Numerical Experiment of Flow Around a Two-Dimensional Self-Oscillating Circular Cylinder with Whirling Limitation by a Vortex Method with Boundary Layer Calculation

Abstract

In this study, a numerical experiment of flow around a self-oscillating circular cylinder with whirling limitation was performed using the boundary element method combined with the vortex method. The flow feature of vortex shedding and the characteristics of vibration due to the fluid force were simulated about various initial setting position of circular cylinder at the Reynolds number Re=1×105, the mass ratio M=5.15, the damping factor C=0.0 and the reduced velocities Vr=1.8 and Vr=2.4. As a result of calculation, in the case of coaxial setting, the flow feature and the characteristics of cylinder vibration due to the fluid force were as same as a result of self-oscillating case, however, in the case of not coaxial setting, the frequency of cylinder's motion was changed and the flow features were changed from the twin type vortex shedding pattern to the Karman type vortex shedding pattern. It was shown that the characteristic of cylinder vibration frequency depended on both of the distance and the direction between the circular cylinder and the wall of pit.