Theoretical problem：entropy & pressure

Sun Yachuan · July 19, 2015, 12:38

I'm learning this book<Computational Fluid Dynamics The Basics with Applications>John D.Anderson,JR

I have some questions in section7.6.1
1.wath's the relationship between entropy & pressure?(why pressure is constant while entropy is constant? Why p02<p01 while s2>s1?)
2.Why A1*=At,obviously,they are not equal in FIG 7.22 ?

[IMG]https://drive.google.com/file/d/0B5r9Dn4RejRLTHZOakhReUdCZmM/view?usp=sharing
https://drive.google.com/file/d/0B5r9Dn4RejRLRE9CNUJwYmFKRVU/view?usp=sharing[/IMG]

beer · July 27, 2015, 14:38

Hi

you're in the wrong forum. Anyway:

1. It says the total pressure is constant. The pressure does change indead.
2. A* is the sonic throat, which is At berfore the shock. A* is just the area at which you reach Ma=1 for the first time.

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July 27, 2015, 14:38		#2
beer Member Join Date: Dec 2012 Posts: 92 Rep Power: 12	Hi you're in the wrong forum. Anyway: 1. It says the total pressure is constant. The pressure does change indead. 2. A* is the sonic throat, which is At berfore the shock. A* is just the area at which you reach Ma=1 for the first time.