Cryptosteady modes of energy exchange

Cryptosteady modes of direct fluid-fluid energy exchange, as occurs in thrust augmenting ejectors and jet pumps, make use of the fact that a flow which is not uniform throughout can be steady in no more than one frame of reference. They thereby transform a steady flow interaction into a nonsteady one by the simple artifice of using it in a frame of reference other than the unique one in which it is steady. The reference frame is then given the benefit of pressure exchange, while retaining the control advantages of steady flow in the other one. Attention is given to rotary jet devices based on cryptosteady effects, as well as thrust augmentors based on the rotary jet.