COMPUTATIONAL STUDY OF FLOW PAST A CYLINDER WITH COMBINED IN-LINE ANDTRANSVERSE OSCILLATION

A computational study of the two dimensional flow past an oscillating cylinder is carried out using vorticity and stream function as the dep endent variables. With the use of a log-polar coordinate transformatio n, the nondimensional vorticity transport equations in a non-inertial frame attached to the cylinder are solved using the ADI and SLOR finit e difference schemes. The effects of combined in-line and transverse o scillation of the cylinder in the ''lock-in'' range of frequency on th e time history of the drag and lift are investigated at a Reynolds num ber of 100. In addition, the influence of position amplitude of the cy linder's transverse oscillation on the lock-in range of frequency, mea n drag, amplitude of drag and maximum lift is studied. The time histor ies of drag and lift forces in the case of combined oscillation are co mpared with the cases of the cylinder oscillating in the in-line and t ransverse directions separately. The dominant frequency components in the drag and the lift variations are determined using a Fourier freque ncy analysis.