Van der Hegge Zijnen

The facdor K would be 1 in the case of full momentum recoveiy, or 0.5 in the case of negligible viscous losses in the portion of flow which remains in the pipe after the flow divides at a takeoff point (Denn, pp. 126-127). Experimental data (Van der Hegge Zijnen, Appl. Set. Re.s., A3,144-162 [1951-1953] and Bailey, ]. Mech. Eng. ScL, 17, 338-347 [1975]), while scattered, show that K is probably close to 0.5 for discharge manifolds. For inertiaUy dominated flows, Ap will be negative. For return manifolds the recovery factor K is close to 1.0, and the pressure drop between the first hole and the exit is given by... 

Similar to the case with compact air jet supply, theoretical values of characteristic depend upon the type of velocity profile equation and supply conditions. According to Shepelev, = 2.62. The Gortler profile results in Kj = 2.43 and the Tollmein profile in iCj = 2.51. Becher " reported the A, characteristic for a linear jet to be equal to 2.55. Experimental results by Heskestad, Miller and Comings,van der Hegge Zijnen, 238 Gutmark and Wygnanski, and Kotsovinos and List appear to satisfy A, = 2.43,... 

This idea was first used by Van der Hegge Zijnen (VI) and Douglas and Churchill (D4) in developing correlations for cylinders in crossflow. 

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