[Nek5000-users] torque calculation on airfoil

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

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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