  Using extended Layzer's potential flow model, we investigate the effects of
surface tension on the growth of the bubble and spike in combined
Rayleigh-Taylor and Kelvin-Helmholtz instability. The nonlinear asymptotic
solutions are obtained analytically for the velocity and curvature of the
bubble and spike tip. We find that the surface tension decreases the velocity
but does not affect the curvature, provided surface tension is greater than a
critical value. For a certain condition, we observe that surface tension
stabilizes the motion. Any perturbation, whatever its magnitude, results stable
with nonlinear oscillations. The nonlinear oscillations depend on surface
tension and relative velocity shear of the two fluids.
