SPATIAL INSTABILITY OF PLANAR CHANNEL FLOW WITH FLUID INJECTION THROUGH POROUS WALLS

The present paper deals with the stability properties of a planar chan nel flow driven by air injection through porous walls. Experimental in vestigations have been carried out in the so-called VECLA facility and a theoretical linear stability analysis has been performed. The nonpa rallel effects are studied by using three different stability approach es. They appear to be very significant for this particular flow. This study provides indeed an interesting example of an instability mechani sm strongly related to the vertical component (usually negligible) of the mean Row. The obtained results finally agree very well with the me asurements with respect to the amplified frequency range and to the st reamwise amplification of the instability waves. (C) 1998 American Ins titute of Physics.