[Nek5000-users] torque calculation on airfoil

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

Hi Sijo,


Torque should simply compute the torque in each direction about the 3 axes emanating from the point prescribed by the coordinates of X0.


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: Friday, June 22, 2018 6:20:05 PM
To: nek5000-users
Subject: [Nek5000-users] torque calculation on airfoil

Hello Neks,

Finally I was successfully able to import mesh from ICEM to Nek5000 with periodic BCs. Now I have to set up a fluid structure interaction code in NEK5000.

The test case is called self sustained pitching of an airfoil. For that I had to calculate torque about the Elastic Axis(EA). I know that using toque_calc function I can calculate torque in x and y direction.

But I am bit confused with the input parameters for this function.

Here I show the code,

      real x0(3)
      save x0
      data x0 /3*0/


      x0(1) = 0.29016  !  X- Direction (Chord wise direction where chord length = 1.56)
      x0(2) =  0.0         !  Y -Direction
      x0(3) =  0.2         !  Z- Direction. (Span wise direction where total span width = 0.4)

      n = nx1*ny1*nz1*nelv

      if (istep.eq.0) call set_obj  ! define objects for surface integrals

       scale = 2.  ! Cd = F/(.5 rho U^2 ) = 2*F

      call torque_calc(scale,x0,.true.,.true.)

I just have to confirm that,

1) Here x0 is the Elastic Axis point right?

2) Am I correct with the Axis notations? (for example: x0(1) represents X direction?)

3)In fact, the simulation is 3D, but the thickness is just 0.4 and  there is no motion in Z direction. So, to calculate torque for pitching do I have to give the value for x0(3)? If yes is that okay if I give the midpoint in z direction?

Thanks in advance

Sijo GEORGE


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