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January 8, 2013, 05:24 |
which boundary condition is true?
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#1 |
Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 26 |
hi.
I have used 3 types of boundary conditions with three different results! The patch i assigned BC on is outflow.these scenarios are examined: ____________________ 1)firstly pressure is specified through p0 as isentropic formul: p=p0*(1+(gama-1)/2*U^2/(gama*R*T))^(-gama/(gama-1)) U and T are zero gradient.at this pressures are obtained less than expected. ----------------- 2)at second i set T=T0-(gama-1)/(2*gama*R)*U^2 And U and p are assumed zero gradient. This approach results in more higher pressures. --------------------- 3)both p and T are specified: p=p0*(1-(gama-1)/(2*gama*R*T0)*U^2)^(gama/(gama-1)) And T=T0-(gama-1)/(2*gama*R)*U^2 (as second case) This approach leads to diverge after 200 iterations. So as it tooks one month so far and remaind a little time for me why these conditions result so differently?whats the cause or the causes? Any knowledge,advice and idea is much appreciated. Thanks for attention. |
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