Study on Prolate Spheroid Pitching Oscillation in Viscous Stratified Flow

XIONG Ying; GUAN Hui; WU Chuijie

doi:10.21656/1000-0887.390041

Volume 39 Issue 8

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XIONG Ying, GUAN Hui, WU Chuijie. Study on Prolate Spheroid Pitching Oscillation in Viscous Stratified Flow[J]. Applied Mathematics and Mechanics, 2018, 39(8): 900-912. doi: 10.21656/1000-0887.390041

Citation:

XIONG Ying, GUAN Hui, WU Chuijie. Study on Prolate Spheroid Pitching Oscillation in Viscous Stratified Flow[J]. Applied Mathematics and Mechanics, 2018, 39(8): 900-912. doi: 10.21656/1000-0887.390041

Citation:

XIONG Ying, GUAN Hui, WU Chuijie. Study on Prolate Spheroid Pitching Oscillation in Viscous Stratified Flow[J]. Applied Mathematics and Mechanics, 2018, 39(8): 900-912. doi: 10.21656/1000-0887.390041

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Study on Prolate Spheroid Pitching Oscillation in Viscous Stratified Flow

doi: 10.21656/1000-0887.390041

¹Unit 91550 of PLA, Dalian, Liaoning 116023, P.R.China;²College of Meteorology and Oceanography, National University of Defense Technology, Nanjing 211101, P.R.China;³School of Aeronautics and Astronautics, Dalian University of Technology, Dalian, Liaoning 112024, P.R.China

Funds: The National Natural Science Foundation of China(11572350;11372068);The National Basic Research Program of China(973 Program)(2014CB-744104)

Received Date: 2018-01-24
Rev Recd Date: 2018-05-25
Publish Date: 2018-08-15

Abstract

Abstract

The numerical calculation model for the continuous stratified flow was established through the study on the decaying process of the free pitching oscillation of the prolate spheroid in viscous stratified flow. The correctness of the numerical model was verified through numerical simulation of the viscous flow field of a sphere and calculation of its increasing drag coefficient. Under the 45° prolate spheroid initial angle the pitching oscillation process was investigated, with the Aitken sub-relaxation self-adaptive algorithm-based 2-way fluid-solid coupling method, and numerical simulation of the flow field around the prolate spheroid in pitching decaying oscillation at different values of Froude number Fr_i was performed. The numerical results show that, the pitching up and down agitates the surrounding fluid, and forms 4 symmetric density vortex rings on both sides of the prolate spheroid; the vertical density stratification limits vertical propagation of the vortex rings and accelerates disappearance of the vortex rings, and this limitation contributes to the development of horizontal motion. At higher Fr_i and Reynolds number Re,the 2-way coupling method suppresses numerical oscillations. The research also finds that, with the increase of the incoming velocity, the drag coefficient decreases, which means that for the prolate spheroid with free pitching oscillation, the phenomenon of negative drag still appears.
- viscous stratified flow,
- prolate spheroid,
- free decaying,
- pitching oscillation

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References(11)

References

[1]	NEWMAN J N. The damping of an oscillating ellipsoid near a free surface[J]. Ship Research,1961,5(3): 44-58.
[2]	LOFQUIST K K, PURTELL L P. Drag on a sphere moving horizontally through a stratified liquid[J]. Journal of Fluid Mechanics,1984,148(1): 271-284.
[3]	GREENSLADE M D. Drag on a sphere moving horizontally in a stratified fluid[J]. Journal of Fluid Mechanics,2000,418: 339-350.
[4]	STUROVA I V. Radiation instability of a circular cylinder in a uniform flow of a two-layer fluid[J]. Journal of Applied Mathematics and Mechanics,1997,61(6): 957-965.
[5]	GUSHCHIN V A, MITKIN V V, ROZHDESTVENSKAYA T I, et al. Numerical and experimental study of the fine structure of a stratified fluid flow over a circular cylinder[J]. Journal of Applied Mechanics and Technical Physics,2007,48(1): 34-43.
[6]	MENTER F R, KUNTZ M, LANGTRY R. Ten years of industrial experience with the SST turbulence model[J]. Turbulence Heat and Mass Transfer,2003,4(1): 625-632.
[7]	XIONG Ying, GUAN Hui, WU Chuijie. Unsteady analysis of six-DOF motion of a 6∶1 prolate spheroid in viscous fluid[J]. Science China (Physics, Mechanics & Astronomy),2017,60(11): 114711. DOI: 10.1007/s11433-017-9071-y.
[8]	RHIE C M, CHOW W L. Numerical study of the turbulent flow past an airfoil with trailing edge separation[J].AIAA Journal,1983,21(11): 1525-1532.
[9]	熊英, 关晖, 吴锤结. 基于有限体积法的非结构网格大涡模拟离散方法研究[J]. 应用数学和力学, 2016,37(11): 1129-1144.(XIONG Ying, GUAN Hui, WU Chuijie. LES discretization methods for unstructured meshes based on the finite volume method[J]. Applied Mathematics and Mechanics,2016,37(11): 1129-1144.(in Chinese))
[10]	SSA R I. Solution of the implicitly discretised fluid flow equations by operator-splitting[J]. Journal of Computational Physics,1986,62(1): 40-65.
[11]	JIANG F, GALLARDO J P, ANDERSSON H I. The laminar wake behind a 6∶1 prolate spheroid at 45° incidence angle[J].Physics of Fluids,2014,26(11): 1044-1050.