NUMERICAL SIMULATION OF FLOW PAST A CIRCULAR CYLINDER IN ELLIPTIC ORBIT AT LOW REYNOLDS NUMBER

Two-dimensional fluid flow around an oscillating circular cylinder in elliptic motion at Reynolds number 300 is investigated numerically for different oscillation frequency and orbit ellipticity. An original fully coupled numerical method is used for simulating the non-stationary flow. Occurrence of lock-in, characterized by a large jump of fundamental quantity values, is observed and lock-in regions are determined. Under lock-in conditions, mean lift coefficient pre-sents negative and positive values. The variations of fluctuating lift and mean drag coefficients show different behavior and slope of curves change with ellipticity. Curve of fluctuating drag coefficient widely changes and maximum value is not reach for the highest lock-in frequency, like the other fundamental quantities, but for a frequency all the more small since the ellipticity is large.