Compressible Flows Obtainable From Two-Dimensional Flows Through the Addition of a Constant Normal Velocity

1946 ◽  
Vol 13 (1) ◽  
pp. A61-A65
Author(s):  
H. Poritsky

Abstract This paper demonstrates that exact solutions of the flow of compressible fluids can be obtained by starting with two-dimensional steady-state flows and superposing upon them a velocity of constant magnitude and direction at right angles to the planes of the two-dimensional flows, while at the same time, the pressure, density, and temperature of the fluid at each point are unchanged. The procedure is demonstrated by several examples, one of which is of interest in connection with the discharge of exhaust gases from a gas engine through the tail cone and tail pipe in cases where the circulation has not been completely removed from the flow. Another example is the flow around a “sweepback” or “arrow” wing. This example is illustrated for supersonic flows on plane oblique shocks and on the Meyer-Prandtl expansion around an edge.

1960 ◽  
Vol 9 (2) ◽  
pp. 161-174 ◽  
Author(s):  
Chia-Shun Yih

Three classes of exact solutions for steady two-dimensional flows of a stratified fluid are found. The flows which correspond to these solutions have arbitrary amplitude (however defined). Two of the three classes of solutions have close bearings on the lee-wave problem in meteorology. It is also shown that the amplitudes of the lee-wave components (if there is more than one component) depend not on the details of the shape of the barrier, but only on certain simple integral properties of the function for the singularity distribution generating the barrier.


The ‘profile’ methods of boundary-layer theory are adapted to predict the behaviour of the transient flames resulting from contact of semi-infinite burnt and unburnt gas masses, contact of unburnt gas with an adiabatic catalyst, immersion of a finite slab of unburnt gas in a large mass of hot gas, and immersion of a finite slab of burnt gas in a large mass of unburnt. Comparison with some exact solutions suggests that the accuracy is normally better than 20%. The method is simple to use. The results are also relevant to two-dimensional steady-state flames.


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