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Unformatted text preview: eparate, or stall, if its half-angle is greater than
Between lines aa and bb is a transitory stall pattern with strongly unsteady flow.
Best performance, i.e., highest Cp, occurs in this region. The third pattern, between bb
and cc, is steady bistable stall from one wall only. The stall pattern may flip-flop from
one wall to the other, and performance is poor. | e-Text Main Menu | Textbook Table of Contents | Study Guide 384 Chapter 6 Viscous Flow in Ducts The fourth pattern, above line cc, is jet flow, where the wall separation is so gross
and pervasive that the mainstream ignores the walls and simply passes on through at
nearly constant area. Performance is extremely poor in this region.
Dimensional analysis of a flat-walled or conical diffuser shows that Cp should depend upon the following parameters:
1. Any two of the following geometric parameters:
a. Area ratio AR A2/A1 or (De /D)2
b. Divergence angle 2
c. Slenderness L/W1 or L/D
2. Inlet Reynolds number Ret V1W1/ or Ret V1D/
3. Inlet Mach number Mat V1/a1
4. Inlet boundary-layer blockage factor Bt ABL/A1,...
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This note was uploaded on 10/27/2009 for the course MAE 101a taught by Professor Sakar during the Spring '08 term at UCSD.
- Spring '08