Incorrect Results from x and y velocity components in terms of Angle of attack

- October 8, 2025 at 11:26 pm
  
  muhammadfaraz.mahmood
  Subscriber
  
  When I rotate the aerofoil in 2D simulation and give inlet velocity in just x axis, the lift and drag forces are coming correct.
  
  However, if I leave the aerofoil at 0 degree AOA, and change the velocity into x and y component through cos and sin (AOA), the results are not coming correct.
  
  I have tried meshing in C type, but still cant figure out where is the problem, I mean dont understand why my x and y component velocities are giving wrong results. I have been trying since 2 months but couldnt figure out. I hope if some one can guide me.
  
  Thanks
- October 9, 2025 at 8:03 am
  
  Petros
  Ansys Employee
  
  Hello, have you used the correct force vectors for the report definitions in the second case?
- October 9, 2025 at 8:52 am
  
  muhammadfaraz.mahmood
  Subscriber
  
  These are all inputs from fluent that I am using. The main velocity is 33.68 m/s. After putting sin and cos to it, it changes to the mentioned values in the attached image. I wonder if I am correct in these given inputs but missing something else
  - October 9, 2025 at 9:21 am
    
    Petros
    Ansys Employee
    
    As said, you need to use the correct values for the force vector in the lift report definition panel. In order for the 2 setups to agree, the x and y components have to be taken at the correct coordinate system.