Hi Ed,

Sorry for the delayed response. Could you try removing EVAR="u v T p x y" from the forcing function only for T, for instance.

       <E VAR="u" VALUE="Gr*T" EVARS="u v T p" />
            <E VAR="v" VALUE="0" EVARS="u v T p" />
            <E VAR="T" VALUE="(1e10)*exp(-((x+0.25)^2+y^2)/(0.05^2))"/> 

The reason is because whenever EVAR (equation variables) is explicitly labelled, the forcing function look up the equation variables (u v T p) for the forcing values but not the space/time variables (x y t). 

Hope this helps!

Cheers,
Chi Hin


From: nektar-users-bounces@imperial.ac.uk <nektar-users-bounces@imperial.ac.uk> on behalf of Edward Threlfall <ejthrelfall@gmail.com>
Sent: 18 January 2023 16:35
To: nektar-users <nektar-users@imperial.ac.uk>
Subject: [Nektar-users] Help with spatially-varying sourcing function.
 

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Dear community,

I've set up a convection problem in the incompressible Navier-Stokes solver.

I have an equation for the time-evolution of the temperature to which I would like to add a right-hand-side describing sources of local heating.

Can I do this in Nektar++?  I have tried implementing it via the bodyforce, however this seems to apply a spatially-uniform source and I want something like the Gaussian profile below.

I am trying:

        <FUNCTION NAME="BodyForce">
            <E VAR="u" VALUE="Gr*T" EVARS="u v T p" />
            <E VAR="v" VALUE="0" EVARS="u v T p" />
            <E VAR="T" VALUE="(1e10)*exp(-((x+0.25)^2+y^2)/(0.05^2))" EVARS="u v T p x y" /> 
        </FUNCTION>

then 

    <FORCING>
        <FORCE TYPE="Body">
            <BODYFORCE> BodyForce </BODYFORCE>
        </FORCE>
    </FORCING>


Can anyone help, please?

Thanks!

Ed.