STUDY OF A JET INCIDENT ON A POROUS WALL IN A GRAVITY-FIELD

The problem of an inviscid jet impacting on a porous wall in a gravity field is considered. By transforming this into a minimum problem, exi stence and uniqueness results are proved. Properties of the flow regio n, of the stream function, and of the free boundary are established. T he monotonicity of the stream function with respect to the given veloc ities is also obtained. The mathematical results established allow one to obtain and to compare the numerical approximations of the stream f unction and of the free boundary for the flows, with and without gravi ty, by using a finite-element method.