Application of Padé approximants to the study of plane jets

In the present paper, the Padé approximants technique is applied to the study of plane jets. In order to verify the applicability of this technique in jet flows, two problems having different flow field characteristics have been chosen as test cases. In the first case, the fluid-dynamic field of a jet emerging in a medium in motion at constant velocity is analysed; in the second case, the external medium is at rest, but together with the jet, is subjected to the external force of a transverse magnetic field. In both cases, the jet issues in a medium having its same properties. The laminar boundary layer equations have been solved by first expanding the stream function in a Taylor series in terms of a suitable power of the abscissa, and then by analytically continuing the series by means of the Padé approximants. The accuracy of the results has been tested by the comparison of the velocity distributions obtained by Padé approximants with those calculated by an asymptotic solution holding for large values of the abscissa in the first case, and with the analytical solution in the second case.