EXPERIMENTAL-OBSERVATIONS AND MARGINAL STABILITY CALCULATIONS FOR COUNTERFLOWING STREAMS WITH SWIRL

In this paper reports are given on laser-Doppler velocimeter measureme nts on counterflowing water streams with swirl. The experiments lend q ualitative support to,previous theory and computations [Goddard, Didwa nia, and Wu, J. Fluid Mech. 251, 149 (1993)] of the effects of swirl a nd confinement on the hydrodynamic stability of this flow in the high- Re regime. In the present paper a linear stability analysis and comput ations of the marginal stability curve for self-similar, radially unco nfined flows are also given. This and the above-cited work serve to de fine the practical operating limits on an associated flow device for g enerating a uniformly accessible interface of mass or heat transfer be tween counterflowing fluid streams.