Weak nonlinear effects on interfacial wave formation

Abstract

The authors have performed an inviscid stability analysis of two-layer flow with tanh stream velocity distribution, considering perturbations of second order. Results of the analysis show good agreement with measurements of the phase relationship between concentrated vortices directly above and below the interface which were due to shear instability, and interfacial waves. Also, these analytical results lend increased credence to the growth mechanisms for Keulegan waves and Cycloidal waves over linear theory as mathematical models.