Interfacial instability and mixing in stratified flows

Abstract

When a liquid flow s over a body of heavier liquid, \yith which it is mi scible, an int erface may be formed at which there is a sharp di sco ntinuity of de nsities but not necessaril y of velocities. As the r ela t ive ve locity is increased, waves are form ed a t the interface, and a( a critical velocity, mixing beg ins by the formation of edd ies peri od icall.v ejected f rom the cr ests of the waves. The nume ri cal valu es of a: cri terion for mixing, whose form was derived from theo retical cons id eratio ll s, were de te rmi ned experim e ntall y. Expe rim ental data were also obtained on t he re lation of the amount of mixing to the relative velocit~1 of t he liqllid ~ at vc loc iLies high er Lhan Lhe critical.