[sukratu]

I am using sonicFOAM for a not very unsteady flow. I am using a 3D geometry for aerospace applications. The solver is working on the case and appears to be giving
proper screen messages. Now I wanted the aerodynamic coefficients and realized
that the controlDIct file has lines which make the solver record only lift, drag and moment coefficients, which may be used for 2D geometries. There are however, six such
coefficients in all for me with my 3D case. Nobody seems to have required all six, perhaps! I did not find anything regarding that on the net! Any help would be appreciated.

[hk318i]

Sorry but your question is not clear, which coefficients you want to compute?
Generally, If they are direction based, just define new forceCoeffs functionObject with different directions. OR you could develop new function object for that.
Otherwise if you are looking to compute different coefficients based on force type, you can define in controlDict forces functionObject and calculate the coefficient based on these pressure and viscous forces. Also it is possible to develop new functionObject for this purpose.

[sukratu]

I need to calculate the following aerodynamic coefficients:
Drag Coeff.(C_D)
Lift Coeff.(C_L)
Side Force Coeff. (C_S)
Rolling Moment Coeff. (C_l)
Pitching Moment Coeff.(C_m)
Yawing Moment Coeff. (C_n)

The syntax for the lines to be included in controlDict for lift and drag
seem to be

liftDir (1 ,1 ,1 );
dragDir (1,0,1);

and there is a line to take in the pitching axis

pitchDir (0,0,1) ;
which presumably give the direction about which the moment of the "moment" coefficient in two dimensions is calculated.

(Please ignore the details of the directions above. I have cooked them up just to
explain which lines I mean)

Now do I simply say something like

yawDIr (0,1,0);

to obtain the yawing coefficient ?

Or will I have to ask the solver to give me force components and moment components
in a file and obtain the coefficients separately by shell scripting and formulae code files? Right now, that seems to be the best option for me. But something like

sideforceDir (1,0,0);

would be fabulous

[sukratu]

Sorry it is not pitchDir but pitchAxis.

[sukratu]

Apparently this works. Will try it over tomorrow and post back on this thread.

http://www.cfd-online.com/Forums/ope...ecoeffs-c.html

[hk318i]

Without even modifying the source code you can define two functionObjects for coefficient in controlDict with different directions and axis.

[sukratu]

Will try that as well.

[sukratu]

We seem to get problems during wmake. I have mentioned those in the following thread

http://www.cfd-online.com/Forums/ope...tml#post561195