LAMINAR JETS WITH PARABOLIC VELOCITY DISTRIBUTION AT EXIT.

Jets issuing from a tube with parabolic velocity distribution at exit have been studied theoretically. The calculated results have been compared with experimental measurements. The momentum equation and the continuity equation with boundary layer approximation for the laminar flow have been solved by finite difference method. The jet is found to be laminar near the exit and it becomes turbulent after some axial distance which depends upon the exit Reynolds number. The laminar length reduces if the Reynolds number increases. The velocity profile in the laminar portion of the jet is not found to be of similar character. The momentum thickness in the laminar jet is linear with axial distance and it increases dramatically at some axial distance which indicates transition to turbulence. The calculated results are in satisfactory agreement with experimental results.