• Title/Summary/Keyword: shock wave theory

Search Result 56, Processing Time 0.029 seconds

A Literature Review on the Use of Extracorporeal Shock Wave with Syndrome Differentiation Theory (한방 변증 이론에 근거하여 사용된 체외충격파 연구에 대한 문헌 고찰)

  • Lee, Sang-Hyun;Kim, Hyun-Tae;Park, Sun-Young;Heo, In;Hwang, Man-Suk;Shin, Byung-Cheul;Hwang, Eui-Hyoung
    • Journal of Korean Medicine Rehabilitation
    • /
    • v.30 no.2
    • /
    • pp.95-103
    • /
    • 2020
  • Objectives This report aimed to review literatures using extracorporeal shock wave with syndrome differentiation theory. Methods By March 3, 2020, five foreign electronic databases (PubMed, Web of Science, Cochrane Library, EMBASE, CAJ) and six Korean medical electronic databases (KMBASE, KISTI, KISS, NDSL, DBpia, RISS) were reviewed with the key word 'extracorporeal shock wave' and 'syndrome differentiation'. We did not impose restrictions on age, gender, treatment methods, duration, results and the design of the paper. Results Twelve papers met the inclusion criteria. Seven papers used extracorporeal shock wave lithotripsy with syndrome differentiation theory and six out of seven papers treated urologic stones using extracorporeal shock wave lithotripsy. The other five papers used extracorporeal shock wave therapy with syndrome differentiation theory and four of them treated musculoskeletal disorders. However, the data of the characteristics of extracorporeal shock wave was insufficient. Conclusions After thorough review, it is considered to be meaningful to treat urologic stones and musculoskeletal disorders using extercorporeal shock wave with syndrome differentiation theory. However, some of the literatures were limited in their feasibility and reliability in terms of research design. In addition, the data regarding the strength of the extracorporeal shock wave applied on each acupoints was insufficient. Therefore, further study on the use of extracorporeal shock wave on acupoints should be conducted.

LARGE AMPLITUDE THEORY OF A SHOCK-ACCELERATED INSTABILITY IN COMPRESSIBLE FLUIDS

  • Sohn, Sung-Ik
    • Korean Journal of Mathematics
    • /
    • v.19 no.2
    • /
    • pp.191-203
    • /
    • 2011
  • The interface between fluids of different densities is unstable under acceleration by a shock wave. A previous small amplitude linear theory for the compressible Euler equation failed to provide a quantitatively correct prediction for the growth rate of the unstable interface. In this paper, to include dominant nonlinear effects in a large amplitude regime, we present high-order perturbation equations of the Euler equation, and boundary conditions for the contact interface and shock waves.

Shock-Fitting in Kinematic Wave Modeling (운동파 이론의 충격파 처리기법)

  • Park, Mun-Hyeong;Choe, Seong-Uk;Heo, Jun-Haeng;Jo, Won-Cheol
    • Journal of Korea Water Resources Association
    • /
    • v.32 no.2
    • /
    • pp.185-195
    • /
    • 1999
  • The finite difference method and the method of characteristics are frequently used for the numerical analysis of kinematic wave model. Truncation errors cause the peak discharge dissipated in the solution from the finite difference method. The peak discharge is conserved in the solution from the finite difference method. The peak discharge is conserved in the solution from the method of characteristics, however, the shock may deteriorates the numerical solution. In this paper, distinctive features of each scheme are investigated for the numerical analysis of kinematic wave model, and applicability of shock fitting algorithm such as Propagating Shock Fitting and Approximated Shock Fitting methods are studied. Propagating Shock Fitting method appears to treat shock properly, however, it failed to fit the shock appropriately when applied to a sudden inflow change in a long river. Approximate Shock Sitting method, which uses finer elements, is found to be more proper shock-fitting than the Propagating Shock Fitting method. Comparisons are made between two solution from the kinematic wave theory with shock fitting and full dynamic wave theory, and the results are discussed.

  • PDF

Mechanisms of Oblique Shock-Induced Combustion Instability

  • Choi, Jeong-Yeol;Jeung, In-Seuck
    • Journal of the Korean Society of Combustion
    • /
    • v.7 no.1
    • /
    • pp.23-30
    • /
    • 2002
  • Instability of oblique detonation waves (ODW) at off-attaching condition was investigated through a series of numerical simulations. Two-dimensional wedge of finite length was considered in $H_2/O_2/N_2$ mixtures at superdetonative condition. Numerical simulation was carried out with a compressible fluid dynamics code and a detailed hydrogen-oxygen combustion mechanism. Present result reveals that there is a chemical kinetic limit of the ODW detachment, in addition to the theoretical limit predicted by Rankine-Hugoniot theory with equilibrium chemistry. Result also presents that ODW still attaches at a wedge as an oblique shock-induced flame showing periodically unstable motion, if the Rankine-Hugoniot limit of detachment is satisfied but the chemical kinetic limit is not. Mechanism of the periodic instability is considered as interactions of shock and reaction waves coupled with chemical kinetic effects. From the investigation of characteristic chemical time, condition of the periodic instability is identified as follows; at the detaching condition of the Rankine-Hugoniot theory, (1) flow residence time is smaller than the chemical characteristic time, behind the detached shock wave with heat addition, (2) flow residence time should be greater than the chemical characteristic time, behind an oblique shock wave without heat addition.

  • PDF

An Analysis of Flow Phenomena in Shock Tube System Design(I)-Comparison of Experimental and Computation Result- (충격파관 장치설계를 위한 유동현상의 해석(1)-계산치와 실험치의 비교-)

  • 정진도;수곡행부
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.5
    • /
    • pp.1218-1226
    • /
    • 1994
  • The shock tube is a useful device for investigating shock phenomena, spray combustion, unsteady gas dynamics, etc. Therefore, it is necessary to analyze exactly the flow phenomena in shock tube. In this study, the mechanics of its reflected shock zone has been investigated by using of the one-dimensional gas dynamic theory in order to estimate the transition from initial reflection of shock wave region. Calulation for four kinds of reflected shock tube temperature (i.e. (a) 1388 K (b) 1276 K (c) 1168 K (d) 1073 K) corresponding to the experimental conditions have been carried out sumarized as follows. (1) The qualitative tendency is almost the same as in that conditions in region of reflected wave region. (2) High temperature period (reflected shock wave temperature) $T_{5}$, exists 0-2.65 ms. (3) Transition period from temperature of reflection shock wave is far longer than the calculated one. This principally attributed to the fact that the contact surface is accelerated, also, due to the release of energy by viscoity effect. This apparatus can advance the ignition process of a spray in a ideal condition that involved neither atomization nor turbulent mixing process, where, using a shock tube, a column of droplets freely from atomizer was ignited behind a reflected shock.

Numerical Study of Sound Generation Mechanism by a Blast Wave (폭발파에 의한 음향파 생성 메커니즘의 수치적 연구)

  • Bin, Jong-Hoon
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.19 no.10
    • /
    • pp.1053-1061
    • /
    • 2009
  • The goal of this paper is to investigate the generation characteristics of the main impulsive noise sources generated by the supersonic flow discharging from a muzzle. For this, this paper investigates two fundamental mechanisms to sound generation in shocked flows: shock motion and shock deformation. Shock motion is modeled numerically by examining the interaction of a sound wave with a shock. The numerical approach is validated by comparison with results obtained by linear theory for a small disturbance case. Shock deformations are modeled numerically by examining the interaction of a vortex ring with a blast wave. A numerical approach of a dispersion-relation-preserving(DRP) scheme is used to investigate the sound generation and propagation by their interactions in near-field.

Computational and Analytical Studies on the Impulse Wave Discharged from the Exit of a Pipe (관출구로부터 방출하는 펄스파에 대한 수치계산과 해석적 연구)

  • Lee, D.H.;Kim, H.S.;Kim, H.D.
    • Proceedings of the KSME Conference
    • /
    • 2001.11b
    • /
    • pp.432-437
    • /
    • 2001
  • A computational work of the impulse wave which is discharged from the open end of a pipe is compared to the Lighthill's aeroacoustics theory. The second-order total variation diminishing(TVD) scheme is employed to solve the axisymmetric, compressible, unsteady Euler equations. The relationship between the initial compressure wave form and the resulting impulse wave is characterized in terms of the peak pressure. The overpressure, pressure gradient and wavelength of the initial compression wave are changed to investigate the influence of the initial compressure wave form on the peak pressure of impulse wave. The results obtained show that for the initial compression wave of a large wavelength and small pressure gradient the peak pressure of the impulse wave depends upon the wavelength and pressure gradient of compression wave, but for the initial compression wave of a short wavelength and large pressure gradient the peak pressure of the impulse wave is almost constant regardless of the wavelength and pressure gradient of compression wave. The peak pressure of the impulse wave is increased with an increase in the overpressure of the initial compression wave. The results from the numerical analysis are well compared to the results from the aeroacoutics theory with a good agreement.

  • PDF

A Study on the Characteristics of the Impulse Wave Discharged from the Exit of a Pipe (관출구로부터 방출하는 펄스파 특성에 관한 연구)

  • 이동훈;김희동;이명호;박종호
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.12 no.1
    • /
    • pp.48-56
    • /
    • 2002
  • A computational work of the impulse wave which is discharged from the open end of a pipe is compared to the Lighthill\`s aeroacoustics theory. The second-order total variation diminishing(TVD) scheme is employed to solve the axisymmetric, compressible, unsteady Euler equations. The relationship between the initial compressure wave form and the resulting impulse wave is characterized in terms of the peak pressure. The overpressure, pressure gradient and wavelength of the initial compression wave are changed to investigate the influence of the initial compressure wave form on the peak pressure of impulse wave. The results obtained show that for the initial compression wave of a large wavelength and small pressure gradient the peak pressure of the impulse wave depends upon the wavelength and pressure gradient of compression wave, but for the initial compression wave of a short wavelength and large pressure gradient the peak pressure of the impulse wave is almost constant regardless of the wavelength and pressure gradient of compression wave. The peak pressure of the impulse wave is increased with an increase in the overpressure of the initial compression wave. The results from the numerical ana1ysis are well compared to the results from the aeroacoutics theory with a food agreement.

A Study on High Velocity Impact Phenomena by a Long Rod Penetrator (긴 관통자에 의한 고속충돌현상 연구)

  • 이창현;최준홍;홍성인
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.3
    • /
    • pp.573-583
    • /
    • 1994
  • In this study, the shock characteristics for high velocity impact phenomena during the initial shock state by the long rod penetrator are calculated. From these results we re-analyze the one-dimensional hydrodynamic penetration theory by introducing the effective area ratio calculated from the mushroomed strain which is dependent on impact velocity. Calculated penetration depth and mushroomed strain show good agreement with high velocity impact experimental data. In addition we visualize the shock wave propagation in a transparent acryle block.

Literature Review and Applicability of Extracorporeal Shock Wave with Meridian and Acupoint Theory (경혈 경락 이론에 근거하여 사용된 체외 충격파 문헌 검색 및 활용 가능성 연구)

  • Jong-Hyeog, Jeong;Yoon-A, Kim;Sang-Hyun, Lee;Byung-Jun, Kim;Eui-Hyoung, Hwang
    • Journal of Physiology & Pathology in Korean Medicine
    • /
    • v.36 no.6
    • /
    • pp.213-220
    • /
    • 2022
  • We investigated the current status of research using extracorporeal shock waves on the basis of meridian and acupoint theory. By March 2022, five foreign databases (CAJ, Pubmed, Web of Science, EMBASE, Cochrane Library) and six Korean databases (Dbpia, RISS, KMBASE, scienceON, KISS, NDSL) were searched with the terms using 'Extracorporeal shock wave' and '(Acupoint or Acupuncture point)'. The search terms were adapted according to the language of the database. There were no restrictions on the study design. As a result of the search, twenty-seven papers were selected for analysis. One study was searched in English database, and the remaining twenty-six studies were searched in Chinese database. There were nineteen pain-related diseases, four obsterics and gynecology diseases, two bone-related diseases, and two other diseases. The most frequently used acupoints were GB34, ST36, and KI3. A total of six adverse events were reported in five papers. The use of extracorporeal shock wave on the basis of meridian and acupoint theory is considered to have sufficient meaning in Korean Medicine. It is expected to use extracorporeal shock wave as a new treatment method for Korean Medicine doctors in the near future.