how to use the parameter of LUSGS methold
I just compute a 3D incompressible unsteady fluid use the LUSGS methold. But it convergence is too slower. Can you tell me? how to use the parameter

Re: how to use the parameter of LUSGS methold
which parameter do you mean ? Referring to what paper ?
LUSGS based on Roe scheme with roe matrix approximated by its spectral radius or Block LUSGS wich exact jacobians for the main diagonal and exact flux differences for the offdiagonal terms ("exact" = flux difference with the flux function that is also used for the spatial operator) LUSGS as solver or as preconditioner for Krylov subspace method ? Frank 
Re: how to use the parameter of LUSGS methold
I just have read the
1: LowerUpper SymmetricGaussSeidel Method for then Euler and NavierStokes Equations author:Yoon S. and Jameson A. AIAA J. Vol 26 No.9 p10251026 2: ThreeDimensional Incompressible NavierStokes Solver Using LowerUpper SymmetricGaussSeidel Algorithm author:Yoon S. and Kwak D. AIAA J. Vol 29 p874875 they both used the parameters of pseudocompressiblility¡¡¦Â and¡¡¦Á¡¡and ¦Ê¡¡¡£ a).this is the use of the ¦Ê A¡À=1/2[A¡&Ñ(A)I] ¦Ñ(A)=¦Ê max[¦Ë(A)] b).the following is the using of the ¦Á the discreted Equations are [I+¦Á¦¤t(D¦ÎA+D¦ÇB+D¦ÆC)]¦ÄQ=¦¤tR c).¦Â multiple pseudotime derivative of pressure was andded to the continuity equation. how to use the a suit of the parameter? I think ¦Ê and ¦Â affected each other at least. Thank you for your help! ¡¡ 
Re: how to use the parameter of LUSGS methold
Check L. Dailey's recent (after 1996) paper. You may get some useful information.

Re: how to use the parameter of LUSGS methold
Thank you John. Can you give me more detail about it, so I can search for the paper.

Re: how to use the parameter of LUSGS methold
The LUSGS scheme of approximate spetral radius version can not directly compute unsteady flow due to lack of time accuracy. To be general, alfa=1, kappa=1, and beta=1 is a good baseline choice. Acceleartion may be obtained from combination of kappa and beta, but no general rules exist for different problems. Another approach os Preconditioning. To my knowlege, there are no strong recommendations using Preconditioning from the authors.

Re: how to use the parameter of LUSGS methold
Thank you,Versi. I will take a test of alfa=1, kappa=1, and beta=1. I have never compute this suit.
But can you tell me, there are other methold can accelerate the solution recently. 
Re: how to use the parameter of LUSGS methold
I don't have the exact reference title, but I guess you can send an email at pletcher@iastate.edu to ask about Dailey's papers and thesis. Dr. Pletcher was his Ph.D advisor. I've used those papers and thesis for my research and I got more than enough information about LUSGS scheme. Good luck.

Re: how to use the parameter of LUSGS methold
Thank you. I have sent a mail to him.
My purpose is to find a effective methold to accelerate the current methold we used and my classmate told me the LUSGS may be faster. I take a look at the process of this methold and find that it calculates less than ours. So I think it may be work. I aslo studied other papers and got a methold of ILU(0)+GMRES. I can't find the 3D ILU(0) formula. Referenced from: A Comparison of Impicit Schemes for the Icompressible NavierStokes Equations with Artificial Compressibility Stuart E. Rogers AIAA Paper 950567 What is your major? Can you help me about this? Thanks for you. 
All times are GMT 4. The time now is 09:47. 