Jet Width and Volume Rate of Flow

The fluid velocity attains its maximum on the flow axis and decreases according to the law f/max X l/,(3n). Thus, the smaller n, the more rapid the velocity decreases. 

We define the 1%-width S(X) of the jet as twice the distance from the jet axis to a point with coordinate y° at which the longitudinal velocity differs from its limit value by 1%  

It follows from (6.8.13) that for n the jet is convex outward, for n = the jet boundaries are rectilinear, and for n the jet boundaries are diverging parabolas with a cuspidal singular point on the flow axis. 

Now we calculate the volume rate of flow per unit length of the opening as follows  

For j n 2, we must substitute F( oo) from (6.8.12) into (6.8.14). Obviously, the rate of flow increases with the distance from the opening, since the jet entrains the stagnant fluid on its sides. The rate of flow also increases with increasing momentum. As the index n decreases from 1 to the rate of flow grows 

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