Ak. Dhar et Kp. Das, STABILITY ANALYSIS FROM 4TH-ORDER EVOLUTION EQUATION FOR SMALL BUT FINITE-AMPLITUDE INTERFACIAL WAVES IN THE PRESENCE OF A BASIC CURRENT SHEAR, Journal of the Australian Mathematical Society. Series B. Applied mathematics, 35, 1994, pp. 348-365
A fourth-order nonlinear evolution equation is derived for a wave prop
agating at the interface of two superposed fluids of infinite depths i
n the presence of a basic current shear. On the basis of this equation
a stability analysis is made for a uniform wave train. Discussions ar
e given for both an air-water interface and a Boussinesq approximation
. Significant deviations are noticed from the results obtained from th
e third-order evolution equation. which is the nonlinear Schrodinger e
quation. In the Boussinesq approximation, it has been possible to comp
are the present results with the exact numerical analysis of Pullin an
d Grimshaw [12], and they are found to agree rather favourably.