Flow Induced Vibration Of An Elliptic Cylinder At Low Reynolds Number

It is found that sea lions keep their whiskers almost constant as they are swimming.This guarantees that sea lions can pick up the signal of the upstream target with reduced background noise.In engineering applications,such as heat exchangers and nuclear reactors,which contain many tubes and rod bundles,would suffer destructive vibration with small amplitude.Inspired by the whiskers of sea lions,some kinds of methods are explored to reduce the vibration of cylindrical structures.In the present study,the sea lions'whiskers are modeled as the elliptic cylinder and the effects of angle of attack???,aspect ratio?AR?and reduced velocity?U_r?are investigated on flow-induced vibration of an elliptical cylinder at low Reynolds number?Re?.In the present study,the finite volume method is used to investigate the effect of reduced velocity?U_r?on the structure's vibration.The reduced velocity?U_r?is changed by the natural frequency f_n of the elliptical cylinder at Re=100 and mass ratio m*=10.Meanwhile,the effect of?and AR on the structure's vibration are investigated.Vibration amplitudes A_x,A_y,added mass m_a,fluctuating drag coefficient C'_D and lift coefficient C'_L are discussed at the different angles of attack???,aspect ratios?AR?and reduced velocities?U_r?of the elliptic cylinder.Through the systematic study,the following conclusions are summarized:?1?A_x,A_y decrease with the decrease AR.?2?Before the lock-in region,m_a*has a large value,and decrease with increasing U_r.But m_a*keeps stable in the lock-in range.?3?The angle of attack has a significant influence on vibration.The lock-in phenomena appears at smaller U_r for the range of?=0°-90°.?4?Three vortex shedding modes are found in the present study,i.e.,2S,C?2S?and P+S.It is observed,at?=0°the vortex shedding mode switch between the modes 2S and C?2S?.The vortex shedding modes P+S appears for ??0°.