The application of immersed boundary-lattice Boltzmann method in vortex-induced vibration

Aiming at vortex-induced vibration problem, immersed boundary-lattice Boltzmann method (IB-LBM) is adopted in the paper. In order to establish a baseline for comparison and verify the precision of the algorithm, a uniform flow past a rigid cylinder at Re=200 is simulated first and the numerical results are compared with the results of other documents. The motion of the elastic-supported cylinder is modelled by a spring-damper-mass system and the motion equation is solved using the Runge-Kutta method. The cylinder is only allowed to vibrate in transverse direction and the Reynolds number is kept at 200. Besides, the lift and drag coefficients of the cylinder, the displacement of the cylinder and the vortex pattern in the wake are extracted at different natural frequencies, and on this basis the dynamic response characteristic of the cylinder is studied. As the natural frequency reduces, the time history of fluctuating hydrodynamic coefficients characterized by 'beating' is presented, and the phase between lift force and the cross-flow displacement undergoes a change from the 'in-phase'mode to the 'out-of-phase' mode. The results further show that the cylinder oscillations could be as large as 0.53 diameter under certain natural frequency.