[Nek5000-users] Accessing the value of drag and lift coefficients in usrchk

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

Dear JC,

Yes --- just pull a copy of the common block out of torq_calc in navier5.f:



      common /ctorq/ dragx(0:maxobj),dragpx(0:maxobj),dragvx(0:maxobj)

     $             , dragy(0:maxobj),dragpy(0:maxobj),dragvy(0:maxobj)

     $             , dragz(0:maxobj),dragpz(0:maxobj),dragvz(0:maxobj)

c

     $             , torqx(0:maxobj),torqpx(0:maxobj),torqvx(0:maxobj)

     $             , torqy(0:maxobj),torqpy(0:maxobj),torqvy(0:maxobj)

     $             , torqz(0:maxobj),torqpz(0:maxobj),torqvz(0:maxobj)

c

     $             , dpdx_mean,dpdy_mean,dpdz_mean

     $             , dgtq(3,4)

c


There you have access to all components, including breakdown into pressure and viscous
contributions.

If you have only one object (or surface),

      dragx(0) = force in x direction  (typ., = drag)
      dragy(0) = force in y direction (typ., = lift)

If you have multiple objects/surfaces, then dragx(k)=force in x direction on object k, k=1,...
and dragx(0) = sum_k=1,.. dragx(k)

Paul

________________________________
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, March 30, 2017 3:33 AM
To: Nek 5000
Subject: [Nek5000-users] Accessing the value of drag and lift coefficients in usrchk

Hi Nek,

I was wondering whether it was possible to access the values of the drag and lift coefficient directly into usrchk?
I know how to compute them but they only get printed in the logfile. I would need them for a control problem.

Thanks a lot

Jean-Christophe B. Loiseau
Maître de conférence
DynFluid, Arts et Métiers ParisTech

Homepage<https://sites.google.com/site/loiseaujc/>

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