Role of the Interface in the Stability of Stratified Flow down an Inclined Plane

Abstract

For the case in which the density of the upper layer is somewhat less than that of the lower layer, a second mode essentially associated with the interface is found to govern the stability of the flow. However, when the upper density becomes much smaller, the free surface mode and the second mode compete for governing the stability. A clarification of the mechanism involved is given. The Reynolds stress transfer of energy at the interface is estimated and is found to be insignificant for long waves.