Dynamics of a bifurcating flow within an open heated cavity

A numerical study of a 2D jet, confined in a heated or nonheated "horse sho e" cavity containing a bluff body is presented. Over critical conditions, t his system exhibits self-sustained oscillations with well defined saturated 'amplitude and frequencies. Through the oscillating velocity amplitudes and the phenomenon frequencies, we defined a global mode. A universal curve fo r both streamwise and spanwise renormalized amplitudes emphasizes this glob al behavior. The stabilizing effect of the heated wall boundaries is shown. As an example, a delay of 6 % for DeltaT = 10 K, the temperature differenc e between the walls and the working fluid, raises the onset of the self-sus tained mechanism. The global mode conservation with heating boundaries prov es that the confined jet is insensitive to external perturbation such as he ating. (C) 2001 Editions scientifiques et medicales Elsevier SAS.