[Nektar-users] how to use HOBC?

[Sherwin, Spencer J]

Hi Kurt,

The forcing is applied to the momentum equation rather then the velocity component. It is added as an explicit term which means it will appear in the Neumann pressure boundary conditions, the pressure Poisson solve forcing and  in the Helmholtz solve for consistency.

Cheers,
Spencer.


On 19 Mar 2018, at 18:32, Kurt Sansom <kayarre at gmail.com<mailto:kayarre at gmail.com>> wrote:

if the forcing is applied in the velocity component what does that mean in terms of how the solver works?
 does that mean that the forcing term is only applied in solving the Helmholtz  part or  is it applied in both the pressure poisson and
the Helmoholtz solve?

Regards,
 ~Kurt

On Tue, Jul 25, 2017 at 3:40 PM, Sherwin, Spencer J <s.sherwin at imperial.ac.uk<mailto:s.sherwin at imperial.ac.uk>> wrote:
Hi Kurt,

In the high order outflow condition the pressure appears as p n (where n is the normal) and has to be introduced in the relevant velocity component. So if your outflow is normal to the x-direction then the value of p n should appear in the Value of the u-variable.

Cheers,
Spencer.

On 24 Jul 2017, at 22:55, Kurt Sansom <kayarre at gmail.com<mailto:kayarre at gmail.com>> wrote:

Hi,
   I am trying to use the higher order outlet boundary conditions. I know that is formulated for truncated open domains, but am curious if I can use in the following way, where I want to specify the outlet pressure to some value to create back pressure in  the system. I realize that for in-compressible flow it doesn't matter that much, but I am interested in implementing a time varying pressure condition at the outlet.

 I have tried the following boundary condition for a tube and it doesn't appear to apply the VALUE tag? I want to make sure before I file a bug.


<REGION REF="2">
    <!-- Outlet , N=Neumann=gradient, D=Dierchlet=value R=Robin=mixed-->
    <N VAR="u" USERDEFINEDTYPE="HOutflow" VALUE="0" />
    <N VAR="v" USERDEFINEDTYPE="HOutflow" VALUE="0" />
    <N VAR="w" USERDEFINEDTYPE="HOutflow" VALUE="0" />
    <D VAR="p" USERDEFINEDTYPE="HOutflow" VALUE="10665" />
</REGION>

Regards,
 ~Kurt

--
Kurt Sansom
_______________________________________________
Nektar-users mailing list
Nektar-users at imperial.ac.uk<mailto:Nektar-users at imperial.ac.uk>
https://mailman.ic.ac.uk/mailman/listinfo/nektar-users

Spencer  Sherwin
McLaren Racing/Royal Academy of Engineering Research Chair,
Professor of Computational Fluid Mechanics,
Department of Aeronautics,
Imperial College London
South Kensington Campus
London SW7 2AZ

s.sherwin at imperial.ac.uk<mailto:s.sherwin at imperial.ac.uk>
+44 (0) 20 759 45052




--
Kurt Sansom

Spencer Sherwin FREng, FRAeS
Head, Aerodynamics,
Professor of Computational Fluid Mechanics,
Department of Aeronautics,
Imperial College London
South Kensington Campus,
London, SW7 2AZ,  UK
s.sherwin at imperial.ac.uk<mailto:s.sherwin at imperial.ac.uk>
+44 (0)20 7594 5052
http://www.imperial.ac.uk/people/s.sherwin/

-------------- next part --------------
HTML attachment scrubbed and removed