MHD Flow due to the Nonlinear Stretching of a Porous Sheet

الملخص EN

The MHD flow due to the nonlinear stretching of a porous sheet is investigated.

A closed form solution is obtained when the stretching rate is inversely proportional to the distance from the origin.

Otherwise a uniformly valid asymptotic expansion, for large magnetic interaction number β ~ ∞ , is developed.

It coincides with a homotopy perturbation expansion for the problem.

The asymptotic/homotopy perturbation expansion gives results in excellent agreement with accurate numerical results, for large as well as small values of β .

For large β , the expansion, being asymptotic, needs a small number of terms, regardless of the mass transfer rate or the degree of nonlinearity.

For small β , the expansion is a homotopy perturbation one.

It needs considerably increasing number of terms with higher injection rates and/or with stretching rates approaching the inverse proportionality.

It may even fail.