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发表于 2014-2-25 08:26:31
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原帖由 flowinflow 于 2014-2-24 17:06 发表
Could you please go a bit into details? What you said is too general
to be useful.
The problem is you cannot start Newton iteration UNLESS the solution
is near the stationary point, but you woul ...
1. Could you tell me what is the enssitial of implicit scheme of the steady case ?
2. About the "Start-Up problem", there are too many contributions,such as Hong luo's, Zhijian Wang's and so on, you can find. You are may be a undergraduate student. What I do and can only do is giving you some directions. You need to research them yourself.
3. About the robustness of the code, there are still a lot of things to be done in CFD. Most of the time, high accuracy and high robustness is conflict. We need struck a medium.
4. The success to achieve the Newton iteration and quadratic convergence depends on the good initial state and good preconditioner. For the good initial state, it is the "Start-Up problem". About the scond factor, you can
choose LUSGS,Multigrid and so on as the preconditioner.
"I think what most (if not all) people do is trial and error." I partially agree. Different case, different relaxation parameters. But the technique we adopt has theoretical background and also the trial should not be entirely groundless.
[ 本帖最后由 lwd1981 于 2014-2-25 03:03 编辑 ] |
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