT) was performed in three patients who were suspicious of renal hemorrhage after extracorporeal shock wave lithotripsy (ESWL). Post-ESWL scans demonstrated subcapsular hematoma in all three cases, and intrarenal hemorrhage in two cases, one of which had fluid collection in the pararenal space and hemorrhage in the posterior pararenal space on CT. Thickening of gerota fascia and bridging septa in the perirenal space was visualized on CT in all of them. CT demonstrated clearly the anatomic distribution and extent of renal hemorrhage, and it is important to comprehend the imaging anatomy of the perirenal area for CT evaluation.

  7. Tracking the density evolution in counter-propagating shock waves using imaging X-ray scattering

    Science.gov (United States)

    Zastrau, U.; Gamboa, E. J.; Kraus, D.; Benage, J. F.; Drake, R. P.; Efthimion, P.; Falk, K.; Falcone, R. W.; Fletcher, L. B.; Galtier, E.; Gauthier, M.; Granados, E.; Hastings, J. B.; Heimann, P.; Hill, K.; Keiter, P. A.; Lu, J.; MacDonald, M. J.; Montgomery, D. S.; Nagler, B.; Pablant, N.; Schropp, A.; Tobias, B.; Gericke, D. O.; Glenzer, S. H.; Lee, H. J.

    2016-07-01

    We present results from time-resolved X-ray imaging and inelastic scattering on collective excitations. These data are then employed to infer the mass density evolution within laser-driven shock waves. In our experiments, thin carbon foils are first strongly compressed and then driven into a dense state by counter-propagating shock waves. The different measurements agree that the graphite sample is about twofold compressed when the shock waves collide, and a sharp increase in forward scattering indicates disassembly of the sample 1 ns thereafter. We can benchmark hydrodynamics simulations of colliding shock waves by the X-ray scattering methods employed.

  8. Tandem shock waves in medicine and biology: a review of potential applications and successes

    Science.gov (United States)

    Lukes, P.; Fernández, F.; Gutiérrez-Aceves, J.; Fernández, E.; Alvarez, U. M.; Sunka, P.; Loske, A. M.

    2016-01-01

    Shock waves have been established as a safe and effective treatment for a wide range of diseases. Research groups worldwide are working on improving shock wave technology and developing new applications of shock waves to medicine and biology. The passage of a shock wave through soft tissue, fluids, and suspensions containing cells may result in acoustic cavitation i.e., the expansion and violent collapse of microbubbles, which generates secondary shock waves and the emission of microjets of fluid. Cavitation has been recognized as a significant phenomenon that produces both desirable and undesirable biomedical effects. Several studies have shown that cavitation can be controlled by emitting two shock waves that can be delayed by tenths or hundreds of microseconds. These dual-pulse pressure pulses, which are known as tandem shock waves, have been shown to enhance in vitro and in vivo urinary stone fragmentation, cause significant cytotoxic effects in tumor cells, delay tumor growth, enhance the bactericidal effect of shock waves and significantly increase the efficiency of genetic transformations in bacteria and fungi. This article provides an overview of the basic physical principles, methodologies, achievements and potential uses of tandem shock waves to improve biomedical applications.

  9. A histomorphometric study of necrotic femoral head in rabbits treated with extracorporeal shock waves

    Science.gov (United States)

    Ma, Huan-Zhi; Zhou, Dong-Sheng; Li, Dong; Zhang, Wei; Zeng, Bing-Fang

    2017-01-01

    [Purpose] This study aimed to determine the effectiveness and mechanisms of extracorporeal shock wave therapy in the treatment of femoral head osteonecrosis. [Subjects and Methods] Histomorphometric analysis of necrotic femoral head in rabbits treated with shock waves was performed. Bilateral osteonecrosis of femoral heads was induced with methylprednisolone and lipopolysaccharide in eight rabbits. The left limb (study side) received shock waves to the femoral head. The right limb (control side) received no shock waves. Biopsies of the femoral heads were performed at 12 weeks after shock wave therapy. [Results] Necrotic femoral heads treated with shock waves, compared with controls, had higher bone volume per tissue volume, trabecular thickness, trabecular number, osteoblast surface/bone surface, osteoid surface/bone surface, osteoid thickness, mineralizing surface/bone surface, mineralizing apposition rate, and bone formation rate. However, trabecular separation was lower in shock wave-treated femoral heads than in controls. Eroded surface/bone surface and osteoclast surface/bone surface did not differ significantly between groups. [Conclusion] The bone mass of necrotic femoral heads treated with shock waves increases. Extracorporeal shock wave may promote bone repair in necrotic femoral heads through the proliferation and activation of osteoblasts. PMID:28210032

  10. Interaction of Shock Waves in Cement Mortar Plate Investigated by the Digital Speckle Correlation Method

    Institute of Scientific and Technical Information of China (English)

    LI Xu-Dong; LIU Kai-Xin; ZHANG Guang-Sheng; WEN Shang-Gang; TAN Fu-Li

    2008-01-01

    @@ Interaction of shock waves in cement mortar plate is studied by digital speckle correlation method and digital high-speed photography technique. When the plates were destroyed by two detonators exploding at the same time, variation of shock wave field is obtained. Experimental results show that the interaction of shock waves will result in a nonlinear huge increase of local normal strain, leading to large deformation and serious destruction. However, the occurrence of this strongly nonlinear phenomenon sensitively depends on the interval between detonators, and it will only appear when the interval is smaller than the diameter of the region where shock waves exist.

  11. Study on the formation mechanism of shock wave in process of coal and gas outburst

    Institute of Scientific and Technical Information of China (English)

    SUN Dong-ling; MIAO Fa-tian; LIANG Yun-pei

    2009-01-01

    According to the research results of motion parameters of coal-gas flow, ana-lyzed the formation mechanism of shock waves at different states of coal-gas flow in the process of coal and gas outburst, and briefly described the two possible cases of outburst shock wave formation and their formation conditions in the process of coal and gas out-burst, and then pointed out that a high degree of under-expanded coal-gas flow was the main reason for the formation of a highly destructive shock wave. The research results improved the shock wave theory in coal and gas outburst.

  12. Characteristics of Plasma Shock Waves Generated in the Pulsed Laser Ablation Process

    Institute of Scientific and Technical Information of China (English)

    李智华; 张端明; 郁伯铭; 关丽

    2002-01-01

    We modify the Sedov theory to describe plasma shock waves generated in a pulsed laser ablating process. We also study the propagation characteristics of plasma shock waves during the preparation process of functional thin films deposited by a pulsed laser. In particular, we discuss in detail the temporal behaviour of energy causing the difference of the propagation characteristics between the plasma shock wave and the ideal shock wave in the point explosion model. Under the same experimental conditions, the theoretical results calculated with our modified Sedov theory are in good agreement with the existing experimental data.

  13. Mechanism of laser-induced plasma shock wave evolution in air

    Institute of Scientific and Technical Information of China (English)

    Zhao Rui; Liang Zhong-Cheng; Han Bing; Zhang Hong-Chao; Xu Rong-Qing; Lu Jian; Ni Xiao-Wu

    2009-01-01

    A theoretical model is proposed to describe the mechanism of laser-induced plasma shock wave evolution in air. To verify the validity of the theoretical model, an optical beam deflection technique is employed to track the plasma shock wave evolution process. The theoretical model and the experimental signals are found to be in good agreement with each other. It is shown that the laser-induced plasma shock wave undergoes formation, increase and decay processes; the increase and the decay processes of the laser-induced plasma shock wave result from the overlapping of the compression wave and the rarefaction wave, respectively. In addition, the laser-induced plasma shock wave speed and pressure distributions, both a function of distance, are presented.

  14. Photoacoustic shock wave emission and cavitation from structured optical fiber tips

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadzadeh, M.; Gonzalez-Avila, S. R.; Ohl, C. D., E-mail: cdohl@ntu.edu.sg [School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371 (Singapore); Wan, Y. C.; Wang, X.; Zheng, H. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore)

    2016-01-11

    Photoacoustic waves generated at the tip of an optical fiber consist of a compressive shock wave followed by tensile diffraction waves. These tensile waves overlap along the fiber axis and form a cloud of cavitation bubbles. We demonstrate that shaping the fiber tip through micromachining alters the number and direction of the emitted waves and cavitation clouds. Shock wave emission and cavitation patterns from five distinctively shaped fiber tips have been studied experimentally and compared to a linear wave propagation model. In particular, multiple shock wave emission and generation of strong tension away from the fiber axis have been realized using modified fiber tips. These altered waveforms may be applied for novel microsurgery protocols, such as fiber-based histotripsy, by utilizing bubble-shock wave interaction.

  15. Coronal Shock Waves, EUV Waves, and Their Relation to CMEs. III. Shock-Associated CME/EUV Wave in an Event with a Two-Component EUV Transient

    CERN Document Server

    Grechnev, V V; Uralov, A M; Chertok, I M; Eselevich, M V; Eselevich, V G; Rudenko, G V; Kubo, Y

    2011-01-01

    On 17 January 2010, STEREO-B observed in extreme ultraviolet (EUV) and white light a large-scale dome-shaped expanding coronal transient with perfectly connected off-limb and on-disk signatures. Veronig et al. (2010, ApJL 716, 57) concluded that the dome was formed by a weak shock wave. We have revealed two EUV components, one of which corresponded to this transient. All of its properties found from EUV, white light, and a metric type II burst match expectations for a freely expanding coronal shock wave including correspondence to the fast-mode speed distribution, while the transient sweeping over the solar surface had a speed typical of EUV waves. The shock wave was presumably excited by an abrupt filament eruption. Both a weak shock approximation and a power-law fit match kinematics of the transient near the Sun. Moreover, the power-law fit matches expansion of the CME leading edge up to 24 solar radii. The second, quasi-stationary EUV component near the dimming was presumably associated with a stretched CM...

  16. Observation of Dispersive Shock Waves, Solitons, and Their Interactions in Viscous Fluid Conduits.

    Science.gov (United States)

    Maiden, Michelle D; Lowman, Nicholas K; Anderson, Dalton V; Schubert, Marika E; Hoefer, Mark A

    2016-04-29

    Dispersive shock waves and solitons are fundamental nonlinear excitations in dispersive media, but dispersive shock wave studies to date have been severely constrained. Here, we report on a novel dispersive hydrodynamic test bed: the effectively frictionless dynamics of interfacial waves between two high viscosity contrast, miscible, low Reynolds number Stokes fluids. This scenario is realized by injecting from below a lighter, viscous fluid into a column filled with high viscosity fluid. The injected fluid forms a deformable pipe whose diameter is proportional to the injection rate, enabling precise control over the generation of symmetric interfacial waves. Buoyancy drives nonlinear interfacial self-steepening, while normal stresses give rise to the dispersion of interfacial waves. Extremely slow mass diffusion and mass conservation imply that the interfacial waves are effectively dissipationless. This enables high fidelity observations of large amplitude dispersive shock waves in this spatially extended system, found to agree quantitatively with a nonlinear wave averaging theory. Furthermore, several highly coherent phenomena are investigated including dispersive shock wave backflow, the refraction or absorption of solitons by dispersive shock waves, and the multiphase merging of two dispersive shock waves. The complex, coherent, nonlinear mixing of dispersive shock waves and solitons observed here are universal features of dissipationless, dispersive hydrodynamic flows.

  17. Supersonic flow. Pt. 5 Shock waves; Fondamenti fisici dei fasci molecolari supersonici. Pt 5 Onde di Shock

    Energy Technology Data Exchange (ETDEWEB)

    Sanna, G.; Tomassetti, G. [L`Aquila Univ. (Italy). Dipt. di Fisica

    1998-02-01

    The discontinuities in the flow fields (both tangential and shocks) are considered and the equations for the quantities conserved across them are written. The post-shock flow variables are expressed by the Mach number of the incident supersonic flow and its deflection angle operated by rigid wall. Normal and oblique shocks are considered and graphs and polar diagrams are introduced. Then the reflections of a shock wave operated by a rigid wall and by the boundary between a jet and a stagnating gas are analyzed. Finally, the interactions between two distinct shock waves are considered. [Italiano] Vengono considerate le discontinuita` (tangenziali e shocks) nei campi di flusso e sono scritte le equazioni per le quantita` che si conservano attraverso di esse. Le variabili del flusso oltre lo shock sono espresse in funzione del numero di Mach del flusso supersonico incidente e dell`angolo di deflessione di questo operato da una parete rigida. I casi di shock normale, obliquo e distaccato sono considerati e sono introdotti grafici vari e rappresentazioni polari. Sono quindi considerate le riflessioni di un fronte di shock da una parete rigida e dalla frontiera tra un gas in moto ed uno stagnante. Sono infine considerate le diverse interazioni tra due shock distinti.

  18. Wave propagation and shock formation in different magnetic structures

    CERN Document Server

    Centeno, Rebecca; Bueno, Javier Trujillo

    2008-01-01

    Velocity oscillations "measured" simultaneously at the photosphere and the chromosphere -from time series of spectropolarimetric data in the 10830 A region- of different solar magnetic features allow us to study the properties of wave propagation as a function of the magnetic flux of the structure (i.e. two different-sized sunspots, a tiny pore and a facular region). While photospheric oscillations have similar characteristics everywhere, oscillations measured at chromospheric heights show different amplitudes, frequencies and stages of shock development depending on the observed magnetic feature. The analysis of the power and the phase spectra, together with simple theoretical modeling, lead to a series of results concerning wave propagation within the range of heights of this study. We find that, while the atmospheric cut-off frequency and the propagation properties of the different oscillating modes depend on the magnetic feature, in all the cases the power that reaches the high chromosphere above the atmo...

  19. Focused and Radial Shock Wave Therapy in the Treatment of Tennis Elbow: A Pilot Randomised Controlled Study

    OpenAIRE

    2015-01-01

    The purpose of this article was to evaluate and compare the efficacy of radial and focused shock wave therapies applied to treat tennis elbow. Patients with tennis elbow were randomized into two comparative groups: focused shock wave therapy (FSWT; n=25) and radial shock wave therapy (RSWT; n=25). Subjects in the FSWT and RSWT groups were applied with a focused shock wave (3 sessions, 2000 shocks, 4 Hz, 0.2 mJ/mm2) and a radial shock wave (3 sessions, 2000 + 2000 shocks, 8 Hz, 2.5 bar), respe...

  20. A $55 Shock Tube for Simulated Blast Waves

    CERN Document Server

    Courtney, Elijah; Courtney, Michael

    2015-01-01

    Shock tubes are commonly employed to test candidate armor materials, validate numerical models, and conduct simulated blast experiments in animal models. As DoD interests desire to field wearable sensors as blast dosimeters, shock tubes may also serve for calibration and testing of these devices. The high blast pressures needed for experimental testing of candidate armors are unnecessary to test these sensors. An inexpensive, efficient, and easily available way of testing these pressure sensors is desirable. It is known that releasing compressed gas suddenly can create a repeatable shock front, and the pressures can be finely tuned by changing the pressure to which the gas is compressed. A Crosman 0.177 caliber air pistol was used (without loading any pellets) to compress and release air in one end of a 24 inch long 3/4 inch diameter standard pipe nipple to simulate a blast wave at the other end of the tube. A variable number of pumps were used to vary the peak blast pressure. As expected, the trials where 10...

  1. Experimental and theoretical investigations on shock wave induced phase transitions

    Science.gov (United States)

    Gupta, Satish C.; Sikka, S. K.

    2001-06-01

    Shock wave loading of a material can cause variety of phase transitions, like polymorphism, amorphization, metallization and molecular dissociations. As the shocked state lasts only for a very short duration (about a few microseconds or less), in-situ microscopic measurements are very difficult. Although such studies are beginning to be possible, most of the shock-induced phase transitions are detected using macroscopic measurements. The microscopic nature of the transition is then inferred from comparison with static pressure data or interpreted by theoretical methods. For irreversible phase transitions, microscopic measurements on recovered samples, together with orientation relations determined from selected area electron diffraction and examination of the morphology of growth of the new phase can provide insight into mechanism of phase transitions. On theoretical side, the current ab initio band structure techniques based on density functional formalism provide capability for accurate computation of the small energy differences (a few mRy or smaller) between different plausible structures. Total energy calculation along the path of a phase transition can furnish estimates of activation barrier, which has implications for understanding kinetics of phase transitions. Molecular dynamics calculations, where the new structure evolves naturally, are becoming increasingly popular especially for understanding crystal to amorphous phase transitions. Illustrations from work at our laboratory will be presented.

  2. Numerical and Experimental Study on Contact Face and Shock Wave Motion in the Receiving Tube of Gas Wave Refrigerator

    Institute of Scientific and Technical Information of China (English)

    Dapeng HU; Shengtao CHEN; Hu LIU; Zuzhi CHEN; Che ZHU

    2006-01-01

    The contact face and shock wave motion in an open ends receiving tube of gas wave refrigerator are investigated numerically and experimentally.The results show that,velocity of the contact face rises rapidly as gas is injected into the receiving tube,and drops sharply after a steady propagation.However,velocity of the shock wave in the tube is almost linear.With increasing of inlet pressure,velocity of the shock wave and steady velocity of contact face also increase.In addition,time and distance of contact face propagation in the receiving tube become longer.

  3. Shock Wave Observation in Narrow Tubes for a Parametric Study on Micro Wave Rotor Design

    Institute of Scientific and Technical Information of China (English)

    Koji Okamoto; Mikiya Araki

    2008-01-01

    Wave rotor is expected to improve the performance of micro gas turbines drastically. In the wave rotor design, the rotor speed is determined principally by the tube length. Therefore, a longer tube is preferable for miniaturized wave rotors to avoid the difficulty in bearings and lubrication system, while it may yield thicker wall boundary layer, shock wave dissipation and so on. In the present study, an experimental apparatus was built to visualize the wave rotor internal flow dynamics in a narrow tube by schlieren method and Laser Doppler Anemometry. In addition, different lengths of the tube were adopted and compared to investigate the effect of wall friction. Finally, 2D numerical simulation was performed and the results were compared with those of experiments.

  4. Wireless device for activation of an underground shock wave absorber

    Science.gov (United States)

    Chikhradze, M.; Akhvlediani, I.; Bochorishvili, N.; Mataradze, E.

    2011-10-01

    The paper describes the mechanism and design of the wireless device for activation of energy absorber for localization of blast energy in underground openings. The statistics shows that the greatest share of accidents with fatal results associate with explosions in coal mines due to aero-methane and/or air-coal media explosion. The other significant problem is terrorist or accidental explosions in underground structures. At present there are different protective systems to reduce the blast energy. One of the main parts of protective Systems is blast Identification and Registration Module. The works conducted at G. Tsulukidze Mining Institute of Georgia enabled to construct the wireless system of explosion detection and mitigation of shock waves. The system is based on the constant control on overpressure. The experimental research continues to fulfill the system based on both threats, on the constant control on overpressure and flame parameters, especially in underground structures and coal mines. Reaching the threshold value of any of those parameters, the system immediately starts the activation. The absorber contains a pyrotechnic device ensuring the discharge of dispersed water. The operational parameters of wireless device and activation mechanisms of pyrotechnic element of shock wave absorber are discussed in the paper.

  5. Extracorporeal shock-wave lithotripsy of bile duct stones

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Tae; Kim, Myung Joon; Yoo, Hyung Sik; Suh, Jung Ho; Lee, Moo Sang; Jo, Jang Hwan; Kim, Byung Ro [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1989-12-15

    During the past one and half year, we performed ESWL therapy in 13 patients with common bile duct and intrahepatic duct stones, applying Lithostar-R (Siemens co. West Germany) and analyzed their results. In 13 patients, 9 residual common bile duct stones and 7 intrahepatic duct stones were selected postoperatively. The size of stones were ranged from 0.7 cm to 3.5 cm in diameter. 2 stones were multiple and the remained 14 were single in number. The visualization of stones were done with fluoroscopy after the injection of contrast media via cholangiographic T-tube or ERCP. ESWL were applied continuously until stone disintegration was visible, or upto maximum number of 3500 discharge of shock wave. If not disintegrated upto 3500, patients were underwent second or third lithotripsy session with interval of one week. Our results showed that among 9 common bile duct stones, 4 were completely disintegrated and passed out spontaneously, but 3 partially fragmented and removed by the additional procedure. 2 were failed. Among 7 intrahepatic stones, 3 completely and 2 partially were succeeded. One stone partially fragmented were retained without removal and other one were failed. Skin petechia in all patients were revealed on the entry port of shock wave, but no serous complication was not occurred.

  6. Detecting cavitation in vivo from shock-wave therapy devices

    Science.gov (United States)

    Matula, Thomas J.; Yu, Jinfei; Bailey, Michael R.

    2005-04-01

    Extracorporeal shock-wave therapy (ESWT) has been used as a treatment for plantar faciitis, lateral epicondylitis, shoulder tendonitis, non-unions, and other indications where conservative treatments have been unsuccessful. However, in many areas, the efficacy of SW treatment has not been well established, and the mechanism of action, particularly the role of cavitation, is not well understood. Research indicates cavitation plays an important role in other ultrasound therapies, such as lithotripsy and focused ultrasound surgery, and in some instances, cavitation has been used as a means to monitor or detect a biological effect. Although ESWT can generate cavitation easily in vitro, it is unknown whether or not cavitation is a significant factor in vivo. The purpose of this investigation is to use diagnostic ultrasound to detect and monitor cavitation generated by ESWT devices in vivo. Diagnostic images are collected at various times during and after treatment. The images are then post-processed with image-processing algorithms to enhance the contrast between bubbles and surrounding tissue. The ultimate goal of this research is to utilize cavitation as a means for optimizing shock wave parameters such as amplitude and pulse repetition frequency. [Work supported by APL internal funds and NIH DK43881 and DK55674.

  7. Pressure Distribution for Piezoelectric Extracorporeal Shock Wave Lithotripsy

    Science.gov (United States)

    Yanagida, Yuji; Iwama, Nobuyuki; Okazaki, Kiyoshi

    1993-05-01

    The objective of this study is to develop a safer and more effective extracorporeal shock wave lithotripter. The first stage of the study shows the sound pressure field of the shock wave made by an ECHOLITH ESL-500A. The sound pressure distribution is in a ring configuration on a 60 mm plane in front of the focal plane. As the plane approaches the focal plane, the sound pressure relatively increases at the cross point with the axis of the transducer and decreases at the ring. The focal zone is 2.5 mm × 16.1 mm at 60 V driving voltage and 1.8 mm × 14.2 mm at “INTENSITY 2.” In the next stage we propose a method for changing the field by electronic driving control of each piezoceramic element for effective therapy. The focal zone can be changed from 3.1 mm × 19.1 mm to 3.9 mm × 32.4 mm at 60 V driving voltage with this method. These focal zones are calculated by means of computer simulation.

  8. Shock-Wave Acceleration of Protons on OMEGA EP

    Science.gov (United States)

    Haberberger, D.; Froula, D. H.; Pak, A.; Link, A.; Patel, P.; Fiuza, F.; Tochitsky, S.; Joshi, C.

    2016-10-01

    The creation of an electrostatic shock wave and ensuing ion acceleration is studied on the OMEGA EP Laser System at the Laboratory for Laser Energetics. Previous work using a 10- μm CO2 laser in a H2 gas jet shows promising results for obtaining narrow spectral features in the accelerated proton spectra. Scaling the shock-wave acceleration mechanism to the 1- μm-wavelength drive laser makes it possible to use petawatt-scale laser systems such as OMEGA-EP, but involves tailoring of the plasma profile. To accomplish the necessitated sharp rise to near-critical plasma density and a long exponential fall, an 1- μm-thick CH foil is illuminated on the back side by thermal x rays produced from an irradiated gold foil. The plasma density is measured using the fourth-harmonic probe system, the accelerating fields are probed using an orthogonal proton source, and the accelerated protons and ions are detected with a Thomson parabola. These results will be presented and compared with particle-in-cell simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and LLNL's Laboratory Directed Research and Development program under project 15-LW-095.

  9. MEASUREMENTS OF SHOCK WAVE FORCE IN SHOCK TUBE WITH INDIRECT METHODS

    Directory of Open Access Journals (Sweden)

    Mario Dobrilović

    2005-12-01

    Full Text Available Tests have been conducted at the “Laboratory for testing of civil explosives, detonators, electrical detonators and pyrotechnical materials”, Department for mining and geotechnics of the Faculty of mining, geology and petroleum engineering, University of Zagreb with the purpose of designing a detonator that would unite advantages of a non-electric system and the precision in regulation of time delay in electronic initiation system. Sum of energy released by the wave force in shock tube is a pre-condition for operation of the new detonator, and measurement of wave force is the first step in determining the sum of energy. The sum of energy is measured indirectly, based on two principles: movement sensors and strain.

  10. A Study of the Weak Shock Wave Propagating over a Porous Wall/Cavity System

    Institute of Scientific and Technical Information of China (English)

    H.D.KIM; S.J.JUNG; T.AOKI; T.SETOGUCHI

    2005-01-01

    The present computational study addresses the attenuation of the shock wave propagating in a duct, using a porous wall/cavity system. In the present study, a weak shock wave propagating over the porous wall/cavity system is investigated with computational fluid dynamics. A total variation diminishing scheme is employed to solve the unsteady, two-dimensional, compressible, Navier-Stokes equations. The Mach number of an initial shock wave is changed in the range from 1.02 to 1.12. Several different types of porous wall/cavity systems are tested to investigate the passive control effects. The results show that wall pressure strongly fluctuates due to diffraction and reflection processes of the shock waves behind the incident shock wave. From the results, it is understood that for effective alleviation of tunnel impulse waves, the length of the perforated region should be sufficiently long.

  11. Rigid polyurethane foam as an efficient material for shock wave attenuation

    Science.gov (United States)

    Komissarov, P. V.; Borisov, A. A.; Sokolov, G. N.; Lavrov, V. V.

    2016-09-01

    A new method for reducing parameters of blast waves generated by explosions of HE charges on ground is presented. Most of the traditional techniques reduce the wave parameters at a certain distance from the charge, i.e. as a matter of fact the damping device interacts with a completely formed shock wave. The proposed approach is to use rigid polyurethane foam coating immediately the explosive charge. A distributed structure of such a foam block that provides most efficient shock wave attenuation is suggested. Results of experimental shock wave investigations recorded in tests in which HE charges have been exploded with damping devices and without it are compared.

  12. Velocity Measurement of Induced Flow by a Laser Focusing Shock Wave

    Institute of Scientific and Technical Information of China (English)

    Hiroyuki HIRAHARA; Masaru FUJINAMI; Masaaki KAWAHASHI

    2006-01-01

    The objective of this study is to apply the shock wave for control in a micro channel. The shock wave was generated by a laser focusing of pulsed laser beam in the channel. Using a pulse laser to generate a shock wave,a non-stationary flow was induced in the small space between the parallel plates. The spherical and cylindrical shock propagations were observed with schlieren method. The shock Mach number decreases with time and approaches to unity. As reported in the previous investigations, the shock speed was attenuated in a short distance and time. In the present experiment, It was not found a remarkable difference in the shock speed between the spherical and cylindrical shock experiments. Subsequently, the flow induced by the cylindrical shock wave was studied using PIV technique. A smoke tracer was used in the experiment and its velocity was measured within 100 μs. A numerical simulation was carried out to investigate the momentum relaxation between the gas and smoke particle. A suitable shock initiation model was introduced in the simulation. The experimental results show that a wide acceleration and deceleration zone exist behind the shock wave. Also,the relaxation distance in the experimental data is much longer than that in numerical simulation.

  13. Dust acoustic solitary and shock waves in strongly coupled dusty plasmas with nonthermal ions

    Indian Academy of Sciences (India)

    Hamid Reza Pakzad; Kurosh Javidan

    2009-11-01

    The Korteweg–de Vries–Burgers (KdV–Burgers) equation and modified Korteweg–de Vries–Burgers equation are derived in strongly coupled dusty plasmas containing nonthermal ions and Boltzmann distributed electrons. It is found that solitary waves and shock waves can be produced in this medium. The effects of important parameters such as ion nonthermal parameter, temperature, density and velocity on the properties of shock waves and solitary waves are discussed.

  14. A Bicharacteristic Scheme for the Numerical Computation of Two-Dimensional Converging Shock Waves

    CERN Document Server

    Meier, U E; Meier, Uwe E.; Demmig, Frank

    1997-01-01

    A 2d unsteady bicharacteristic scheme with shock fitting is presented and its characteristic step, shock point step and boundary step are described. The bicharacteristic scheme is compared with an UNO scheme and the Moretti scheme. Its capabilities are illustrated by computing a converging, deformed shock wave.

  15. Shock wave configurations and reflection hysteresis outside a planar Laval nozzle

    Institute of Scientific and Technical Information of China (English)

    Wang Dan; Yu Yong

    2015-01-01

    When the pressure ratio increases from the perfectly expanded condition to the third lim-ited condition in which a normal shock is located on the exit plane, shock wave configurations out-side the nozzle can be further assorted as no shock wave on the perfectly expanded condition, weak oblique shock reflection in the regular reflection (RR) pressure ratio condition, shock reflection hys-teresis in the dual-solution domain of pressure ratio condition, Mach disk configurations in the Mach reflection (MR) pressure ratio condition, the strong oblique shock wave configurations in the corresponding condition, and a normal shock forms on the exit plane in the third limited con-dition. Every critical pressure ratio, especially under regular reflection and Mach reflection pressure ratio conditions, is deduced in the paper according to shock wave reflection theory. A hysteresis phenomenon is also theoretically possible in the dual-solution domain. For a planar Laval nozzle with the cross-section area ratio being 5, different critical pressure ratios are counted in these con-ditions, and numerical simulations are made to demonstrate these various shock wave configura-tions outside the nozzle. Theoretical analysis and numerical simulations are made to get a more detailed understanding about the shock wave structures outside a Laval nozzle and the RRMMR transition in the dual-solution domain.

  16. The propagation and growth of whistler mode waves generated by electron beams in earth's bow shock

    Science.gov (United States)

    Tokar, R. L.; Gurnett, D. A.

    1985-01-01

    In this study, the propagation and growth of whistler mode waves generated by electron beams within earth's bow shock is investigated using a planar model for the bow shock and a model electron distribution function. Within the shock, the model electron distribution function possesses a field-aligned T greater than T beam that is directed toward the magnetosheath. Waves with frequencies between about 1 and 100 Hz with a wide range of wave normal angles are generated by the beam via Landau and anomalous cyclotron resonances. However, because the growth rate is small and because the wave packets traverse the shock quickly, these waves do not attain large amplitudes. Waves with frequencies between about 30 and 150 Hz with a wide range of wave normal angles are generated by the beam via the normal cyclotron resonance. The ray paths for most of these waves are directed toward the solar wind although some wave packets, due to plasma convection travel transverse to the shock normal. These wave packets grow to large amplitudes because they spend a long time in the growth region. The results suggest that whistler mode noise within the shock should increase in amplitude with increasing upstream theta sub Bn. The study provides an explanation for the origin of much of the whistler mode turbulence observed at the bow shock.

  17. Electron acceleration to relativistic energies at a strong quasi-parallel shock wave

    CERN Document Server

    Masters, A; Fujimoto, M; Schwartz, S J; Sergis, N; Thomsen, M F; Retinò, A; Hasegawa, H; Lewis, G R; Coates, A J; Canu, P; Dougherty, M K

    2013-01-01

    Electrons can be accelerated to ultrarelativistic energies at strong (high-Mach number) collisionless shock waves that form when stellar debris rapidly expands after a supernova. Collisionless shock waves also form in the flow of particles from the Sun (the solar wind), and extensive spacecraft observations have established that electron acceleration at these shocks is effectively absent whenever the upstream magnetic field is roughly parallel to the shock surface normal (quasi-parallel conditions). However, it is unclear whether this magnetic dependence of electron acceleration also applies to the far stronger shocks around young supernova remnants, where local magnetic conditions are poorly understood. Here we present Cassini spacecraft observations of an unusually strong solar system shock wave (Saturn's bow shock) where significant local electron acceleration has been confirmed under quasi-parallel magnetic conditions for the first time, contradicting the established magnetic dependence of electron accele...

  18. Inlet boundary conditions for shock wave propagation problems in air ducts

    Science.gov (United States)

    Fashbaugh, R. H.

    1992-03-01

    Shock waves propagating into air ducting systems are numerically studied using data from Kriebel (1972). Small-scale junctions mounted in shock tubes with an incident shock wave are considered. The stagnation pressure ratio through a duct inlet is evaluated for various junction types. The logarithm of this ratio varies linearly with the Mach number of the flow behind the incident shock wave. The static pressure inside the inlet is established using experimental data with given Mach numbers of the incident and inlet flows. A constant stagnation enthalpy through the inlet junction is assumed to establish inflow to the duct.

  19. Time fractional effect on ion acoustic shock waves in ion-pair plasma

    Energy Technology Data Exchange (ETDEWEB)

    Abdelwahed, H. G., E-mail: hgomaa-eg@hotmail.com [Prince Sattam Bin Abdulaziz University, College of Science and Humanitarian Studies, Physics Department (Saudi Arabia); El-Shewy, E. K.; Mahmoud, A. A. [Faculty of Science, Mansoura University, Theoretical Physics Group, Physics Department (Egypt)

    2016-06-15

    The nonlinear properties of ion acoustic shock waves are studied. The Burgers equation is derived and converted into the time fractional Burgers equation by Agrawal’s method. Using the Adomian decomposition method, shock wave solutions of the time fractional Burgers equation are constructed. The effect of the time fractional parameter on the shock wave properties in ion-pair plasma is investigated. The results obtained may be important in investigating the broadband electrostatic shock noise in D- and F-regions of Earth’s ionosphere.

  20. Fibre-optical techniques for measuring various properties of shock waves

    NARCIS (Netherlands)

    Prinse, W.C.; Esveld, R.J. van; Oostdam, R. van; Rooijen, M. van; Bouma, R.H.B.

    1999-01-01

    For the past years we have developed several optical techniques to measure properties of shock waves. The fibre optic probe (FOP) is developed to measure the shock-wave velocity and/or the detonation velocity inside an explosive. The space resolution can be as small as 0.5 mm. Single fibres are used

  1. Development of fiber optic sensors at TNO for explosion and shock wave measurements

    NARCIS (Netherlands)

    Cheng, L.K.; Smorenburg, C.; Bree, J.L.M.J. van; Bouma, R.H.B.; Meer, B.J. van der; Prinse, W.C.; Scholtes, J.H.G.

    2000-01-01

    Fiber Optic sensors are found to be very suitable for explosion and shock wave measurements because they are immune to Electromagnetic Interference (EMI). In the past few years, TNO has developed a number of sensor systems for explosion and shock wave measurements in which the optical fiber is a vit

  2. Detachment and sonoporation of adherent HeLa-cells by shock wave-induced cavitation

    NARCIS (Netherlands)

    Ohl, Claus-Dieter; Wolfrum, Bernhard

    2003-01-01

    The interaction of lithotripter-generated shock waves with adherent cells is investigated using high-speed optical techniques. We show that shock waves permeabilize adherent cells in vitro through the action of cavitation bubbles. The bubbles are formed in the trailing tensile pulse of a lithotripte

  3. In vivo effects of focused shock waves on tumor tissue visualized by fluorescence staining techniques.

    Science.gov (United States)

    Lukes, Petr; Zeman, Jan; Horak, Vratislav; Hoffer, Petr; Pouckova, Pavla; Holubova, Monika; Hosseini, S Hamid R; Akiyama, Hidenori; Sunka, Pavel; Benes, Jiri

    2015-06-01

    Shock waves can cause significant cytotoxic effects in tumor cells and tissues both in vitro and in vivo. However, understanding the mechanisms of shock wave interaction with tissues is limited. We have studied in vivo effects of focused shock waves induced in the syngeneic sarcoma tumor model using the TUNEL assay, immunohistochemical detection of caspase-3 and hematoxylin-eosin staining. Shock waves were produced by a multichannel pulsed-electrohydraulic discharge generator with a cylindrical ceramic-coated electrode. In tumors treated with shock waves, a large area of damaged tissue was detected which was clearly differentiated from intact tissue. Localization and a cone-shaped region of tissue damage visualized by TUNEL reaction apparently correlated with the conical shape and direction of shock wave propagation determined by high-speed shadowgraphy. A strong TUNEL reaction of nuclei and nucleus fragments in tissue exposed to shock waves suggested apoptosis in this destroyed tumor area. However, specificity of the TUNEL technique to apoptotic cells is ambiguous and other apoptotic markers (caspase-3) that we used in our study did not confirmed this observation. Thus, the generated fragments of nuclei gave rise to a false TUNEL reaction not associated with apoptosis. Mechanical stress from high overpressure shock wave was likely the dominant pathway of tumor damage.

  4. A New Physical Metallurgy Phenomenon-the Shock Wave Nanocrystallization of Amorphous Alloys

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Some results of amorphous alloy nanocrystallization by shock wave are presented. Compared with the well knownannealing crystallization, these results seem novel and are very difficult to be explained by the diffusion theory, such asnucleation and growth mechanism in the solid state phase transitions. The shock wave crystallization of amorphousalloy is a new metallurgical phenomenon with possibilities for improving the crystallization theory in physics.

  5. Development of fiber optic sensors at TNO for explosion and shock wave measurements

    NARCIS (Netherlands)

    Cheng, L.K.; Smorenburg, C.; Bree, J.L.M.J. van; Bouma, R.H.B.; Meer, B.J. van der; Prinse, W.C.; Scholtes, J.H.G.

    2000-01-01

    Fiber Optic sensors are found to be very suitable for explosion and shock wave measurements because they are immune to Electromagnetic Interference (EMI). In the past few years, TNO has developed a number of sensor systems for explosion and shock wave measurements in which the optical fiber is a vit

  6. Numerical Simulation and Experiment for Underwater Shock Wave in Newly Designed Pressure Vessel

    Directory of Open Access Journals (Sweden)

    M Shibuta

    2016-09-01

    Full Text Available Modern eating habits depend in large part on the development of food processing technology. Thermal treatments are often performed in the conventional food processing, but it can cause discoloration and loss of nutrients of the food by thermal processing or treatment. On the other hand, food processing using an underwater shock wave has little influence of heat and its processing time is very short, preventing the loss of nutrients. In this research optical observation experiment and the numerical simulation were performed, in order to understand and control the behavior of the underwater shock wave in the development of the processing container using an underwater shock wave for the factory and home. In this experiment a rectangular container was used to observe the behavior of the underwater shock wave. In the experiment, the shock wave was generated by using explosive on the shock wave generation side. The shock wave, which passed through the phosphor bronze and propagated from the aluminum sidewall, was observed on the processing container side. Numerical simulation of an analogous experimental model was investigated, where LS-DYNA software was used for the numerical simulation. The comparative study of the experiment and the numerical simulation was investigated. The behavior of a precursor shock wave from the device wall was able to be clarified. This result is used for development of the device in numerical simulation.

  7. Experimental Generation of Riemann Waves in Optics: A Route to Shock Wave Control

    Science.gov (United States)

    Wetzel, Benjamin; Bongiovanni, Domenico; Kues, Michael; Hu, Yi; Chen, Zhigang; Trillo, Stefano; Dudley, John M.; Wabnitz, Stefano; Morandotti, Roberto

    2016-08-01

    We report the first observation of Riemann (simple) waves, which play a crucial role for understanding the dynamics of any shock-bearing system. This was achieved by properly tailoring the phase of an ultrashort light pulse injected into a highly nonlinear fiber. Optical Riemann waves are found to evolve in excellent quantitative agreement with the remarkably simple inviscid Burgers equation, whose applicability in physical systems is often challenged by viscous or dissipative effects. Our method allows us to further demonstrate a viable novel route to efficiently control the shock formation by the proper shaping of a laser pulse phase. Our results pave the way towards the experimental study, in a convenient benchtop setup, of complex physical phenomena otherwise difficult to access.

  8. Experimental Generation of Riemann Waves in Optics: A Route to Shock Wave Control.

    Science.gov (United States)

    Wetzel, Benjamin; Bongiovanni, Domenico; Kues, Michael; Hu, Yi; Chen, Zhigang; Trillo, Stefano; Dudley, John M; Wabnitz, Stefano; Morandotti, Roberto

    2016-08-12

    We report the first observation of Riemann (simple) waves, which play a crucial role for understanding the dynamics of any shock-bearing system. This was achieved by properly tailoring the phase of an ultrashort light pulse injected into a highly nonlinear fiber. Optical Riemann waves are found to evolve in excellent quantitative agreement with the remarkably simple inviscid Burgers equation, whose applicability in physical systems is often challenged by viscous or dissipative effects. Our method allows us to further demonstrate a viable novel route to efficiently control the shock formation by the proper shaping of a laser pulse phase. Our results pave the way towards the experimental study, in a convenient benchtop setup, of complex physical phenomena otherwise difficult to access.

  9. TRENDS IN THE DEVELOPMENT OF DETONATION ENGINES FOR HIGH-SPEED AEROSPACE AIRCRAFTS AND THE PROBLEM OF TRIPLE CONFIGURATIONS OF SHOCK WAVES. Part II - Research of counterpropagating shock waves and triple shock wave configurations

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2016-03-01

    Full Text Available The paper deals with current issues of the interference theory development of gas-dynamic discontinuities as applied to a problem of propulsion refinement for the air-spacecrafts, designed for hypersonic flight speeds. In the first part of the review we have presented the history of detonation study and different concepts of detonation engines, as well as air intakes designed for hypersonic flight speeds. The second part provides an overview of works on the interference theory development for gas-dynamic discontinuities. We report about classification of the gas-dynamic discontinuities, shock wave propagation, shock-wave structures and triple configurations of shock waves. We have shown that many of these processes are accompanied by a hysteresis phenomenon, there are areas of ambiguity; therefore, in the design of engines and air intakes optimal shock-wave structures should be provided and their sustainability should be ensured. Much attention has recently been given to the use of the air intakes in the shock-wave structures with the rereflection of shock waves and the interference of shock waves in the opposite directions. This review provides increased focus on it, contains references to landmark works, the last calculated and experimental results. Unfortunately, foreign surveys missed many landmark works of the Soviet and Russian researchers, as they were not published in English. At the same time, it was the Soviet school of gas dynamics that has formulated the interference theory of gas-dynamic discontinuities in its present form. To fill this gap is one of this review scopes. The review may be recommended for professionals, engineers and scientists working in the field of aerospace engineering.

  10. Stress Waves in Composite Laminates Excited by Transverse Plane Shock Waves

    Directory of Open Access Journals (Sweden)

    G.R. Liu

    1996-01-01

    Full Text Available A simple 1-dimensional model is presented to investigate elastic stress waves in composite laminates excited by underwater explosion shocks. The focus is on the elastic dynamic stress fields in the composite laminate immediately after the action of the shock wave. In this model, the interaction between the laminate and the water is taken into account, and the effects of the laminate-water interaction on the stress wave fields in the laminate are investigated. In the formulation of the model, wave fields in the laminate and the water are the first obtained in the frequency domain and then transferred into the time domain using the Fourier transform techniques. A quadrature technique is used to deal with the Fourier transform integrals in which the integrands have very sharp peaks on the integral axis. Numerical examples for stress waves in a steel plate and a glass reinforced plastic sandwich laminate are presented. The technique and the results presented in this article may be used in the design of ship hull structures subjected to underwater explosions.

  11. Prediction of Shock Wave Structure in Weakly Ionized Gas Flow by Solving MGD Equation

    Science.gov (United States)

    Deng, Z. T.; Oviedo-Rojas, Ruben; Chow, Alan; Litchford, Ron J.; Cook, Stephen (Technical Monitor)

    2002-01-01

    This paper reports the recent research results of shockwave structure predictions using a new developed code. The modified Rankine-Hugoniot relations across a standing normal shock wave are discussed and adopted to obtain jump conditions. Coupling a electrostatic body force to the Burnett equations, the weakly ionized flow field across the shock wave was solved. Results indicated that the Modified Rankine-Hugoniot equations for shock wave are valid for a wide range of ionization fraction. However, this model breaks down with small free stream Mach number and with large ionization fraction. The jump conditions also depend on the value of free stream pressure, temperature and density. The computed shock wave structure with ionization provides results, which indicated that shock wave strength may be reduced by existence of weakly ionized gas.

  12. Analgesic effect of extracorporeal shock wave therapy versus ultrasound therapy in chronic tennis elbow.

    Science.gov (United States)

    Lizis, Paweł

    2015-08-01

    [Purpose] This study compared the analgesic effects of extracorporeal shock wave therapy with those of ultrasound therapy in patients with chronic tennis elbow. [Subjects] Fifty patients with tennis elbow were randomized to receive extracorporeal shock wave therapy or ultrasound therapy. [Methods] The extracorporeal shock wave therapy group received 5 treatments once per week. Meanwhile, the ultrasound group received 10 treatments 3 times per week. Pain was assessed using the visual analogue scale during grip strength evaluation, palpation of the lateral epicondyle, Thomsen test, and chair test. Resting pain was also recorded. The scores were recorded and compared within and between groups pre-treatment, immediately post-treatment, and 3 months post-treatment. [Results] Intra- and intergroup comparisons immediately and 3 months post-treatment showed extracorporeal shock wave therapy decreased pain to a significantly greater extent than ultrasound therapy. [Conclusion] Extracorporeal shock wave therapy can significantly reduce pain in patients with chronic tennis elbow.

  13. Use of extracorporeal shock waves in the treatment of tendinopathy and other orthopedic diseases

    Directory of Open Access Journals (Sweden)

    Dushyant Nadar

    2000-01-01

    Full Text Available Objective: Use of extracorporeal shock waves in the treatment of tendinopathy and other orthopedic diseases. Patients and methods: 35 patients received shock wave therapy using Econolith 2000 lithotripter 19 patients had isolated lateral epicondylitis, 12 medical epicondylitis and 4 plantar fascitis. A total of 120 shock waves were given in the first sitting. Each patient received a total of three sittings with a gap of one week between each of them. Results: Based on the patients′ self-assessment, about 75% pain relief was observed in 60% of the patients. Fur-ther, in patients having isolated tendinopathies, the pain relief was better. Conclusion: The study indicated that the application of shock waves is not restricted to the fragmentation of urinary calculi. The shock waves can be effectively used for the pain relief in the common orthopedic diseases. Thus, the urologists can widen the application of lithotripters, in a cost-effective manner, to the other medical speciali-ties.

  14. Double shock front formation in cylindrical radiative blast waves produced by laser irradiation of krypton gas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I.; Quevedo, H. J.; Feldman, S.; Bang, W.; Serratto, K.; McCormick, M.; Aymond, F.; Dyer, G.; Bernstein, A. C.; Ditmire, T. [Center for High Energy Density Science, Department of Physics, The University of Texas at Austin, C1510, Austin, Texas 78712 (United States)

    2013-12-15

    Radiative blast waves were created by irradiating a krypton cluster source from a supersonic jet with a high intensity femtosecond laser pulse. It was found that the radiation from the shock surface is absorbed in the optically thick upstream medium creating a radiative heat wave that travels supersonically ahead of the main shock. As the blast wave propagates into the heated medium, it slows and loses energy, and the radiative heat wave also slows down. When the radiative heat wave slows down to the transonic regime, a secondary shock in the ionization precursor is produced. This paper presents experimental data characterizing both the initial and secondary shocks and numerical simulations to analyze the double-shock dynamics.

  15. Comparative Study of Electromagnetic Waves at the Bow Shocks of Venus and Earth

    Science.gov (United States)

    Wei, Hanying; Russell, Christopher T.; Strangeway, Robert J.; Schwartz, Steven J.; Zhang, Tielong

    2016-04-01

    Although the solar interactions with Venus and Earth are quite different in many ways, they both have bow shocks formed upstream of the planet where the solar wind decelerates from a super- to sub- magnetosonic flow. In the upstream foreshock region, there is abundant wave activity generated by the shock or by the back-streaming ions and electrons from the shock. In the downstream magnetosheath region, there is also abundant wave activity either locally generated by the heated electrons or ions from the shock or transported from the shock or foreshock regions by the solar wind. The magnetometers of Venus Express and Magnetospheric Multiscale missions both occasionally record 128 Hz data during their shock crossing, which allow us the search for and analyze waves at such high frequencies. We have found short-duration wave bursts around both Venus and Earth bow shocks, with certain similarities. These waves are mostly quasi-perpendicular propagating and have amplitude and occurrence rate decreasing with distance from the bow shock. In this paper we perform statistical and comparative studies on wave properties to understand their generation mechanisms and their effects to the shock or magnetosheath plasmas.

  16. Effects of shock waves in the interstellar medium

    Science.gov (United States)

    Petriella, Alberto

    2013-12-01

    In this Thesis, we study the effects on the interstellar medium of shock waves produced by massive stars during different stages of their evolution. We investigate the interaction between HII regions, interstellar bubbles, and supernova remnants and the surrounding medium and we analize the star forming activity to establish if they can trigger star formation around them. We study the distribution of the molecular gas around the supernova remnants G20.0-0.2 and G24.7+0.6 and we find molecular clouds probably shocked by the remnants. These clouds host star forming regions, which suggest a connection between the birth of the new stars and the expansion of the supernova remnants. We analyze the distribution of the interstellar medium around three HII regions (an HII region complex near the supernova remnant G18.8+0.3 and the HII regions N65 and G35.673-0.847) and we find shells of molecular material swept up by their front shocks. These shells show signs of star forming activity probably triggered by the expanding HII regions. Lastly, we find evidence of the interaction between the stellar winds of the LBV stars G24.73+0.69 and G26.47+0.02 and the surrounding molecular gas. The data used in this Thesis were obtained through dedicated observations of several molecular transitions with the Atacama Submillimeter Telescope Experiment (ASTE) and through the calibration of unpublished archival observations of the Chandra X-ray telescope and the VLA interferometer. Additional data were extracted from public surveys in the radio, infrared, millimeter and submillimeter bands.

  17. The effect of high energy shock waves focused on cortical bone: an in vitro study.

    Science.gov (United States)

    Kaulesar Sukul, D M; Johannes, E J; Pierik, E G; van Eijck, G J; Kristelijn, M J

    1993-01-01

    Extracorporeal shock wave lithotripsy has become an accepted alternative for the management of nephrolithiasis and cholelithiasis. Direct impact of shock waves cause tear and shear forces at transition sites between tissues with divergent acoustic impedances leading to stone fragmentation. The aim of this study was to determine whether shock waves can cause cortical bone damage at all and, if so, what the relationship is, if any, between the energy density of the shock waves, the number of shock waves applied, and the resulting cortical bone damage. With the Siemens Lithostar Plus with overhead module, electromagnetic shock waves, generated under water with energy densities of 0.23, 0.33, 0.42, or 0.54 mJ/mm2, corresponding with power settings 2, 4, 6, and 8, were applied to bone specimens, i.e., of rabbit femurs and tibiae. Prior to exposure to the shock waves, the bones were mounted on a specially constructed perspex holder which could be placed in a water-filled test basin with an elastic membrane in the front through which the shock waves propagate without loss of energy. This setup made it possible not only to induce complete fractures, but also to detect the existence of a linear relationship with a Spearman rank correlation coefficient of -0.72 (P < or = 0.01) between the energy level of the shock waves and the severity of the cortical bone defects. The latter findings are especially of great importance because this means that the process can be controlled and that the cortical effects will be predictable and reproducible. This study should be considered a preliminary test concerning the effects of high energy shock wave on bone.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Radial extracorporeal shock wave therapy for heterotopic ossification.

    Science.gov (United States)

    Ryu, Byung-Ju; Ha, Kang-Wook; Lee, Jin-Young; Kim, Sung-Hwan; Kwak, Ho-Jun; Seol, Pyong-Hwa

    2016-01-01

    [Purpose] To report the effects of radial extracorporeal shock wave therapy (RSWT) on heterotopic ossification (HO). [Subjects and Methods] Two cases of neurogenic HO in the upper extremity were administered RSWT using the MASTER PLUS(®) MP 2000 (Storz, Tägerwilen, Switzerland) and ultrasonographic guidance. The RSWT protocol consisted of 3,000 pulses at a frequency of 12 Hz during each treatment. The intensity level ranged from 2-5 bars, and it was administered 5 times a week for 4 weeks, a total of 20 treatments. [Results] RSWT improved pain, range of motion, and hand function in 2 patients with neurogenic HO in the upper extremity. [Conclusion] Further studies are needed to support these results and to understand the mechanism and to devise the protocol of RSWT for neurogenic HO.

  19. Patient information leaflets for extracorporeal shock wave lithotripsy: questionnaire survey

    Science.gov (United States)

    Askari, A; Shergill, I

    2012-01-01

    Objectives To compare the level of information provided in extracorporeal shock wave lithotripsy (ESWL) patient information leaflets in the London and East of England Deaneries Design All trusts in the London and East of England Deanery who offer an ESWL service were contacted and leaflets were compared Setting London and East of England Deanery Participants Alan Askari, Iqbal Shergill Main outcome measures Examination of key information that was communicated to ESWL patients via leaflets Results 12 trusts responded across the two deaneries. There was significant variation in the amount of information provided in the leaflets with some leaflets not containing an adequate level of instruction or information to patients Conclusions The authors propose that a national standardised information leaflet should be incorporated with the British Association of Urological Surgeons (BAUS) procedure specific information leaflet for ESWL procedures PMID:22666532

  20. [Severe pulmonary contusion after extracorporeal shock wave lithotripsy].

    Science.gov (United States)

    Samkaoui, M A; Ziadi, A; Harifi, G; El Adib, A Rhassan; Younous, S

    2009-03-01

    Extracorporeal shock wave lithotripsy (ESWL) is a simple and effective treatment of urinary stones. Renowned less aggressive than surgery, it knew a wide success and constitutes therefore the treatment of first intention of the majority of the kidney stones. Nevertheless, traumatic renal and extrarenal complications notably in lung can arise after ESWL. We report the case of a 28-year-old patient who had a pulmonary contusion following a lithotripsy for a left kidney stone and whose evolution was favourable after two weeks in intensive care unit. Through this observation and the analysis of the rare reported cases in the literature, we insist on the different varieties of pulmonary complications of the ESWL, the hypothesis explaining the mechanisms of their arising as well as the precautions to take to avoid them.

  1. Stenting and extracorporeal shock wave lithotripsy in chronic pancreatitis

    DEFF Research Database (Denmark)

    Holm, M; Matzen, Peter

    2003-01-01

    BACKGROUND: Early observational studies of endoscopic treatment and extracorporeal shock wave lithotripsy (ESWL) reported considerable or complete relief of pain in 50%-80% of patients with chronic pancreatitis. There is no consensus on the measurement of pain, making comparison of observational...... studies difficult, and little attention has been paid to the type and amount of analgesics used by patients before and after decompressive treatment. METHODS: We performed a retrospective study of all patients with chronic pancreatitis and large-duct disease and receiving decompressing treatment between 1...... November 1994 and 31 July 1999. Primary parameters were type and amount of analgesics used. RESULTS: Forty-nine patients with chronic pancreatitis and large-duct disease received stenting of the pancreatic duct (28 patients), ESWL (6 patients) or both (15 patients). After a median follow-up of 21 months...

  2. Approach to Residual Kidney Stone Fragments After Shock Wave Therapy

    Directory of Open Access Journals (Sweden)

    Tumay Ižpekci

    2014-04-01

    Full Text Available For kidney stones up to 2 cm in diameter shock wave therapy (SDT is safely applied and kidney stones smaller than 5mm remaining in the kidney after treatment are regarded as clinically insignificant. Management of this condition is still controversial among clinicians. These stones in the kidney may continue to persist without any clinical symptoms or begin to cause clinical signs. In the event that the clinical symptoms are present, it requires detailed urological examination and treatment. The aim in the surgical treatment of urinary tract stones is completely stone clearance but in stones that are not infected, not causing urinary tract obstruction and without clinical symptoms medical treatment is also beneficial fort he prevention of growth and recurrence. In addition, surgical intervention is also possible for the residual stone fragments which become symptomatic during follow-up.

  3. A new shock wave assisted wood preservative injection system

    Science.gov (United States)

    Rao, K. S.; Ravikumar, G.; Lai, Ram; Jagadeesh, G.

    Preservative treatment of many tropical hard woods and bamboo pose severe problem. A number of wood preservatives (chemical formulations toxic to wood decay/ destroying organisms like fungi, wood destroying termites, marine borers etc.) and wood impregnating techniques are currently in use for improving bio resistance of timber and bamboo and thereby enhancing service life for different end uses. How ever, some species of tropical hardwoods and many species of bamboo are difficult to treat, posing technical problems. In this paper we report preliminary results of treatment of bamboo with a novel Shockwave assisted injection treatment. Samples (30×2.5×1.00 cm) of an Indian species of bamboo Dendrocalamus strictus prepared from defect free culms of dry bamboo are placed in the driven section of a vertical shock tube filled with the 4Coppepr-Chrome-Arsenic(CCA) preservative solution.The bamboo samples are subjected to repeated shock wave loading (3 shots) with typical over pressures of 30 bar. The results from the study indicate excellent penetration and retention of CCA preservative in bamboo samples. The method itself is much faster compared to the conventional methods like pressure treatment or hot and cold process.

  4. Shock wave evolution and discontinuity propagation for relativistic superfluid hydrodynamics with spontaneous symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Sun, E-mail: szhang@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Key Laboratory of Dark Matter and Space Astronomy, Chinese Academy of Sciences, Nanjing 210008 (China); Joint Center for Particle, Nuclear Physics and Cosmology (J-CPNPC), PMO-NJU, Nanjing 210008 (China)

    2014-02-05

    In this Letter, we have studied the shock wave and discontinuity propagation for relativistic superfluid with spontaneous U(1) symmetry breaking in the framework of hydrodynamics. General features of shock waves are provided, the propagation of discontinuity and the sound modes of shock waves are also presented. The first sound and the second sound are identified as the propagation of discontinuity, and the results are in agreement with earlier theoretical studies. Moreover, a differential equation, called the growth equation, is obtained to describe the decay and growth of the discontinuity propagating along its normal trajectory. The solution is in an integral form and special cases of diverging waves are also discussed.

  5. Effects of shock waves on growth of endothelial cells in vitro

    Science.gov (United States)

    Tamagawa, Masaaki; Kitayama, Masanobu; Iwakura, Seiya

    2005-04-01

    Recently shock wave phenomena in living tissues are being widely applied in the fields of medical and chemical engineering, such as extracorporeal shock wave lithotripsy, bioprocess for environmental protection and tissue engineering. In the field of tissue engineering, the bone therapy to regenerate the bone by extracorporeal shock waves shows the possibility for new therapy. In this paper, to investigate the effects of shock waves on the endothelial cells in vitro, the cells by plane shock waves are observed by microscope and the growth rate and others are measured by image processing. The peak pressure works on the endothelial cells in water at the test case is 0.4 MPa. After working shock waves on suspended cells and fixed cells, the disintegration, shape and growth are investigated. It is found that the younger generation cells have small differences of shape index, and the growth rate of the shock-worked cells from 0 to 4 h are clearly high compared with control ones. It is concluded that once shock waves worked, some of them are disintegrated, but the other has capacity to increase growth rate of cell culture in vitro.

  6. Shock Wave Therapy Promotes Cardiomyocyte Autophagy and Survival during Hypoxia

    Directory of Open Access Journals (Sweden)

    Ling Du

    2017-06-01

    Full Text Available Background: Autophagy plays an important role in cardiovascular disease. Controversy still exists regarding the effect of autophagy on ischemic/hypoxic myocardium. Cardiac shock wave therapy (CSWT is an effective alternative treatment for refractory ischemic heart disease. Whether CSWT can regulate cardiomyocyte autophagy under hypoxic conditions is not clear. We established a myocardial hypoxia model using the H9c2 cell line and performed shock waves (SWs treatment to evaluate the effect of SW on autophagy. Methods: The H9c2 cells were incubated under hypoxic conditions, and SW treatment was then performed at energies of 0.02, 0.05, or 0.10 mJ/mm2. The cell viability and intracellular ATP level were examined. Western blot analysis was used to assess the expression of LC3B, AMPK, mTOR, Beclin-1, Sirt1, and HIF-1α. Autophagic vacuoles were visualized by monodansylcadaverine staining. Results: After the 24-hour hypoxic period, cardiomyocyte viability and ATP levels were decreased and autophagy was significantly increased in H9c2 cells. SW treatment with an energy of 0.05 mJ/mm2 significantly increased the cellular viability, ATP level, LC3B-II/I, and number of autophagic vacuoles. In addition, phosphorylated AMPK and Sirt1 were increased and phosphorylated mTOR and HIF-1α were decreased after SW treatment. Conclusion: SW treatment can potentially promote cardiomyocyte autophagy during hypoxia and protect cardiomyocyte function by regulating the AMPK/mTOR pathway.

  7. Nonlinear Shock and Kink Waves with Complete Coriolis Force in Earth's Atmosphere

    Institute of Scientific and Technical Information of China (English)

    YU Xin; ZHAO Qiang

    2009-01-01

    Nonlinear waves in a Boussinesq fluid model which includes both the vertical and horizontal components of Coriolis force are studied by using the semi-geostrophic approximation and the method of travelling-wave solution.Taylor series expansion has been employed to isolate the characteristics of the linear Rossby waves and to identify the nonlinear shock and kink waves.The KdV-Burgers and the compound KdV-Burgers equations are derived,their shock wave and kink wave solution are also obtained.

  8. Extracorporeal shock wave therapy in pillar pain after carpal tunnel release: a preliminary study.

    Science.gov (United States)

    Romeo, Pietro; d'Agostino, M Cristina; Lazzerini, A; Sansone, Valerio C

    2011-10-01

    "Pillar pain" is a relatively frequent complication after surgical release of the median nerve at the wrist. Its etiology still remains unknown although several studies highlight a neurogenic inflammation as a possible cause. Pillar pain treatment usually includes rest, bracing and physiotherapy, although a significant number of patients still complain of painful symptoms two or even three years after surgery. The aim of this study was to investigate the efficacy of low-energy, flux density-focused extracorporeal shock wave therapy (ESWT) in the treatment of pillar pain. We treated 40 consecutive patients with ESWT who had pillar pain for at least six months after carpal tunnel release surgery, and to our knowledge, this is the first study that describes the use of ESWT for treating this condition. Our results show that in all of the treated patients, there was a marked improvement: the mean visual analogue scale (VAS) score decreased from 6.18 (±1.02) to 0.44 (±0.63) 120 d after treatment, and redness and swelling of the surgical scar had also decreased significantly.

  9. Large-Amplitude Electrostatic Waves Observed at a Supercritical Interplanetary Shock

    Science.gov (United States)

    Wilson, L. B., III; Cattell, C. A.; Kellogg, P. J.; Goetz, K.; Kersten, K.; Kasper, J. C.; Szabo, A.; Wilber, M.

    2010-01-01

    We present the first observations at an interplanetary shock of large-amplitude (> 100 mV/m pk-pk) solitary waves and large-amplitude (approx.30 mV/m pk-pk) waves exhibiting characteristics consistent with electron Bernstein waves. The Bernstein-like waves show enhanced power at integer and half-integer harmonics of the cyclotron frequency with a broadened power spectrum at higher frequencies, consistent with the electron cyclotron drift instability. The Bernstein-like waves are obliquely polarized with respect to the magnetic field but parallel to the shock normal direction. Strong particle heating is observed in both the electrons and ions. The observed heating and waveforms are likely due to instabilities driven by the free energy provided by reflected ions at this supercritical interplanetary shock. These results offer new insights into collisionless shock dissipation and wave-particle interactions in the solar wind.

  10. Upstream waves and particles /Tutorial Lecture/. [from shocks in interplanetary space

    Science.gov (United States)

    Russell, C. T.; Hoppe, M. M.

    1983-01-01

    The plasma waves, MHD waves, energetic electrons and ions associated with the proximity of the region upstream from terrestrial, planetary and interplanetary shocks are discussed in view of observations and current theories concerning their origin. These waves cannot be separated from the study of shock structure. Since the shocks are supersonic, they continually overtake any ULF waves created in the plasma in front of the shock. The upstream particles and waves are also of intrinsic interest because they provide a plasma laboratory for the study of wave-particle interactions in a plasma which, at least at the earth, is accessible to sophisticated probing. Insight may be gained into interstellar medium cosmic ray acceleration through the study of these phenomena.

  11. Emission of Whistler-mode waves and diffusion of electrons around interplanetary shocks

    Science.gov (United States)

    Pierre, F.; Solomon, J.; Cornilleau-Wehrlin, N.; Canu, P.; Scime, E. E.; Phillips, J. L.; Balogh, A.; Forsyth, R.

    1995-01-01

    Whistler-mode wave emissions are frequently observed at and downstream of interplanetary shocks. Using electron distribution functions measured onboard Ulysses in the energy range 1.6 to 862 eV, we calculate the temperature anisotropy and the wave growth rate of the electromagnetic electron cyclotron instability, Results of the calculations are compared to the whistler wave spectra observed simultaneously. For the studied events there is a good correlation between the wave growth rates and the wave spectra. Particularly, upstream of the shock front where no wave emissions are observed, the anisotropy lies below the wave instability threshold, i.e. the critical anisotropy Ac; on the contrary, downstream of the shock, the anisotropy exceeds Ac in some frequency range. Moreover. the tact that the anisotropy is close to Ac in a large frequency range gives prominence to the effect of velocity space diffusion of the electrons by the waves.

  12. Characteristics of Hydraulic Shock Waves in an Inclined Chute Contraction by Using Three Dimensional Numerical Model

    Science.gov (United States)

    Hsiao, Kai-Wen; Hsu, Yu-Chao; Jan, Chyan-Deng; Su, Yu-Wen

    2016-04-01

    The inclined rectangular chute construction is a common structure used in hydraulic engineering for typical reasons such as the increase of bottom slope, the transition from side channel intakes to tunnel spillways, the drainage construction, and the reduction of chute width due to bridges, flood diversion structures or irrigation systems. The converging vertical sidewalls of a chute contraction deflect the supercritical flow to form hydraulic shock waves. Hydraulic shock waves have narrow and locally extreme wavy surfaces, which commonly results in the requirement of higher height of sidewalls. Therefore, predicting the possible height and position of maximum hydraulic shock wave are necessary to design the required height of sidewalls to prevent flow overtopping. In this study, we used a three-dimensional computation fluid dynamics model (i.e., FLOW-3D) to simulate the characteristics of hydraulic shock waves in an inclined chute contraction. For this purpose, the parameters of simulated hydraulic shock wave, such as the shock angle, maximum shock wave height and maximum shock wave position in various conditions are compared with those calculated by the empirical relations obtained from literatures. We showed that the simulated results are extremely close to the experimental results. The numerical results validated the applicability of these empirical relations and extend their applicability to higher approach Froude numbers from 3.51 to 7.27. Furthermore, we also applied the Yuan-Shan-Tsu flood diversion channel under 200-year peak flow condition to FLOW-3D model to simulate the hydraulic shock waves and validate the effect of the installation of a diversion pier in the channel on promoting the stability of flow fluid. The results revealed that a diversion pier installed in the Yuan-Shan-Tsu flood diversion channel is helpful for improving the stability of flow field. In summary, this study demonstrates that FLOW-3D model can be used to simulate the

  13. Tailoring the Blast Exposure Conditions in the Shock Tube for Generating Pure, Primary Shock Waves: The End Plate Facilitates Elimination of Secondary Loading of the Specimen.

    Science.gov (United States)

    Kuriakose, Matthew; Skotak, Maciej; Misistia, Anthony; Kahali, Sudeepto; Sundaramurthy, Aravind; Chandra, Namas

    2016-01-01

    The end plate mounted at the mouth of the shock tube is a versatile and effective implement to control and mitigate the end effects. We have performed a series of measurements of incident shock wave velocities and overpressures followed by quantification of impulse values (integral of pressure in time domain) for four different end plate configurations (0.625, 2, 4 inches, and an open end). Shock wave characteristics were monitored by high response rate pressure sensors allocated in six positions along the length of 6 meters long 229 mm square cross section shock tube. Tests were performed at three shock wave intensities, which was controlled by varying the Mylar membrane thickness (0.02, 0.04 and 0.06 inch). The end reflector plate installed at the exit of the shock tube allows precise control over the intensity of reflected waves penetrating into the shock tube. At the optimized distance of the tube to end plate gap the secondary waves were entirely eliminated from the test section, which was confirmed by pressure sensor at T4 location. This is pronounced finding for implementation of pure primary blast wave animal model. These data also suggest only deep in the shock tube experimental conditions allow exposure to a single shock wave free of artifacts. Our results provide detailed insight into spatiotemporal dynamics of shock waves with Friedlander waveform generated using helium as a driver gas and propagating in the air inside medium sized tube. Diffusion of driver gas (helium) inside the shock tube was responsible for velocity increase of reflected shock waves. Numerical simulations combined with experimental data suggest the shock wave attenuation mechanism is simply the expansion of the internal pressure. In the absence of any other postulated shock wave decay mechanisms, which were not implemented in the model the agreement between theory and experimental data is excellent.

  14. Temperature measurement using ultraviolet laser absorption of carbon dioxide behind shock waves.

    Science.gov (United States)

    Oehlschlaeger, Matthew A; Davidson, David F; Jeffries, Jay B

    2005-11-01

    A diagnostic for microsecond time-resolved temperature measurements behind shock waves, using ultraviolet laser absorption of vibrationally hot carbon dioxide, is demonstrated. Continuous-wave laser radiation at 244 and 266 nm was employed to probe the spectrally smooth CO2 ultraviolet absorption, and an absorbance ratio technique was used to determine temperature. Measurements behind shock waves in both nonreacting and reacting (ignition) systems were made, and comparisons with isentropic and constant-volume calculations are reported.

  15. Shock-associated MHD waves - A model for interstellar density fluctuations

    Science.gov (United States)

    Spangler, Steven R.

    1988-01-01

    The possibility that the density fluctuations responsible for radio scintillations could be due to ion-beam-generated MHD waves near interstellar shock waves is discussed. This suggestion is inspired by spacecraft observations which reveal these phenomena near shocks in the solar system. The model quite naturally accounts for the scale on which these fluctuations occur; it is dictated by the wavelength of the unstable waves.

  16. Magnetogasdynamic Cylindrical Shock Waves in a Rotating Nonideal Gas with Radiation Heat Flux

    Science.gov (United States)

    Vishwakarma, J. P.; Patel, Nanhey

    2015-03-01

    A similarity solution is presented for a cylindrical magnetogasdynamic shock wave in a rotating nonideal gas in the presence of a variable axial magnetic field in the case where the radiation heat flux is of importance. The initial angular velocity of the medium is assumed to vary as some power of the distance from the symmetry axis. The radiation heat flux is evaluated from the equation of motion without explicit use of the radiation transfer equations. It is shown that the gas nonidealness increases the shock strength but decreases the shock velocity. On the other hand, the presence of a magnetic field decreases the shock strength but increases the shock velocity. Moreover, the shock velocity increases with the ratio of specific heats. The total energy of the shock wave increases with time.

  17. Scattering of ultrasonic shock waves in suspensions of silica nanoparticles.

    Science.gov (United States)

    Baudoin, Michael; Thomas, Jean-Louis; Coulouvrat, François; Chanéac, Corinne

    2011-03-01

    Experiments are carried out to assess, for the first time, the validity of a generalized Burgers' equation, introduced first by Davidson [J. Acoust. Soc. Am. 54, 1331-1342 (1973)] to compute the nonlinear propagation of finite amplitude acoustical waves in suspensions of "rigid" particles. Silica nanoparticles of two sizes (33 and 69 nm) have been synthesized in a water-ethanol mixture and precisely characterized via electron microscopy. An acoustical beam of high amplitude is generated at 1 MHz inside a water tank, leading to the formation of acoustical shock waves through nonlinear steepening. The signal is then measured after propagation in a cylinder containing either a reference solution or suspensions of nanoparticles. In this way, a "nonlinear attenuation" is obtained and compared to the numerical solution of a generalized Burgers' equation adapted to the case of hydrosols. An excellent agreement (corresponding to an error on the particles size estimation of 3 nm) is achieved in the frequency range from 1 to 40 MHz. Both visco-inertial and thermal scattering are significant in the present case, whereas thermal effects can generally be neglected for most hydrosols. This is due to the value of the specific heat ratio of water-ethanol mixture which significantly differs from unity.

  18. Oxy-acetylene driven laboratory scale shock tubes for studying blast wave effects.

    Science.gov (United States)

    Courtney, Amy C; Andrusiv, Lubov P; Courtney, Michael W

    2012-04-01

    This paper describes the development and characterization of modular, oxy-acetylene driven laboratory scale shock tubes. Such tools are needed to produce realistic blast waves in a laboratory setting. The pressure-time profiles measured at 1 MHz using high-speed piezoelectric pressure sensors have relevant durations and show a true shock front and exponential decay characteristic of free-field blast waves. Descriptions are included for shock tube diameters of 27-79 mm. A range of peak pressures from 204 kPa to 1187 kPa (with 0.5-5.6% standard error of the mean) were produced by selection of the driver section diameter and distance from the shock tube opening. The peak pressures varied predictably with distance from the shock tube opening while maintaining both a true blast wave profile and relevant pulse duration for distances up to about one diameter from the shock tube opening. This shock tube design provides a more realistic blast profile than current compression-driven shock tubes, and it does not have a large jet effect. In addition, operation does not require specialized personnel or facilities like most blast-driven shock tubes, which reduces operating costs and effort and permits greater throughput and accessibility. It is expected to be useful in assessing the response of various sensors to shock wave loading; assessing the reflection, transmission, and absorption properties of candidate armor materials; assessing material properties at high rates of loading; assessing the response of biological materials to shock wave exposure; and providing a means to validate numerical models of the interaction of shock waves with structures. All of these activities have been difficult to pursue in a laboratory setting due in part to lack of appropriate means to produce a realistic blast loading profile.

  19. Classical and Quantum Strings in plane waves, shock waves and spacetime singularities synthesis and new results

    CERN Document Server

    Sánchez, N G

    2003-01-01

    Key issues of classical and quantum strings in gravitational plane waves, shock waves and spacetime singularities are synthetically understood. This includes the string mass and mode number excitations, energy-momentum tensor, scattering amplitudes, vacuum polarization and wave-string polarization effect. The role of the real pole singularities characteristic of the tree level string spectrum (real mass resonances) and that of spacetime singularities is clearly exhibited. This throws light on the issue of singularities in string theory which can be thus classified and fully physically characterized in two different sets: strong singularities (poles of order equal or larger than 2, and black holes), where the string motion is collective and non oscillating in time, outgoing and scattering states do not appear, the string does not cross the singularities, and weak singularities (poles of order smaller than 2, Dirac delta, and conic/orbifold singularities) where the whole string motion is oscillatory in time, ou...

  20. Experimental study of diverging and converging spherical shock waves and their interaction with product gases

    Science.gov (United States)

    Hosseini, S. H. R.; Takayama, K.

    The paper reports an experimental study of production and propagation of diverging and converging spherical shock waves. In order to quantitatively observe spherical shock waves and the flow field behind them, an aspheric spherical transparent test section was designed and constructed. This 150 mm inner-diameter aspheric lens shaped test section permits the collimated visualization laser light beam to traverse the test section parallel and emerge parallel. Spherical diverging shock waves were produced at the center of the spherical test section. In order to generate shock waves, irradiation of a pulsed Nd:YAG laser beam on micro silver azide pellets were used. The weight of silver azide pellets ranged from 1 to 10 mg, with their corresponding energy of 1.9 to 19 J. Pressure histories at two points over the test section were measured. After reflection of spherical shock wave from the test section, a converging spherical shock wave was produced. Double exposure holographic interferometry and time resolved high speed photography were used for flow visualization. The whole sequence of diverging and converging spherical shock waves propagation and their interaction with product gases were studied.

  1. Effect of shock wave risetime on material ejection from aluminum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Asay, J.R.

    1977-09-15

    The effect of shock wave risetime on material ejection in aluminum has been studied for loading stresses of 21 GPa. Uniform loading was accomplished with plate impact techniques by mounting specimens on a ramp wave generator. Projectile impact on one side of the wave generator produced a wave which dispersed with propagation distance. This wave was then made incident to an aluminum specimen, so that the specimen experienced non-shock loading. It was found that mass ejection from aluminum surfaces can be reduced by over two orders of magnitude relative to shock loading conditions by accelerating the surface with a wave risetime greater than about 35 ns. These results suggest an explanation for the apparent discrepancies which are sometimes observed in mass ejection measurements utilizing either plate impact or electron beam deposition to generate stress waves.

  2. Shock Wave Speed and Transient Response of PE Pipe with Steel-Mesh Reinforcement

    OpenAIRE

    2016-01-01

    A steel mesh can improve the tensile strength and stability of a polyethylene (PE) pipe in a water supply pipeline system. However, it can also cause more severe water hammer hazard due to increasing wave speed. In order to analyze the influence of the steel mesh on the shock wave speed and transient response processes, an improved wave speed formula is proposed by incorporating the equivalent elastic modulus. A field measurement validates the wave speed formula. Moreover, the transient wave ...

  3. Evidence for a thermally unstable shock wave in the VELA supernova remnant

    Science.gov (United States)

    Raymond, John C.; Wallerstein, George; Balick, Bruce

    1991-12-01

    The emission and absorption line signatures of supernova remnant shock waves provide complementary diagnostic capabilities. This paper presents IUE spectra of the nebulosity and new spectra of HD 72088. Models of the emission and absorption lines from shocked gas are used to derive a shock velocity and elemental depletions. There is evidence from the absorption-line strengths and widths for thermally unstable cooling behind a 150 km/s shock. The shock velocity and swept-up column density estimates of Wallerstein and Balick (1990) are confirmed, and evidence is found for a nonthermal contribution to the pressure.

  4. Nonlinear interactions in superfluid dynamics: Nonstationary heat transfer due to second sound shock waves

    Science.gov (United States)

    Liepmann, H. W.; Torczynski, J. R.

    1983-01-01

    Second sound techniques were used to study superfluid helium. Second sound shock waves produced relative velocities in the bulk fluid. Maximum counterflow velocities produced in this way are found to follow the Langer-Fischer prediction for the fundamental critical velocity in its functional dependence on temperature and pressure. Comparison of successive shock and rotating experiments provides strong evidence that breakdown results in vorticity production in the flow behind the shock. Schlieren pictures have verified the planar nature of second sound shocks even after multiple reflections. The nonlinear theory of second sound was repeatedly verified in its prediction of double shocks and other nonlinear phenomena.

  5. An experimental study of shock wave propagation through a polyester film

    Science.gov (United States)

    Eliasson, Veronica; Jeon, Hongjoo

    2016-11-01

    A polyester film is available in a variety of uses such as packaging, protective overlay, barrier protection, and other industrial applications. In the current study, shock tube experiments are performed to study the influence of a polyester film on the propagation of a planar shock wave. A conventional shock tube is used to create incident shock Mach numbers of Ms = 1.34 and 1.46. A test section of the shock tube is designed to hold a 0.009 mm, 0.127 mm, 0.254 mm, or 0.508 mm thick polyester film (Dura-Lar). High-temporal resolution schlieren photography is used to visualize the shock wave mitigation caused by the polyester film. In addition, four pressure transducers are used to measure the elapsed time of arrival and overpressure of the shock wave both upstream and downstream of the test section. Results show that the transmitted shock wave in the polyester film is clearly observed and the transmitted shock Mach number is decreased by increasing film thickness. This study is supported by the National Science Foundation under Grant No. CBET-1437412.

  6. Calibration of a shock wave position sensor using artificial neural networks

    Science.gov (United States)

    Decker, Arthur J.; Weiland, Kenneth E.

    1993-01-01

    This report discusses the calibration of a shock wave position sensor. The position sensor works by using artificial neural networks to map cropped CCD frames of the shadows of the shock wave into the value of the shock wave position. This project was done as a tutorial demonstration of method and feasibility. It used a laboratory shadowgraph, nozzle, and commercial neural network package. The results were quite good, indicating that artificial neural networks can be used efficiently to automate the semi-quantitative applications of flow visualization.

  7. Numerical simulation on propagation and attenuation of shock waves in simplex turn roadway during gas explosion

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Wei; Qu, Zhi-ming; Pian, Long-jiang [University of Science and Technology Beijing, Beijing (China). School of Civil Engineering and Environment

    2009-04-15

    On the basis of a hypothesis, a physical and mathematical model of the propagation of shock waves in turn roadway was set up. The results of numerical simulation show that the pressure, velocity and temperature of shock wave will be attenuated during propagation. At the beginning of gas explosion, the quantity of parameters of shock wave front is increased gradually because of methane reaction. However, the pressure, velocity and temperature will be attenuated to a small extent after the chemical reaction. By comparison of the experiment, simulation and practice, the highly identical data shows that the numerical model is practicable. 9 refs., 7 figs.

  8. Generalized and exact solutions for oblique shock waves of real gases with application to real air

    Science.gov (United States)

    Kouremenos, D. A.; Antonopoulos, K. A.

    1989-12-01

    The present work presents a generalized method for calculating oblique shock waves of real gases, based on the Redlich-Kwong (1949) equation of state. Also described is an exact method applicable when the exact equation of state and enthalpy function of a real gas are available. Application of the generalized and the exact methods in the case of real air showed that the former is very accurate and at least twenty times faster than the latter. An additional contribution of the study is the derivation of real gas oblique shock wave equations, which are of the same algebraic form as the well known ideal gas normal shock wave relations.

  9. SOME PROBLEMS ON JUMP CONDITIONS OF SHOCK WAVES IN 3-DIMENSIONAL SOLIDS

    Institute of Scientific and Technical Information of China (English)

    LI Yong-chi; YAO Lei; HU Xiu-zhang; CAO Jie-dong; DONG Jie

    2006-01-01

    Based on the general conservation laws in continuum mechanics, the Eulerian and Lagrangian descriptions of the jump conditions of shock waves in 3-dimensional solids were presented respectively. The implication of the jump conditions and their relations between each other, particularly the relation between the mass conservation and the displacement continuity, were discussed. Meanwhile the shock wave response curves in 3-dimensional solids, i.e. the Hugoniot curves were analysed, which provide the foundation for studying the coupling effects of shock waves in 3-dimensional solids.

  10. One-dimensional numerical simulation of shock wave propagation induced by vacuum accidents in a beamline

    Energy Technology Data Exchange (ETDEWEB)

    Takiya, Toshio; Terada, Yukihiro; Komura, Akio [Hitachi Zosen Corp., Osaka (Japan); Higashino, Fumio; Miyajima, Shinichi; Ando, Masami

    1997-05-01

    A simulation for shock wave propagation in a vacuum tube has been conducted from the viewpoint of protection from vacuum accidents in beamlines of a synchrotron radiation facility. Inserted devices in beamlines such as absorbers, slits, masks and beryllium windows were replaced with orifices installed in a shock tube as a simulation model. One-dimensional Euler`s equations with friction terms were used for estimating the effects on shock wave decay as well as the effects of friction along a tube on shock attenuation. The results indicated that the entrance diameter of the shock tube was an important parameter for determining the strength of shock waves generated by the expansion of gases at the tube entrance and that the friction effects were too large to delay the arrival time of shock waves at the end of a long tube. Moreover, shock wave propagation in a long beamline model based on the MR beamline in the National Laboratory for High Energy Physics was simulated for designing adequate protection from vacuum accidents. The present simulation provides necessary information for the design of a protection system for vacuum accidents in other facilities. (author)

  11. Time-resolved spectroscopic measurements behind incident and reflected shock waves in air and xenon

    Science.gov (United States)

    Yoshinaga, T.

    1973-01-01

    Time-resolved spectra have been obtained behind incident and reflected shock waves in air and xenon at initial pressures of 0.1 and 1.0 torr using a rotating drum spectrograph and the OSU (The Ohio State University) arc-driven shock tube. These spectra were used to determine the qualitative nature of the flow as well as for making estimates of the available test time. The (n+1,n) and (n,n) band spectra of N2(+) (1st negative) were observed in the test gas behind incident shock waves in air at p1=1.0 torr and Us=9-10 km/sec. Behind reflected shock waves in air, the continuum of spectra appeared to cover almost the entire wavelength of 2,500-7,000 A for the shock-heated test gas. For xenon, the spectra for the incident shock wave cases for p1=0.1 torr show an interesting structure in which two intensely bright regions are witnessed in the time direction. The spectra obtained behind reflected shock waves in xenon were also dominated by continuum radiation but included strong absorption spectra due to FeI and FeII from the moment the reflected shock passed and on.

  12. Analysis of a bubble deformation process in a microcapsule by shock waves for developing DDS

    Science.gov (United States)

    Tamagawa, Masaaki; Morimoto, Kenshi

    2012-09-01

    This paper describes development of DDS (drug delivery systems) microcapsule using underwater shock waves, especially (1) making polymer microcapsules including a bubble and analysis of a bubble deformation process in a polymer capsule by pressure wave, (2) making liposome microcapsules with different elastic membrane and disintegration tests by ultrasonic waves.

  13. A Study of the Complex Flow Features Behind a Diffracted Shock Wave on a Convex Curved Wall

    OpenAIRE

    adam muritala; skews beric; craig law

    2015-01-01

    The complex flow features behind a diffracted shock wave on a convex curved wall is investigated using large scale experimentation complemented by numerical computation. The study aimed at explaining the global flow behavior within the perturbed region behind the diffracted shock wave. Experiments were conducted in a purpose built shock tube that is capable of generating a range of incident shock Mach numbers Mn ≤ 1.6. Analysis of higher Mach number shocks on different wall geometries were ca...

  14. Oscillations at low energies

    CERN Document Server

    Dwyer, D A

    2015-01-01

    A concise summary of the "Oscillation at low energies" parallel session at the 2014 Neutrino Oscillation Workshop is provided. Plans to use man-made neutrinos and antineutrinos to determine the neutrino mass hierarchy, search for sterile neutrinos, and to observe coherent neutrino-nucleus scattering were discussed. Potential measurements of solar neutrinos, supernova neutrinos, and geoneutrinos are also summarized.

  15. Interaction of a weak shock wave with a discontinuous heavy-gas cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiansheng; Yang, Dangguo; Wu, Junqiang [High Speed Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000 (China); Luo, Xisheng, E-mail: xluo@ustc.edu.cn [Advanced Propulsion Laboratory, Department of Modern Mechanics, University of Science and Technology of China, Hefei 230026 (China)

    2015-06-15

    The interaction between a cylindrical inhomogeneity and a weak planar shock wave is investigated experimentally and numerically, and special attention is given to the wave patterns and vortex dynamics in this scenario. A soap-film technique is realized to generate a well-controlled discontinuous cylinder (SF{sub 6} surrounded by air) with no supports or wires in the shock-tube experiment. The symmetric evolving interfaces and few disturbance waves are observed in a high-speed schlieren photography. Numerical simulations are also carried out for a detailed analysis. The refracted shock wave inside the cylinder is perturbed by the diffracted shock waves and divided into three branches. When these shock branches collide, the shock focusing occurs. A nonlinear model is then proposed to elucidate effects of the wave patterns on the evolution of the cylinder. A distinct vortex pair is gradually developing during the shock-cylinder interaction. The numerical results show that a low pressure region appears at the vortex core. Subsequently, the ambient fluid is entrained into the vortices which are expanding at the same time. Based on the relation between the vortex motion and the circulation, several theoretical models of circulation in the literature are then checked by the experimental and numerical results. Most of these theoretical circulation models provide a reasonably good prediction of the vortex motion in the present configuration.

  16. Operation of High-Voltage Transverse Shock Wave Ferromagnetic Generator in the Open Circuit and Charging Modes

    Science.gov (United States)

    2005-06-01

    FMGs are based on the transverse (when the shock wave propagates across the magnetization vector M) shock demagnetization of Nd2Fe14B hard...generators based on the transverse (when the shock wave propagates across the magnetization vector M) shock wave demagnetization of Nd2Fe14B hard...and photo of a high-voltage transverse FMG are shown in Fig. 1. It contains a hollow hard ferromagnetic cylindrical Nd2Fe14B energy-carrying

  17. Epicardial shock-wave therapy improves ventricular function in a porcine model of ischaemic heart disease.

    Science.gov (United States)

    Holfeld, Johannes; Zimpfer, Daniel; Albrecht-Schgoer, Karin; Stojadinovic, Alexander; Paulus, Patrick; Dumfarth, Julia; Thomas, Anita; Lobenwein, Daniela; Tepeköylü, Can; Rosenhek, Raphael; Schaden, Wolfgang; Kirchmair, Rudolf; Aharinejad, Seyedhossein; Grimm, Michael

    2016-12-01

    Previously we have shown that epicardial shock-wave therapy improves left ventricular ejection fraction (LVEF) in a rat model of myocardial infarction. In the present experiments we aimed to address the safety and efficacy of epicardial shock-wave therapy in a preclinical large animal model and to further evaluate mechanisms of action of this novel therapy. Four weeks after left anterior descending (LAD) artery ligation in pigs, the animals underwent re-thoracotomy with (shock-wave group, n = 6) or without (control group, n = 5) epicardial shock waves (300 impulses at 0.38 mJ/mm(2) ) applied to the infarcted anterior wall. Efficacy endpoints were improvement of LVEF and induction of angiogenesis 6 weeks after shock-wave therapy. Safety endpoints were haemodynamic stability during treatment and myocardial damage. Four weeks after LAD ligation, LVEF decreased in both the shock-wave (43 ± 3%, p wave animals 6 weeks after treatment (62 ± 9%, p = 0.006); no improvement was observed in controls (41 ± 4%, p = 0.36), yielding a significant difference. Quantitative histology revealed significant angiogenesis 6 weeks after treatment (controls 2 ± 0.4 arterioles/high-power field vs treatment group 9 ± 3; p = 0.004). No acute or chronic adverse effects were observed. As a potential mechanism of action in vitro experiments showed stimulation of VEGF receptors after shock-wave treatment in human coronary artery endothelial cells. Epicardial shock-wave treatment in a large animal model of ischaemic heart failure exerted a positive effect on LVEF improvement and did not show any adverse effects. Angiogenesis was induced by stimulation of VEGF receptors. Copyright © 2014 John Wiley & Sons, Ltd.

  18. Extracorporeal shock wave therapy in orthopedics, basic research, and clinical implications

    Science.gov (United States)

    Hausdorf, Joerg; Jansson, Volkmar; Maier, Markus; Delius, Michael

    2005-04-01

    The molecular events following shock wave treatment of bone are widely unknown. Nevertheless patients with osteonecrosis and non unions are already treated partly successful with shock waves. Concerning the first indication, the question of the permeation of the shock wave into the bone was addressed. Therefore shockwaves were applied to porcine femoral heads and the intraosseous pressure was measured. A linear correlation of the pressure to the intraosseous distance was found. Approximately 50% of the pressure are still measurable 10 mm inside the femoral head. These findings should encourage continued shock wave research on this indication. Concerning the second indication (non union), osteoblasts were subjected to 250 or 500 shock waves at 25 kV. After 24, 48, and 72 h the levels of the bone and vascular growth factors bFGF, TGFbeta1, and VEGF were examined. After 24 h there was a significant increase in bFGF levels (pshock wave treatment and may lead to a more specific application of shock waves in orthopedic surgery.

  19. Reflection of a strong magnetic-gas-dynamic shock wave from an elliptical cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Gorbachev, L.P.; Sokolov, V.B.

    1977-10-01

    A study is made of a strong, plane shock wave with uniform parameters propagating in a gas with infinite electric conductivity when a homogeneous magnetic field is present tangential to the leading edge of the shock wave when the wave encounters an elliptical cylinder which is stationary in the direction of propagation of the shock wave. The generatrix of the cylinder is parallel to the magnetic field, and the shock wave moves along one of the semiaxes of the ellipse in the perpendicular cross section of the cylinder. Expressions are derived for the flow parameters of the gas beyond the reflected shock wave, ignoring the viscosity and heat conductivity of the gas and assuming the Hall effect to be slight. As t ..-->.. infinity steady supersonic flow is established around the cylinder and the velocity D of the reflected shock wave with respect to the cylinder drops toward zero. A graph shows the results of calculation of the pressure on the surface of the cylinder. 7 references, 1 figure.

  20. Nonlinear Gamow vectors, shock waves and irreversibility in optically nonlocal media

    CERN Document Server

    Gentilini, Silvia; Marcucci, Giulia; DelRe, Eugenio; Conti, Claudio

    2015-01-01

    Dispersive shock waves dominate wave-breaking phenomena in Hamiltonian systems. In the absence of loss, these highly irregular and disordered waves are potentially reversible. However, no experimental evidence has been given about the possibility of inverting the dynamics of a dispersive shock wave and turn it into a regular wave-front. Nevertheless, the opposite scenario, i.e., a smooth wave generating turbulent dynamics is well studied and observed in experiments. Here we introduce a new theoretical formulation for the dynamics in a highly nonlocal and defocusing medium described by the nonlinear Schroedinger equation. Our theory unveils a mechanism that enhances the degree of irreversibility. This mechanism explains why a dispersive shock cannot be reversed in evolution even for an arbitrarirly small amount of loss. Our theory is based on the concept of nonlinear Gamow vectors, i.e., power dependent generalizations of the counter-intuitive and hereto elusive exponentially decaying states in Hamiltonian sys...

  1. Efficient transformation of Mycosphaerella fijiensis by underwater shock waves.

    Science.gov (United States)

    Escobar-Tovar, Lina; Magaña-Ortíz, Denis; Fernández, Francisco; Guzmán-Quesada, Mauricio; Sandoval-Fernández, Jorge A; Ortíz-Vázquez, Elizabeth; Loske, Achim M; Gómez-Lim, Miguel A

    2015-12-01

    Black leaf streak disease, also known as black Sigatoka, causes dramatic losses in production of banana and plantains fruits. The disease is caused by the pathogenic fungus Mycosphaerella fijiensis (anamorph Pseudocercospora fijiensis; Mycosphaerellaceae). Genetic transformation of M. fijiensis would allow a better understanding of molecular basis of pathogenicity and design novel approaches to control the infection caused by this pathogen. However, transformation of this fungus has not been easy. We report here a protocol for genetic transformation of M. fijiensis employing underwater shock waves and intact conidia. The recombinant strains recovered showed genetic stability over >10 generations. The frequency of transformation obtained was between 75 and 150 times higher than the efficiency reported in the only article published on transformation of M. fijiensis using spheroplasts. This improvement allowed the use of a thousand times less cells than the amount employed before, avoiding the need for cumbersome successive batch cultures. Our protocol is simple, highly efficient, fast and reproducible and together with the available genomes of M. fijiensis and Musa acuminata, it offers new possibilities to study the diverse mechanisms of pathogenesis of the fungus. Copyright © 2015. Published by Elsevier B.V.

  2. Microwave Diagnostics of Shock Wave and Detonation Processes

    Science.gov (United States)

    Mikhaylov, Anatoly; Belsky, Vladimir; Bogdanov, Evgeny; Rodionov, Alexey; Sedov, Alexander; Khvorostin, Vladimir; Russian Federal Nuclear Center-Vniief 607190, Sarov, Nizhniy Novgorod Reg., Russia Team

    2013-06-01

    The physical bases of laser and microwave Doppler interferometry are the same - measurements of the Doppler shift of probing electromagnetic frequency, reflected from a moving surface. However, using probing wavelength 4 orders of magnitude longer, microwave diagnostics has some specific advantages as compared with laser diagnostics, namely: measurements inside the microwave-transparent media, which spectrum is much more wide than the spectrum of optically transparent media; for microwave measurements the reflecting surfaces of media, but all jumps of medium parameters - density, dielectric permittivity, conductivity; for microwave technique due to its wavelength all practically important hydrodynamical jumps are smooth. The results of application of the microwave technique were presented in the paper, which demonstrate capabilities of diagnostics of various dynamic processes using single equipment, namely: liners and massive objects launching; shock-to-detonation transition in HE; propagation of steady detonation waves; laminar HE combustion etc. In all conducted investigations the using of the microwave technique gives a big amount of interesting experimental information which is inaccessible for the other traditional experimental techniques.

  3. Clinical application of shock wave therapy (SWT) in musculoskeletal disorders.

    Science.gov (United States)

    Ioppolo, F; Rompe, J D; Furia, J P; Cacchio, A

    2014-04-01

    Currently the application of shock wave therapy (SWT) in musculoskeletal disorders has been primarily used in the treatment of tendinopathies (proximal plantar fasciopathy, lateral elbow tendinopathy, calcific tendinopathy of the shoulder, and patellar tendinopathy, etc.) and bone defects (delayed- and non-union of bone fractures, avascular necrosis of femoral head, etc.). Although the mechanism of their therapeutic effects are still unknown, the majority of published papers have shown positive and beneficial effects of using SWT as a treatment for musculoskeletal disorders, with a success rate ranging from 65% to 91%, while the complications are low or negligible. The purpose of this paper is to inform the reader about the published data on the clinical application of SWT in the treatment of musculoskeletal disorders. In this paper, with the help of a literature review, indications and success rates for SWT in the treatment of musculoskeletal disorders are outlined, while adequate SWT parameters (e.g., rate of impulses, energy flux density, etc.) are defined according to the present state of knowledge.

  4. Extracorporeal shock wave therapy for calcifying tendinitis of the shoulder.

    Science.gov (United States)

    Hsu, Chin-Jung; Wang, Der-Yean; Tseng, Kuo-Fung; Fong, Yi-Chin; Hsu, Horng-Chaung; Jim, Yick-Fung

    2008-01-01

    We prospectively studied extracorporeal shock wave therapy (ESWT) for calcific tendinitis of the shoulder in 46 consecutive patients. All patients were randomly divided into 2 groups: treatment and control. The 33 patients in the treatment group received 2 courses of ESWT at the energy density of 0.55 mJ/mm(2) (1000 impulses). The control group underwent sham treatment with a dummy electrode (13 patients). Evaluation included the Constant score, pain scale, and radiographs. The ESWT results were good to excellent in 87.9% of shoulders (29/33) and fair in 12.1% (4/33), and the control results were fair in 69.2% (9/13) and poor in 30.1% (4/13). Among ESWT patients, calcium deposits were completely eliminated in 7 cases (21.2%), partially eliminated in 11 (36.3%), and unchanged in 15 (45.4%). In contrast, elimination was partial in 2 control patients (15.3%) and unchanged in 11 (84.7%). There was no significant difference between Gärtner type I and type II groups in the Constant score (P > .05). ESWT shows promise for pain relief and functional restoration of calcific tendinitis with negligible complications.

  5. Pediatric extracorporeal shock wave lithotripsy: Predicting successful outcomes

    Directory of Open Access Journals (Sweden)

    Sean McAdams

    2010-01-01

    Full Text Available Extracorporeal shock wave lithotripsy (ESWL is currently a first-line procedure of most upper urinary tract stones <2 cm of size because of established success rates, its minimal invasiveness and long-term safety with minimal complications. Given that alternative surgical and endourological options exist for the management of stone disease and that ESWL failure often results in the need for repeat ESWL or secondary procedures, it is highly desirable to identify variables predicting successful outcomes of ESWL in the pediatric population. Despite numerous reports and growing experience, few prospective studies and guidelines for pediatric ESWL have been completed. Variation in the methods by which study parameters are measured and reported can make it difficult to compare individual studies or make definitive recommendations. There is ongoing work and a need for continuing improvement of imaging protocols in children with renal colic, with a current focus on minimizing exposure to ionizing radiation, perhaps utilizing advancements in ultrasound and magnetic resonance imaging. This report provides a review of the current literature evaluating the patient attributes and stone factors that may be predictive of successful ESWL outcomes along with reviewing the role of pre-operative imaging and considerations for patient safety.

  6. Intraluminal bubble dynamics induced by lithotripsy shock wave

    Science.gov (United States)

    Song, Jie; Bai, Jiaming; Zhou, Yufeng

    2016-12-01

    Extracorporeal shock wave lithotripsy (ESWL) has been the first option in the treatment of calculi in the upper urinary tract since its introduction. ESWL-induced renal injury is also found after treatment and is assumed to associate with intraluminal bubble dynamics. To further understand the interaction of bubble expansion and collapse with the vessel wall, the finite element method (FEM) was used to simulate intraluminal bubble dynamics and calculate the distribution of stress in the vessel wall and surrounding soft tissue during cavitation. The effects of peak pressure, vessel size, and stiffness of soft tissue were investigated. Significant dilation on the vessel wall occurs after contacting with rapid and large bubble expansion, and then vessel deformation propagates in the axial direction. During bubble collapse, large shear stress is found to be applied to the vessel wall at a clinical lithotripter setting (i.e. 40 MPa peak pressure), which may be the mechanism of ESWL-induced vessel rupture. The decrease of vessel size and viscosity of soft tissue would enhance vessel deformation and, consequently, increase the generated shear stress and normal stresses. Meanwhile, a significantly asymmetric bubble boundary is also found due to faster axial bubble expansion and shrinkage than in radial direction, and deformation of the vessel wall may result in the formation of microjets in the axial direction. Therefore, this numerical work would illustrate the mechanism of ESWL-induced tissue injury in order to develop appropriate counteractive strategies for reduced adverse effects.

  7. Low-energy control of electrical turbulence in the heart

    Science.gov (United States)

    Luther, Stefan; Fenton, Flavio H.; Kornreich, Bruce G.; Squires, Amgad; Bittihn, Philip; Hornung, Daniel; Zabel, Markus; Flanders, James; Gladuli, Andrea; Campoy, Luis; Cherry, Elizabeth M.; Luther, Gisa; Hasenfuss, Gerd; Krinsky, Valentin I.; Pumir, Alain; Gilmour, Robert F.; Bodenschatz, Eberhard

    2011-07-01

    Controlling the complex spatio-temporal dynamics underlying life-threatening cardiac arrhythmias such as fibrillation is extremely difficult, because of the nonlinear interaction of excitation waves in a heterogeneous anatomical substrate. In the absence of a better strategy, strong, globally resetting electrical shocks remain the only reliable treatment for cardiac fibrillation. Here we establish the relationship between the response of the tissue to an electric field and the spatial distribution of heterogeneities in the scale-free coronary vascular structure. We show that in response to a pulsed electric field, E, these heterogeneities serve as nucleation sites for the generation of intramural electrical waves with a source density ρ(E) and a characteristic time, τ, for tissue depolarization that obeys the power law τ~Eα. These intramural wave sources permit targeting of electrical turbulence near the cores of the vortices of electrical activity that drive complex fibrillatory dynamics. We show in vitro that simultaneous and direct access to multiple vortex cores results in rapid synchronization of cardiac tissue and therefore, efficient termination of fibrillation. Using this control strategy, we demonstrate low-energy termination of fibrillation in vivo. Our results give new insights into the mechanisms and dynamics underlying the control of spatio-temporal chaos in heterogeneous excitable media and provide new research perspectives towards alternative, life-saving low-energy defibrillation techniques.

  8. Influence of deposited energy on shock wave induced by underwater pulsed current discharge

    Science.gov (United States)

    Li, Xian-Dong; Liu, Yi; Liu, Si-Wei; Li, Zhi-Yuan; Zhou, Gu-Yue; Li, Hua; Lin, Fu-Chang; Pan, Yuan

    2016-10-01

    In this paper, an integrated experimental system is established to study the influence of deposited energy on the intensity of the shock wave induced by underwater pulse discharge. Considering the time varying behavior of the arc, the calculation methods of the deposited energy into the plasma channel and the average arc resistance are proposed and presented. The effect of the breakdown process on the deposited energy and the shock wave is analyzed. It can be concluded that the shock wave intensity can be improved by depositing more energy in the first half oscillation period and increasing the arc resistance. It is also found that the energy deposition and the shock wave intensity are significantly influenced by the breakdown time delay and the shape of the initial plasma channel.

  9. Theoretical study of nonlinear waves and shock-like phenomena in hot plasmas

    Science.gov (United States)

    Fried, B. D.; Banos, A., Jr.; Kennel, C. F.

    1973-01-01

    Summaries are presented of research in basic plasma physics. Nonlinear waves and shock-like phenomena were studied which are pertinent to space physics applications, and include specific problems of magnetospheric and solar wind plasma physics.

  10. Development of a system of automatic gap-adjusted electrodes for shock wave generators

    Science.gov (United States)

    Manousakas, Ioannis; Liang, Shen-Min; Wan, Long-Ray; Wang, Chia-Hui

    2004-11-01

    In this study, a system of automatic gap-adjusted electrodes is developed for electrohydraulic shock wave generators that can be used both for extracorporeal shock wave lithotripsy (treatment of renal calculi) and for the extracorporeal shock wave therapy for musculo-skeletal disorders. This system is composed of three main components: (1) two electrodes and their bases; (2) servo motors and control software; (3) a high sensitivity CCD camera and image processing program. To verify system performance, in vitro fragmentation tests have been conducted using kidney stone phantoms. Results indicate that the efficiency of stone fragmentation using automatic gap adjustment can be increased up to 55.2%, which is twice more than without automatic gap adjustment (26.7%). This system can be applied to any commercial electrohydraulic extracorporeal shock wave lithotriptor or orthotriptor without difficulty.

  11. Liver fibrosis after extracorporeal shock-wave lithotripsy of gallbladder stones - A case report

    NARCIS (Netherlands)

    P.W. Plaisier; J.F. Hamming (Jaap); R.L. van der Hul (René); R. den Toom (Rene); H.A. Bruining (Hajo)

    1994-01-01

    textabstractWe encountered significant liver fibrosis in a healthy young patient undergoing laparoscopic cholecystectomy for symptomatic gallstone disease. Twelve months prior to cholecystectomy the patient underwent multiple extracorporeal shock-wave lithotripsy (ESWL) sessions with adjuvant oral b

  12. Shock wave application to rat skin induces degeneration and reinnervation of sensory nerve fibres.

    Science.gov (United States)

    Ohtori, S; Inoue, G; Mannoji, C; Saisu, T; Takahashi, K; Mitsuhashi, S; Wada, Y; Takahashi, K; Yamagata, M; Moriya, H

    2001-11-23

    There have been several reports on the use of extracorporeal shock waves in the treatment of pseudarthrosis, calcifying tendinitis, and tendinopathies of the elbow. However, the pathomechanism of pain relief has not been clarified. To investigate the analgesic properties of shock wave application, we analyzed whether it produces morphologic changes in cutaneous nerve fibres. In normal rat skin, the epidermis is heavily innervated by nerve fibres immunoreactive for protein gene product (PGP) 9.5 and by some fibres immunoreactive for calcitonin gene-related peptide (CGRP). There was nearly complete degeneration of epidermal nerve fibres in the shock wave-treated skin, as indicated by the loss of immunoreactivity for PGP 9.5 or CGRP. Reinnervation of the epidermis occurred 2 weeks after treatment. These data show that relief of pain after shock wave application to the skin results from rapid degeneration of the intracutaneous nerve fibres.

  13. Computational Models of Material Interfaces for the Study of Extracorporeal Shock Wave Therapy

    CERN Document Server

    Fagnan, Kirsten; Matula, Thomas J

    2012-01-01

    Extracorporeal Shock Wave Therapy (ESWT) is a noninvasive treatment for a variety of musculoskeletal ailments. A shock wave is generated in water and then focused using an acoustic lens or reflector so the energy of the wave is concentrated in a small treatment region where mechanical stimulation enhances healing. In this work we have computationally investigated shock wave propagation in ESWT by solving a Lagrangian form of the isentropic Euler equations in the fluid and linear elasticity in the bone using high-resolution finite volume methods. We solve a full three-dimensional system of equations and use adaptive mesh refinement to concentrate grid cells near the propagating shock. We can model complex bone geometries, the reflection and mode conversion at interfaces, and the the propagation of the resulting shear stresses generated within the bone. We discuss the validity of our simplified model and present results validating this approach.

  14. Turbulent Supernova Shock Waves and the Sterile Neutrino Signature in Megaton Water Detectors

    CERN Document Server

    Choubey, S; Ross, Graham G; Choubey, Sandhya

    2007-01-01

    The signatures of sterile neutrinos in the supernova neutrino signal in megaton water Cerenkov detectors are studied. Time dependent modulation of the neutrino signal emerging from the sharp changes in the oscillation probability due to shock waves is shown to be a smoking gun for the existence of sterile neutrinos. These modulations and indeed the entire neutrino oscillation signal is found to be different for the case with just three active neutrinos and the cases where there are additional sterile species mixed with the active neutrinos. The effect of turbulence is taken into account and it is found that the effect of the shock waves, while modifed, remain significant and measurable. Supernova neutrino signals in water detectors can therefore give unambiguous proof for the existence of sterile neutrinos, the sensitivity extending beyond that for terrestial neutrino experiments. In addition the time dependent modulations in the signal due to shock waves can be used to trace the evolution of the shock wave i...

  15. Effect of shock wave reapplication on urinary n-acetyl-beta-glucosaminidase in canine kidney

    Directory of Open Access Journals (Sweden)

    Marco A.Q.R. Fortes

    2004-04-01

    Full Text Available OBJECTIVE: Renal tubular damage can be assessed with the aid of urinary dosing of N-acetyl-beta-glucosaminidase (NAG and it is possible to demonstrate a significant correlation between shock wave and damage to renal parenchyma. The objective of this study was to assess the effect of shock wave reapplication over urinary NAG in canine kidney. MATERIALS AND METHODS: The authors submitted 10 crossbred dogs to 2 applications of 2000 shock waves in a 24-hour interval in order to assess urinary NAG values after 12, 24, 36 and 48 hours. RESULTS: Twelve hours following the first shockwave application there was an increase in NAG of 6.47 ± 5.44 u/g creatinine (p 0.05. CONCLUSION: Shock wave reapplication with a 24-hour interval did not cause any increase in urinary NAG.

  16. Shock Formation and Energy Dissipation of Slow Magnetosonic Waves in Coronal Plumes

    Science.gov (United States)

    Cuntz, M.; Suess, S. T.

    2003-01-01

    We study the shock formation and energy dissipation of slow magnetosonic waves in coronal plumes. The wave parameters and the spreading function of the plumes as well as the base magnetic field strength are given by empirical constraints mostly from SOHO/UVCS. Our models show that shock formation occurs at low coronal heights, i.e., within 1.3 bun, depending on the model parameters. In addition, following analytical estimates, we show that scale height of energy dissipation by the shocks ranges between 0.15 and 0.45 Rsun. This implies that shock heating by slow magnetosonic waves is relevant at most heights, even though this type of waves is apparently not a solely operating energy supply mechanism.

  17. An LDA investigation of the normal shock wave boundary layer interaction

    Science.gov (United States)

    Chriss, R. M.; Hingst, W. R.; Strazisar, A. J.; Keith, T. G.

    1990-01-01

    Nonintrusive measurements have been made of two normal shock wave-boundary layer interactions. Two-dimensional measurements were made throughout the interaction region while three-dimensional measurements were made in the vicinity of the shock wave. The measurements were made in the corner of the test section of a continuous flow supersonic wind tunnel in which a normal shock wave had been stabilized. LDA, surface pressure measurement and flow visualization techniques were employed for two freestream Mach number test cases: 1.6 and 1.3. The former contained separated flow regions and a system of shock waves. The latter was found to be far less complicated. The reported results define the flowfield structure in detail for each case.

  18. A solid-phase mechanism of shock-wave formation of dust particles of heavy metals

    Science.gov (United States)

    Lin, E. E.; Mikhailov, A. L.; Khvorostin, V. N.

    2016-08-01

    The possibility of formation of dust particles in solid as a result of shock-wave destruction of the initial crystalline material structure and subsequent coalescence of atomic clusters (nanoparticles), which leads to the aggregation of mesocrystalline particles (grains) in the shocked layer, is discussed.

  19. Measurement of scaling laws for shock waves in thermal nonlocal media

    CERN Document Server

    Ghofraniha, N; Folli, V; Trillo, S; DelRe, E; Conti, C

    2012-01-01

    We are able to detect the details of spatial optical collisionless wave-breaking through the high aperture imaging of a beam suffering shock in a fluorescent nonlinear nonlocal thermal medium. This allows us to directly measure how nonlocality and nonlinearity affect the point of shock formation and compare results with numerical simulations.

  20. Towards Low Energy Atrial Defibrillation

    Directory of Open Access Journals (Sweden)

    Philip Walsh

    2015-09-01

    . Efficient transcutaneous power transfer and sensing of ICI during cardioversion are evidenced as key to the advancement of low-energy atrial defibrillation.