
[Sponsors] 
September 11, 2015, 03:14 
Acoustic Perturbation Equations (APE)

#1 
New Member
Sergej
Join Date: Aug 2015
Location: Cologne, Germany
Posts: 10
Rep Power: 7 
Hello everybody,
i am new at OpenFoam, but i read much theory of it and now I would like to implement the Acoustic Perturbation Equations (APE) in OpenFoam. I think it would not be very easy, so i hope that maybe somebody here have made experience with it. Here is the relevante paper link: http://www.sciencedirect.com/science...21999103001682 If you are a student, then it is mybe for free, if you log in with VPN of your university. So if i get some experience with it i will share it here. 

February 24, 2016, 14:50 

#2 
Senior Member
Hasan K.J.
Join Date: Dec 2011
Location: Bristol, United Kingdom
Posts: 200
Rep Power: 11 
Dear Tonky,
By any chance did you have any luck in implementing APE in OpenFOAM. Regards, Hasan K.J
__________________
"Real knowledge is to know the extent of one's ignorance."  Confucius 

September 27, 2016, 10:20 

#3 
New Member
Sergej
Join Date: Aug 2015
Location: Cologne, Germany
Posts: 10
Rep Power: 7 
Hello Hasan,
after some practice with OF, I have started to work further on the implementation of APE2 theory. But now I am facing some problems, which I am now trying to solve, also with the help of cfdonline.com. I noticed that the equations of "APE2" are similar to the equations of Seo and Moon in "Linearized Perturbed Compressible Equations": http://www.cfdonline.com/Wiki/Hydro...stic_splitting But my problem is now that i implemented the following three equations (see attached files) and I am solving them on the explicit way (diagonal solver) and the values of rho' and u' are increasing during the simulation without a limit. Now I am trying to implement them on the implicit way. Is this possible and if yes, how? Hasan, did you have some experience with APE? 

September 30, 2016, 05:44 
how to solve coupled equations?

#4 
New Member
Sergej
Join Date: Aug 2015
Location: Cologne, Germany
Posts: 10
Rep Power: 7 
Hello Foamers,
I have read many posts here in cfdonline, but could not solve my problems with the iterations with the number of zero. I implemented the three equations in the following form: Code:
solve(fvm::ddt(rhoS)+ rhoS * (fvc::div(averageU)) ==  rho * (fvc::div(Ua)) ); Code:
solve(fvm::ddt(Ua)+ fvc::grad(averageU & Ua) ==  fvc::grad(pa)); Code:
solve(rho*fvm::ddt(pa) c0*c0*fvc::ddt(rhoS) ==  rho*fvc::ddt(pS)); 

January 21, 2018, 22:20 
Dear Tonky, Have you solved your problems?

#5  
New Member
Join Date: Jan 2018
Posts: 7
Rep Power: 4 
I'm getting in trouble with APE in OpenFOAM too...Thanks!
Quote:


Tags 
acoustic, aeroacoustics, implementation, open foam, perturbation equations 
Thread Tools  Search this Thread 
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Guide: Writing Equations in LaTeX on the CFD Online Forums  pete  Site Help, Feedback & Discussions  28  February 17, 2020 08:43 
how to solver perturbation equations of navier stokes equations ?  mechy  OpenFOAM Programming & Development  1  June 8, 2014 17:04 
modelling Differential equations in a udf  RikardMNorén  Fluent UDF and Scheme Programming  2  October 1, 2013 03:36 
CFD governing equations  m.gos  Main CFD Forum  0  April 30, 2011 14:21 
exact solution of acoustic equations  pran  Main CFD Forum  0  February 14, 2002 02:46 