Session Cd - Interfacial & Thin-Film Instabilities.
ORAL session, Sunday, November 23
304, Moscone Center
The stability of a liquid layer under strong blowing and subject to large shear forces is investigated. This case is of practical importance for applications such as the regression rate estimation of cryogenic hybrid rockets. An Orr-Sommerfeld equation for the linear stability of the liquid gas interface is derived and an exact solution is found for a linear base velocity profile. The exact solution for the liquid phase is coupled to the linearized gas phase response with appropriate boundary conditions at the interface to give an eigenvalue problem for the linear stability of the layer. The results for liquid layer Reynolds numbers of practical interest (50-300) show the existance of a range of unstable wave numbers. It is observed that both the most amplified wave number and the maximum amplification increases with the Reynolds number. At these moderately high Reynolds numbers the effect of gravity is small.