• Title/Summary/Keyword: impingement distance

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Effects of Mobilization with Movement Combined with Exercise(EMWM) on ADH, ROM and Functional Performance in Patients with Impingement Syndrome of the Shoulder (운동과 MWM을 혼합한 중재(EMWM)가 어깨관절 충돌증후군 환자의 AHD, ROM, 기능수행정도에 미치는 효과)

  • Choo, Yeonki
    • Journal of The Korean Society of Integrative Medicine
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    • v.7 no.2
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    • pp.153-163
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    • 2019
  • Purpose : This study was to identify the effects of Mobilization with Movement combined with exercise (EMWM) on acromio-humeral distance (AHD), range of motion (ROM), pain intensity, and functional performance in patients with impingement syndrome of the shoulder. Methods : The subjects were 40 patients diagnosed with impingement syndrome of the shoulder. Twenty subjects are randomly assigned to each 2 different groups; Group 1. (exercise group), Group 2. (EMWM group). Three weekly interventions were given for 4 weeks. The main outcome measures were ultrasound, goniometer, visual analogue scale (VAS), and Korean Constant shoulder score (K-CSS). The ultrasound (AHD), ROM (flexion, abduction), pain intensity (for shoulder flexion) and functional performance (K-CSS) were compared between the groups. Results : The AHD was significantly increased in Group 2 compared to Groups 1. No significant difference was observed between the groups in the range of abduction of the shoulder, but the range of flexion was significantly increased in Group 2 compared to Groups 1. Pain intensity was significantly lower in Group 2 than in Group 1, and functional performance was significantly increased in Group 2 compared to Group 1. Conclusion : An intervention that combined mobilization with movement with exercise was more effective than exercise alone for rapid recovery from shoulder injury and improvement in functional performance.

Numerical Study on Impingement Process and Fuel Film Formation of GDI Spray according to Wall Geometry under High Ambient Temperature (고온에서 벽면 형상에 따른 GDI 분무의 충돌 과정 및 연료 액막 형성에 대한 수치적 연구)

  • Shim, Young-Sam;Choi, Gyung-Min;Kim, Duck-Jool
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.2
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    • pp.166-174
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    • 2008
  • Numerical study on the impingement process and the fuel film formation of the hollow-cone fuel spray was conducted under vaporization condition, and the effect of the wall cavity angle on spray-wall impingement structure was investigated. A detailed understanding of this phenomena will help in designing injection systems and controlling the strategies to improve engine performance and exhaust emissions of the Gasoline Direct Injection (GDI) engine. The improved Abramzon model was used to model the spray vaporization process and the Gosman model was adopted for modeling of spray-wall impingement process. The calculated results of the spray-wall impingement process were compared with experimental results. The velocity field of the ambient gas, the Sauter Mean Diameter (SMD) and the generated fuel film on the wall, which are difficult to obtain by the experimental method, were also calculated and discussed. It was found that the radial distance after the wall impingement and the SMD decreased with increasing the cavity angle and the temperature.

A NUMERICAL STUDY ON JET IMPINGEMENT OF PULSED PLASMA DISCHARGE ON A FLAT PLATE (벽면에 충돌하는 펄스 플라즈마 제트 유동특성에 대한 수치적 연구)

  • Kim, K.;Kwak, H.S.;Park, J.Y.
    • Journal of computational fluids engineering
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    • v.14 no.1
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    • pp.70-77
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    • 2009
  • In this study, time-dependent numerical analysis was carried out to investigate the plasma jet impingement on a flat plate, and a compressible form of two-dimensional inviscid gas dynamics equations were solved using the flux corrected transport algorithm. The mathematical modeling of Joule heating in the polycarbonate capillary bore and the mass ablation from the bore wall was incorporated in the numerical analysis and the series of computation was performed for three cases depending on the distance of the opposing plate from the capillary exit. The computational results reveal that the presence of the opposing plate does not affect the flow conditions inside the capillary when compared to the case of open-air plasma discharge. In the exterior region, the flow structure shows the typical supersonic underexpanded jet which consists of the strong Mach disk in front of the opposing plate and the barrel shock at the side of the jet. It is found that the shock evolution becomes more quasi-steady when the plate distance decreases. Also, the effects of the distance between the capillary bore exit and the opposing plate on the flow conditions along the opposing plate are investigated and the pressure variation on the plate shows more complicated interaction between the plasma discharge and the opposing plate when the location of plate becomes closer to the capillary exit.

Determination of mass flow rate, jet temperature and heating time in mold surface heating technology using hot jet impingement (고온제트에 의한 금형표면 가열기법에서의 유량, 온도, 가열시간의 결정)

  • Choi, Sung-Ju;Yoo, Young-Eun;Kim, Sun-Kyoung
    • 한국금형공학회:학술대회논문집
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    • 2008.06a
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    • pp.135-139
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    • 2008
  • Development of surface heating technology using hot jet impingement onto mold inner surface for improvement of pattern transcription. This study is focused on how to control the parameters related to hot jet impingement. The mass flow rate, the jet temperature and the duration of the impingement are major parameters. The nozzle design and other geometric configurations also affect the heat transfer to the surface. In terms of heat transfer analysis, the most important number is the heat transfer coefficient, which is influenced by the mass flow rate, nozzle design, distance between the nozzle tip and the surface. In summary, several parametric studies using the developed model are conducted to investigate the effects of mass flow rate, jet temperature and Heating Time in Surface heating technology using hot jet impingement onto mold.

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Heat/mass transfer characteristics of arrays of impingement jets using effusion holes (유출홀을 사용한 배열충돌제트의 열/물질전달 특성)

  • Yoon, P.H.;Hwang, S.D.;Cho, H.H.
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.125-131
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    • 2000
  • The local heat/mass transfer coefficients for arrays of impinging circular air jets on a plane surface are determined by means of the naphthalene sublimation method. Spent fluid makes a crossflow in the confined space. The crossflow reduces heat/mass transfer at the small gap distance between the jet plate and impingement surface because of reentrainment of the spent fluid. The present study suggests a new exhaust system having effusion holes in the impinging jet plate. The spent air flow out after impingement just through effusion holes located in the upper plate. This system increases heat/mass transfer coefficients and uniformity for small gap distances$(H/d{\leq}2)$

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Turbulent Flow Characteristics using Plane Jet on Impingement Surface (평면제트를 이용한 충돌면에서의 난류유동 특성)

  • 윤순현
    • Journal of Advanced Marine Engineering and Technology
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    • v.22 no.4
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    • pp.429-435
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    • 1998
  • Experiments were conducted to investigate the turbulent flow characteristics from on oblique impingement surface to an plane jet at the jet Reynolds number(Re based on the nozzle width) $3{\times}10^4$ The jet mean velocity and turbulent intensity profiles have been measured along the impingement surface by hot-wire anemometer. The nozzle-to-plate distance(H/B) ranged from 2 to 10 and the oblique angle (a) from 45 to 90 degree. Also the secondary peak of the turbulent intensity was observed at H/B=4 S/B 5 and a=90 degree. It has been found that the stagnation point shifted toward the minor flow region as the oblique angle decreased and the position of the stagnation point nearly coincided with that of the maximum turbulent intensity.

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Characteristics of Supersonic Jet Impingement on a Flat Plate (평판에 충돌하는 초음속 제트에 유동특성)

  • Hong Seung-kyu;Lee Kwang-Seop;Park Seung-O
    • Journal of computational fluids engineering
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    • v.6 no.3
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    • pp.32-40
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    • 2001
  • Viscous solutions of supersonic jet impinging on a flat plate normal to the flow are simulated using three-dimensional Navier-Stokes solver. The jet impinging flow structure exhibits such complex nature as shock shell, plate shock and Mach disk depending on the flow parameters. Among others, the dominant parameters are the ratio of the nozzle exit pressure to the ambient pressure and the distance between the nozzle exit plane and the impinging plane. In the present study, the nozzle contour and the pressure ratio are held fixed, while the jet impinging distance is varied to illuminate the characteristics of the jet plume with the distance. As the plate is placed close to the nozzle at 3D high, the computed wall pressure at or near the jet center oscillates with large amplitude with respect to the mean value. Here D is the nozzle exit diameter. The amplitude of wall pressure fluctuations subsides as the distance increases, but the maximum mean pressure level at the plate is achieved when the distance is about 4D high. The frequency of the wall pressure is estimated at 6.0 kHz, 9.3 kHz, and 10.0 kHz as the impinging distance varies from 3D, 4D, to 6D, respectively.

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An Experimental Study on Heat Transfer and Fluid Flow on the Semi-Circular Concave Surface Cooled by Jet Impingement (제트충돌냉각되는 반원 오목면에서 열전달 및 유체유동에 관한 실험적 연구)

  • Yu, Han-Seong;Yang, Geun-Yeong;Lee, Jun-Sik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.20 no.9
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    • pp.2991-3006
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    • 1996
  • An experimental study of jet flow and heat transfer has been carried out for the jet impingement cooling on a semi-circular concave surface. For the jet impingement on the concave surface, three different regions-free jet region, stagnation region, and wall jet flow region-exist, and the distributions of mean velocity and fluctuating velocity for each region have been measured by Laser Doppler Velocimeter. Of particular interests are the effects of jet Reynolds number, the distance between the nozzle exit and cooling surface apex, and the distance from the stagnation point in the circumferential direction. The resulting characteristics of heat transfer at the stagnation point and the variation of heat transfer along the circumferential direction including the existence of secondary peak have been explained in conjunction with measured impinge jet flow.

An experimental study on the impingement spray of a common-rail diesel injector (2) -atomization characteristics- (커먼레일식 디젤 인젝터의 충돌 분무에 대한 실험적 연구(2) -미립화 특성-)

  • Lee, C.S.;Park, S.W.;Seo, S.H.
    • Journal of ILASS-Korea
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    • v.8 no.3
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    • pp.19-26
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    • 2003
  • In this study, experimental study on atomization characteristics of the fuel spray impinging on the wall was at different wall distances and angles of wall inclination. The fuel injection system was composed based on the common rail system. and the injection signal was synchronized by the delay generator. The atomization characteristics of the injected spray were analyzed in terms of the SMD and velocities which were measured by using the phase Doppler particle analyzer system. It is revealed that the free spray is atomized actively above 50mm form the injector tip. In the cases of the impinged spray, the 5MD and velocity of the impinged spray are smaller than those of the free spray. The impinged spray has the maximum near the 35mm of the radial distance from the injector axis, and the atomization performance is enhanced with the decrease of the wall distance.

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An Experimental Study of Jet Impingement Cooling on the Semi-Circular Concave Surface (반원 오목면에 분사되는 제트충돌 냉각에 관한 실험적 연구)

  • 양근영;최만수;이준식
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.4
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    • pp.1083-1094
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    • 1995
  • An experimental study has been carried out for jet-impingement cooling on the semi-circular concave surface. Two different nozzles(round edged nozzle and rectangular edged nozzle) are utilized and heat transfer coefficients on the concave surface have been measured under a constant heat flux condition. The characteristics of heat transfer has been discussed in conjunction with measured jet flow. Velocity and turbulence intensity of free jets issuing from two different nozzles have been measured by Laser Doppler Anemometry and theromocouple measurements have been done for temperatures on the concave surface. The effects of the nozzle shape, the distance between the nozzle exit and the stagnation point of the surface and the nozzle exit velocity on heat transfer were studied.