Foa 



Fig. 5 - Radial-flow crypto- 

 steady pressure exchanger 



^--^-^^-U^UZZZZZ2^ 



Fig. 6 - Axial-flow cryptosteady 

 pressure exchanger 



is somewhat similar to that of fan or propeller blades. Similarly, the effect of 

 the interface pressure forces on the primary flow is essentially the same as the 

 energy -extracting action of a turbine. Figure 7 is a flash photograph of these 

 pseudoblades. Here water was used as the primary fluid, for the purpose of 

 visualization. The flow of water is parallel to the interfaces in f but not in f , 

 as shown by the streaks, which are particle path lines in f . 



THE BLADELESS PROPELLER -AVAILABLE THEORIES 



Figure 8, which is taken from Ref. 5, shows a schematic section view of a 

 typical thrust augmenter utilizing this mode of energy exchange — a "bladeless 

 propeller" — and identifies the angles that, following Hohenemser's terminology, 

 will hereafter be referred to as the "spin angle" and the "coning angle." 



The first analysis of the operation of this device (Ref. 6) dealt numerically 

 with a variety of specific cases, involving plane interactions between compres- 

 sible or incompressible flows, with or without separation of the two flows after 



1358 



