Experiments on Starting Homogeneous Jets

Abstract

A qualitative description of the axial motion of the starting homogeneous round water jet is presented by dividing the jet trajectory in three regions. The jet front accelerates after the exit and reaches a maximum axial velocity at the distance of nine diameters. Beyond an axial distance of twenty diameters the starting jet motion has a constant deccelerating character and an axial velocity constantly less than the steady jet velocity. In the intermediate region the motion has a transitional behavior. The starting homogeneous jet geometry is similar to the starting plume geometry.