[petsc-users] Modify RHS values at each iteration

[Åsmund Ervik]

Hi Tay,

I've just been working on ways to get more accurate pressure from the
Poisson equation. I can highly recommend this article by Guermond and
coworkers:

http://dx.doi.org/10.1016/j.cma.2005.10.010

It's so long that it may be scary, but just reading 3.1 and 3.2 gives
quite a bit of information already. The article sums up the literature
quite nicely.

Regards,
Åsmund Ervik


> Date: Thu, 21 Nov 2013 18:06:11 +0800
> From: TAY wee-beng <zonexo at gmail.com>
> To: Jed Brown <jedbrown at mcs.anl.gov>,  PETSc list
> 	<petsc-users at mcs.anl.gov>
> Subject: Re: [petsc-users] Modify RHS values at each iteration
> Message-ID: <528DDB13.7080208 at gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> Hi Jed,
> 
> I need a solve a Poisson equation, which is part of my finite volume CFD 
> code.
> 
> The RHS terms are calculated from the velocity.
> 
> In the standard mtd, the RHS terms are calculated from the velocity, 
> which then solves the Poisson eqn to get the pressure.
> 
> Now, to improve the accuracy of the pressure obtained, a paper suggested 
> obtaining the pressure  from the velocity in 1 iteration. Then use the 
> new pressure for the momentum eqn to get a more accurate intermediate 
> velocity. The RHS terms are recomputed again using the new velocity, 
> which is then used to calculate the new pressure. This cycle goes on 
> until the pressure converges to a certain value.
> 
> Hence, I wonder what is the best way to do it.
> 
> Thanks!
> 
> Yours sincerely,
> 
> TAY wee-beng
> 
> On 21/11/2013 3:44 PM, Jed Brown wrote:
>> TAY wee-beng <zonexo at gmail.com> writes:
>>> Hi, in that case, do you want any suggestion? Is it possible to apply
>>> the preconditioner only once at the start, and not at every intermediate
>>> step?
>> You'll have to explain what you are trying to do.
>