it is difficult to compute 3d cl cd directly from cfd post, so export pressure distribution at partciular section ur looking for and then compute normal force and tangential force, from it calculate the Cl and Cd.  Try method called inverse BEM

Hi abdul,

Thanks for your kind reply.My PC configuration is i3, 500gb hard disk, 4gb ram, 1gb graphics card. 

Dear Abdul,

Thanks a lot for your kind information and your valid time for this.I will try to find and solve my case. If in case i have any doubts i will write it here.

Dear Abdul,

Once again thanks for such precise information.

I assume that you already can calculate the coefficients for the existing angle of attack. Now for a different angle of attack, you simply need to change the direction of flow. This can be done by creating a new plane with the required angle then originate the flow from that new plan instead of the old plane.

Dear Osama :

Thanks for your valuable answer.

I am not familiar with ANSYS but if it will produce local pressures, you can integrate them chordwise using a spline curve to get 2D results, then integrate those spanwise to obtain 3D results for the lift, drag and pitching moment coefficients.

An experimental example is given in NASA TN D-6215, 1971 for the lift and pitching-moment coefficients using a traveling-cubic-curve-fit method.