# Free surface flow under gravity and surface tension due to an Applied Pressure Distribution II bond number less then one-third

preprint

posted on 22.07.2005, 09:53 by Montri Maleewong, Roger Grimshaw, Jack AsavanantWe consider steady free surface two-dimensional flow due to a localized applied
pressure distribution under the effects of both gravity and surface tension in water of
a constant depth, and in the presence of a uniform stream. The fluid is assumed to be
inviscid and incompressible, and the flow is irrotational. The behaviour of the forced
nonlinear waves is characterized by three parameters: the Froude number, F, the
Bond number, τ < 1/3, and the magnitude and sign of the pressure forcing term ǫ.
The fully nonlinear wave problem is solved numerically by using a boundary integral
method. For small amplitude waves and F < Fm < 1 where Fm is a certain critical
value where the phase and group velocities for linearized waves coincide, linear
theory gives a good prediction for the numerical solution of the nonlinear problem
in the case of a bifurcation from the uniform flow. As F approaches Fm, however,
some nonlinear terms need to be taken in the problem. In this case the forced
nonlinear Schr¨odinger equation is found to be an appropriate model to describe
bifurcations from an unforced envelope solitary wave. In general, it is found that
for given values of F < Fm and τ < 1/3, there exist both elevation and depression
waves.

## History

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- Science

## Department

- Mathematical Sciences