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An experimental study on the flow characteristics around to changes in the angle of the wedge type structure by free fall

자유낙하에 의한 각도 변화에 따른 쐐기형 구조물 주위의 유동특성에 관한 실험적 연구

  • Oh, Seung-Jin (Division of Marine Engineering, Graduate School, Mokpo National Maritime University) ;
  • Cho, Dae-Hwan (Faculty of Marine Engineering, Mokpo National Maritime University)
  • Received : 2013.03.26
  • Accepted : 2013.07.11
  • Published : 2013.07.31

Abstract

This paper presents are experimental investigation to figure out impact pressure and flow characteristics of a wedge type structure in free fall. The flow field has been obtained by 2-frame grey level cross correlation PIV(Particle Image Velocimetry) method, the impact pressure of free fall structure by a pressure acquisition system apply to Dewetron system. The angles between a model and the free surface are adapted $15^{\circ}$, $25^{\circ}$, $35^{\circ}$ and $45^{\circ}$ respectively. Velocity field of water exit has higher better than water entry. The impact pressure under the bottom of the model has been appeared higher values at $15^{\circ}$ than $45^{\circ}$, and also at P1.

본 연구에서는 자유낙하 하는 쐐기형 구조물의 각도 변화에 따른 충격압력 및 유동특성을 알아보고자 실험을 수행하였다. 유동장의 계측은 2-프레임 그레이레벨 상호상관 PIV기법을 이용하였으며, 충격압력의 계측은 압력계측장비인 Dewetron System을 이용하였다. 모델과 자유수면이 이루는 각도는 $15^{\circ}$, $25^{\circ}$, $35^{\circ}$$45^{\circ}$를 적용하여 다양성을 주어 실험하였으며, 속도장은 접수보다 이수에서 빠른 유동특성을 나타냈으며, 접수에서 보다 이수에서 시간이 더 소요됨을 보였다. 모델 하부에서의 충격압력은 쐐기의 각도 $45^{\circ}$ 보다, 입수각이 작은 $15^{\circ}$와 P1 지점에서 높게 나타났다.

Keywords

References

  1. Park and Chun, "Analysis of flow around a rigid body on water-entry & exit problems", Journal of the Society of Naval Architects of Korea, vol. 36, no. 4, pp. 37-47, 1999.
  2. Lee, J. and Philip A. W., "Experimental study of the hydro-impact of slamming in a modern racing sailboat", Journal of Sailboat Technology, article 2010-01, pp. 1-29, 2010.
  3. Baker, G. S. and Keary, E. M.. Experiments with Full-Sized Machines, British A.R.C. Reports and Memoranda No 683, pp. 1-10, 1920.
  4. Von Karman, T., The Impact of Seaplane Floats during Landing, N.A.C.A. TN321 Washington, pp. 1-8, 1929.
  5. Lee, Rim, Kim, Hea and Kim, "A study on measurement of flare slamming of large container vessel(II) Characteristic analysis of measured slamming pressure", Journal of the Society of Naval Architects of Korea, vol. 44, no. 3, pp. 279-284, 2007. https://doi.org/10.3744/SNAK.2007.44.3.279
  6. Lee and Cho, "A study on PIV measurement of unsteady flow around disk caused by slide type valve quick closing", Journal of the Korean Society of Marine Environment & Safety vol. 15, no. 3, pp. 251-256, 2009.
  7. Park, Lee and Rim, "Whipping analysis of hull girders considering slamming impact loads", Journal of the Society of Naval Architects of Korea vol. 37, no. 3, pp. 99-109, 2000.