On the interaction of wall jets and fountain formation

An analysis of the fountain formation produced by the vertical impingement of two jets on a flat-ground surface is presented. A method has been developed for the determination of the upwash angle of the fountain in the plans of symmetry and the ground stagnation line. Comparison of the calculated results from the present analysis with tests data obtained by the Grumman Aerospace Corporation shows generally good agreement. The different methods of approach and results in some recent works regarding the upwash angle are discussed, and it is shown that the fountain should leave the ground surface in direction perpendicular to it, and approach the upwash angle asymptotically.