Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Numerical Study on the Characteristics of Fluid Flow and Pressure Fluctuation around Human Knuckle in Hydrogymnastics

수중 운동 시 손관절 부위의 유동 및 압력변동 특성에 대한 해석적 연구

  • Choi, Ji-Hyun (Department of Mechanical Engineering, Graduate School, Kongju National University) ;
  • Park, Sung-Young (Div. of Mechanical & Automative Engineering, Kongju National University)
  • 최지현 (공주대학교 일반대학원 기계공학과) ;
  • 박성영 (공주대학교 기계자동차공학부)
  • Received : 2019.03.27
  • Accepted : 2019.06.07
  • Published : 2019.06.30
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Abstract

Hydrogymnastics so that sufficient exercise effect can be obtained using the resistance of water has a positive effect on patients who have to receive arthritis or rehabilitation treatment. However, the studies on the effect are insufficient, and the main cause of their effects has not been unclear yet. In this study, in order to identify the main cause of the effects of Hydrogymnastics, conducted Unsteady fluid flow simulation under the same conditions as the actual environment. The analysis model based on real hands, and the pressure fluctuation applied to the knuckle was analyzed by the computational fluid method. During the underwater movement of the hands, Various sizes of vortices were generated between fingers due to skin surface velocity and flow resistance. Pressure of about -500 Pa to +500 Pa is applied by the vortex flow. Also It was confirmed that the positive pressure and the negative pressure were continuously repeated up to maximum + 2000 Pa at the minimum of -2000 Pa at the portion where the direction was changed. Pressure fluctuations with a frequency of 20 Hz to 70 Hz were added continuously for each knuckle. These continuous pressure fluctuations provide a direct massage effect on the knuckles, an It is judged that the blood circulation at the relevant part is positively affected.

수중운동치료는 물의 저항을 이용하여 충분한 운동 효과를 낼 수 있어서 관절염이나 재활치료를 받아야하는 환자들에게 긍정적인 효과를 가진다. 하지만 효과에 대한 국내 연구는 미비한 실정이고, 그 효과에 대한 근본적인 원인규명은 아직까지 확실하지 않다. 따라서 본 연구에서는 수중운동 효과의 근본적인 원인을 파악하기 위해 실제 환경과 비슷한 조건으로 Unsteady fluid flow simulation을 진행했다. 해석 모델은 실제 손을 모델링하였고, 손가락 마디에 가해지는 압력변동을 the methods of computational fluid로 분석했다. 손의 수중운동 시, 피부 표면속도와 유동 저항에 의하여 손가락 사이에 다양한 크기의 와류가 발생한다. 와류에 의해 약 -500Pa부터 +500Pa 정도의 압력이 가해지고, 방향을 전환하는 부분에서는 최소 -2000Pa에서 최대 +2000Pa까지의 양압과 음압이 지속적으로 반복됐다. 또한 손가락 마디마다 20Hz ~ 70Hz의 진동수를 가진 압력 변동이 지속적으로 가해졌다. 이러한 지속적인 압력 변동은 손가락 마디에 직접적인 마사지 효과를 제공하고, 관련 부위의 혈액순환에 긍정적인 영향을 미친다고 판단된다.

Keywords

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Fig. 1. 3D-model of upper limb

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Fig. 2. moving profile depends on position

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Fig. 3. Pressure measurement position

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Fig. 4. Velocity Magnitude field

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Fig. 5. Wall Shear Stress

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Fig. 6. Frequency position for each finger

Table 1. Mesh setting for Arm aquatic excercis

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References

  1. D. W. Han, Effects of Aqua Exercise Program on the Improvement of Physical Function, Body Compositions and Blood Components in the Older Adults, Ph.D dissertation, Daegu University, Daegu, Korea, 2002.
  2. S. M. Nam, (The)effects of underwater activity utilizing buoyancy aids on the foot sole pressure of the patients with hemiplegia, Master's thesis, Yongin University, Gyeonggi Province, Korea, 2010.
  3. T. Y. Kim, G. Y. Kim, J. Lambeck, "Hydrotherapy in Rheumatoid Arthritis", The Journal of Korean Society of Physical Therapy, Vol.12, No.3, pp.407-414, 2000.
  4. J. A. Adsett, A. M. Mudge, N. Morris, S. Kuys, J. D. Paratz, "Aquatic exercise training and stable heart failure: A systematic review and meta-analysis", International Journal of Cardiology, Vol.186, No.1, PP.22-28, May. 2015. DOI: http://dx.doi.org/10.1016/j.ijcard.2015.03.095
  5. L. Costa, V. R. Mantha, A. J. Silva, R. J. Fernandes, D. A. Marinho, et al, "Computational fluid dynamics vs. inverse dynamics methods to determine passive drag in two breaststroke glide positions", journal of Biomechanics, Vol.48, No.10, pp.2221-2226, July. 2015. DOI: https://doi.org/10.1016/j.jbiomech.2015.03.005
  6. K. S. Hyun, The effects of rehabilitation exercise programs on muscular function and body composition of anterior cruciate ligament reconstruction surgery patients, Ph.D dissertation, Korea University, Seoul, Korea, 2000.
  7. J. I. Kim, K. S. Cho, H. S. Sim, E. N. Lee, I. O. Lee, Y. Eun, D. S. Lee, H. S. Kang, W. S. Bak, J. H. Lee, "Analysis of Studies on the Effect of Aquatic Exercise Program", The Journal of Muscle and Joint Health, Vol.18, No.2, pp.257-269, November, 2011. DOI: https://doi.org/10.5953/JMJH.2011.18.2.257
  8. G. Caminiti, M. Volterrani, G. Marazzi, A. Cerrito, R. Massaro, et al., "Hydrotherapy added to endurance training versus endurance training alone in elderly patients with chronic heart failure: a randomized pilot study", Internation Journal of Cardiology, Vol.148, No.2, pp.199-203, April.. 2011. DOI: https://doi.org/10.1016/j.ijcard.2009.09.565
  9. M. G. Neto, C. S. Conicao, F. L. Arcanjo de jesus, V. O. Carvalho, "Hydrotherapy on exercise capacity, muscle strength and quality of life in patients with heart failure: A meta-analysis", International Journal of Cardiology, Vol.198, No.1, pp.216-219, November. 2015. DOI: http://dx.doi.org/10.1016/j.ijcard.2014.10.132
  10. S. I. Lee, S. Y. Park, "Numerical analysis of internnal flow characteristics of urea injectors for SCR dosing system", Fuel, Vol.129, No.1, pp.54-60, August. 2014. DOI: https://doi.org/10.1016/j.fuel.2014.03.031
  11. C. S. Kim, S. Y. Park, "COMPUTATIONAL STUDY ON THE CHARACTERISTICS OF THE MASS FLOW RATE OF A UREA-SCR INJECTOR WITH VARIOUS NEEDLE PROFILES", Advances and Application in Fluid Mechanics, Vol.19, No.4, pp.867-877, October. 2016. DOI: http://dx.doi.org/10.17654/FM019040867
  12. C. S. Kim, S. Y. Park, "COMPUTATIONAL ANALYSIS OF THE TRANSIENT INTERNAL FLOW CHARACTERISTICS OF A THREE-HOLE UREA-SCR INJECTOR FOR COMMERCIAL VEHICLES", Advances and Application in Fluid Mechanics, Vol.19, No.4, pp.903-912, October. 2016. DOI: http://dx.doi.org/10.17654/FM019040903
  13. C. S. Kim, S. Y. Park, "A Design-Variable-Based Computational Study on the Unsteady Internal-Flow Characteristics of the Urea-SCR Injector for Commercial Vehicles", Defect and Diffusion Forumm, Vol.379, pp.64-72, Nobemver. 2017. DOI: https://doi.org/10.4028/www.scientific.net/DDF.379.64
  14. E. J. Gwak, S. Y. Park, "Study on the flow Characteristics of the Urea-SCR Swirl injector Using the Unsteady CFD Technique", Journal of Engineering and Applied Sciences, Vol.13, No.2, pp.2978-2985, 2018.
  15. CD-Adapco, Star-CCM+ ver. 11.04 User Guide, 2016.
  16. J. I. Kim, K. H. Choi, S. Y. Park, "Computation Fluid Flow Study on the pressure Fluctuation Caused by the Vortex Flow Arising From Underwater Exercises of Arthritis Patient", Defect and Diffusion Forum, Vol. 390, pp.8-22, 2019. DOI: https://doi.org/10.4028/www.scientific.net/DDF.390.8