Dynamics of a bifurcating flow within an open heated cavity

A numerical study of a 2D jet, confined in a heated or nonheated "horse shoe" cavity containing a blu body is presented. Over critical conditions, this 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 for both streamwise and spanwise renormalized amplitudes emphasizes this global behavior. The stabilizing eect of the heated wall boundaries is shown. As an example, a delay of 6% for1TD 10 K, the temperature dierence between the walls and the working fluid, raises the onset of the self-sustained mechanism. The global mode conservation with heating boundaries proves that the confined jet is insensitive to external perturbation such as heating. © 2001 Editions scientifiques et medicales Elsevier SAS instability / Hopf bifurcation / oscillation frequency / thermal stabilization / global mode