[Nek5000-users] Add a forcing term on scalar equation

[nek5000-users at lists.mcs.anl.gov]

Paul,

Numerically the momentum equation has an explicit forcing term.
Only that, it is based on the T at the same time. However, I would like to first solve the equation for the scalar.

In other words, I want to first solve the equation for T, use it to calculate f(T) and afterward solve the momentum equation ( u_t=NS + f(T) ). So How I can do that!?


Iman 





________________________________________
From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
Sent: Friday, January 20, 2012 2:25 PM
To: nek5000-users at lists.mcs.anl.gov
Subject: Re: [Nek5000-users] Add a forcing term on scalar equation

Iman,

These can be coupled explicitly, but not implicitly.   Usually, however,
this is sufficent.  Equation are of the form:

    u_t = NS +  f(u,T)

    T_t = energy eq. + q(u,T)

f & q explicit.   The code will take care of the bookkeeping.

Paul


On Fri, 20 Jan 2012, nek5000-users at lists.mcs.anl.gov wrote:

> Thanks.
> So I just used the "USERQ" to implement the forcing term to scalar filed explicitly.
>
> In the next step, I want to coupled the scalar field to Navier-Stokes equation using a forcing term.
> In this case, the forcing term is a function of scalar field and I would like to implement it implicitly.
> As far as I know, if I used USERF, the scheme is explicit. So how can I add a forcing term to N-S equation implicitly!?
>
> Iman
>
>
>
> ________________________________________
> From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
> Sent: Thursday, January 19, 2012 4:20 PM
> To: nek5000-users at lists.mcs.anl.gov
> Subject: Re: [Nek5000-users] Add a forcing term on scalar equation
>
> It's actually evaluated explicitly, so you shold be ok.
>
> Paul
>
>
> On Thu, 19 Jan 2012, nek5000-users at lists.mcs.anl.gov wrote:
>
>> Hi
>>
>> I would like to add a forcing term to the scalar equation.
>> According to the Nekton manual, Chapter 5, the forcing term is treated implicitly and the convective term is integrated using the third order Adam_Bashforth scheme (AB3).
>> For my case, the forcing term is a nonlinear function of the scalar field, so I cannot use the implicit scheme and I should lump it with the AB3.
>> Therefore, could you please guide me and indicate where in the code I can find the implementation of AB3 for the convective term of passive scalar?
>>
>> Cheers
>> Iman
>>
>>
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