[Nek5000-users] Different velocity values in different 'v' inlets

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

Usually this is the element number.


For example:


      subroutine userbc(i,j,k,eg)

      integer e,eg


      real myux(lxl1,ly1,lz1,lelt)

      common /mystuff/ myux


      e = gllel( eg )  !  Convert global element number to element number local to this rank


      ux = myux(i,j,k,e)


      etc.


      return

      end


would assign your own ux() ["myux"] array values to the boundary points wherever

a Dirichlet condition ("v  ") has been assigned.


hth,


Paul


________________________________
From: Nek5000-users <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: Sunday, December 31, 2017 1:18:06 PM
To: nek5000-users at lists.mcs.anl.gov
Subject: Re: [Nek5000-users] Different velocity values in different 'v' inlets

What is the variable e in userbc?

On 31 Dec 2017, at 19:35, "nek5000-users at lists.mcs.anl.gov<mailto:nek5000-users at lists.mcs.anl.gov>" <nek5000-users at lists.mcs.anl.gov<mailto:nek5000-users at lists.mcs.anl.gov>> wrote:

Hi all,

I'm trying to simulate a shear-layer which involves two different jets emerging at different velocities. The simulation is 2D for now. The width of the first jet extends from y=0.0 to y=1.0 and the second extends from y=1.0 to y=3.0

I generated a mesh using genbox with 'v' BCs for both inlets.

In the .usr file I have the following form for usrbc

 subroutine userbc (ix,iy,iz,iside,ieg)
c     NOTE ::: This subroutine MAY NOT be called by every process
      include 'SIZE'
      include 'TOTAL'
      include 'NEKUSE'
      if (ym1(i,j,k,e).lt.1) then
          ux=10.0
      elseif (ym1(i,j,k,e).gt.1) then
          ux=1.0
      endif
      ux=1.0
      uy=0.0
      uz=0.0
      temp=0.0
      return
      end

As you can see I try assigning ux = 10.0 and 1.0 to the different zones. However the results show a uniform value of 1.0 across both the inlets.
What am I missing here?

Sincerely,
--

Amitvikram Dutta

Graduate Research Assistant

Fluid Mechanics Research Lab

Multi-Physics Interaction Lab

University of Waterloo

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