STABILITY OF DENSITY STRATIFIED FLOW IN THE BOUNDARY LAYER

1. INTRODUCTION The influence of vertical density variations o the stability of flow past a flat horizontal wall, is in sense related to the case of centrifugal forces actin on a homogeneous fluid flowing along a curved wal When the arrangement is stable, the densit decreases upward, , whereas it becomes unstabl when the variation in density is reversed. In the cas of flow with stable density stratification, turbulen mixing in the vertical direction is impeded becaus heavier particles must…

Stability of density stratified flow in the boundary layer

The stability of the laminar flat plate boundary layer is investigated numerically by solving the linear Orr–Sommerfeld equations for the disturbulence amplitude function. These equations include the terms of viscosity, density stratification, and diffusion. Neutral stability curve and the critical Re numbers are computed for various Richardson (Ri) numbers and Schmidt (Sc) numbers. The results show that the larger the Ri, the larger the critical Re for Sc<10. The flow is stable for Ri<0, when Sc is very small or the mass diffusion coefficient is very large. But for Ri>0, the effects of diffusion are reversed for Sc<10. ForSc>10, the critical Re rapidly decreases to zero as the Sc increases for a given Ri number. The critical Re rapidly decreases as the Ri increases.