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Temperature calculation from sensible internal energy |
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April 12, 2019, 06:42 |
Temperature calculation from sensible internal energy
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#1 |
New Member
Matteo
Join Date: Jan 2019
Posts: 4
Rep Power: 7 |
Hi guys. I'm writing a code using the NACA0012 airfoil tutorial for rhoSimpleFoam compressible solver as a guide.
Actually I'm not able to figure out how the temperature is calculated. I mean, If I'm right everything should be done inside the hePsiThermo.C and thermoI.H files where thermo.correct() and calculate() functions are defined. Temperature calculation is coded this way: Code:
Test = Tnew; Tnew = (this->*limit) (Test - ((this->*F)(p, Test) - f)/(this->*dFdT)(p, Test)); Inside the thermophysicalProperties these are the selected parameters: Code:
thermoType { type hePsiThermo; mixture pureMixture; transport const; thermo hConst; equationOfState perfectGas; specie specie; energy sensibleInternalEnergy; } Code:
template<class Thermo, template<class> class Type> inline Foam::scalar Foam::species::thermo<Thermo, Type>::Es(const scalar p, const scalar T) const { return this->Hs(p, T) - p/this->rho(p, T); } Code:
template<class Thermo, template<class> class Type> inline Foam::scalar Foam::species::thermo<Thermo, Type>::es(const scalar p, const scalar T) const { return this->Es(p, T)*this->W(); } Does anyone of you know what it stands for and why it should be there? I cannot understand exactly which is the whole functional I have to use inside the Newton iterations. Thanks a lot to anyone who can help me. |
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April 12, 2019, 15:48 |
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#2 |
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April 15, 2019, 10:44 |
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#3 |
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Matteo
Join Date: Jan 2019
Posts: 4
Rep Power: 7 |
Thank you for the answer. Unfortunately I've already seen that post and there are two points making it unuseful to me:
1 in that case enthalpy is considered instead of sensible internal energy; 2 the Newton method part is not explained, they just say a Newton method is applied and nothing more. Is there anybody having an answer to my doubats? |
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April 15, 2019, 15:11 |
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#4 |
Senior Member
Join Date: Aug 2015
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The code for the newton method is provided, so I don't see the problem. Or a quick google search for the newton method will provide answers. Following the nice explanation in the link provided, we can find equivalent functions to back out temperature from internal energy -- it actually uses the same newton method, just with different inputs :
Code:
template<class Thermo, template<class> class Type> inline Foam::scalar Foam::species::thermo<Thermo, Type>::TEs ( const scalar es, const scalar p, const scalar T0 ) const { return T ( es, p, T0, &thermo<Thermo, Type>::Es, &thermo<Thermo, Type>::Cv, &thermo<Thermo, Type>::limit ); } Caelan |
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April 16, 2019, 04:46 |
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#5 |
New Member
Matteo
Join Date: Jan 2019
Posts: 4
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Probably I did not exlain well what I'm looking for. I've already written what you posted in the last reply in the first part of my thread. I know what a Newton method is, I know I have to put F=Es and f=es. The point is that I cannot understand the physical meaning of es or, if you prefer, which is the physical functional I have to put equal zero for the Newton method: x1 = x0 - G(x0)/G'(x0). What is G(x) in my case?
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April 16, 2019, 10:37 |
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#6 | |
Senior Member
Yan Zhang
Join Date: May 2014
Posts: 120
Rep Power: 12 |
Quote:
Code:
T_new = T_old - [ Hs(p_old,T_old) - hs_fromTransportEqn]/ Cp(p_old,T_old)
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