Dynamic analysis on fluid-structure interaction of an elastically mounted square cylinder at low Reynolds numbers

Fluid-structure interaction of an elastically mounted rigid square cylinder of low non-dimensional mass immersed in fluid flow is investigated numerically in the Reynolds numbers range of 60≤Re≤250. The square cylinder is allowed to freely vibrate only in the transverse direction perpendicular to the incoming flow. The two-dimensional incompressible Reynolds-averaged Navier-Stokes equations are solved by the finite volume method for the fluid flow. The equation of motion is solved for the vibration of the square cylinder. The results show that abrupt both the frequency and amplitude ratios curves experience sudden change at Re=90 and 168, which marks the onset of the lock-in and galloping regime, respectively. Thus, four regimes can be divided in the present study and which are the initial regime, the lock-in regime, the lower branch and galloping regime. A local peak value is observed in the force coefficients curve and the maximum value is reached at Re=231. It is found that the peak oscillating amplitu...