SECONDARY INSTABILITY IN THE WAKE OF A CIRCULAR-CYLINDER

Secondary instability of flow past a circular cylinder is examined usi ng highly accurate numerical methods. The critical Reynolds number for this instability is found to be Re-c = 188.5. The secondary instabili ty leads to three-dimensionality with a spanwise wavelength at onset o f 4 cylinder diameters. Three-dimensional simulations show that this b ifurcation is weakly subcritical. (C) 1996 American Institute of Physi cs.