↑top

XSim User manual

Output aerodynamic coefficients (Cd, Cl etc...) in specified region

Updated: June 25, 2019

You can output aerodynamic coefficients (Cd, Cl etc...) in specified region by following steps.

  1. Select "Region" tab on "Output" page.
  2. In "Region", select the region where you want to calculate aerodynamic coefficient, and in "Type", select "Force coefficients".
  3. Enter drag direction, lift direction, reference velocity, reference length and reference area as parameters.

    Push Preview to preview the directions of drag/lift on 3D view.

    You can measure the projection area of the shape with XSim. Push measure projection area to show the tool.

    Feature to measure projection area
    Feature to measure projection area
  4. Push Set button to make an output-setting.
    Region tab on Output page
    "Region" tab on "Output" page
  5. If you delete the setting, push × at upper-rigt corner of the setting (blue rectangle).

The data will be output as a text file such as the followings in the postProcessing directory in the OpenFOAM case directory.

# Force coefficients
# liftDir     : (0.000000e+00 0.000000e+00 1.000000e+00)
# dragDir     : (1.000000e+00 0.000000e+00 0.000000e+00)
# pitchAxis   : (0.000000e+00 -1.000000e+00 0.000000e+00)
# magUInf     : 1.000000e+00
# lRef        : 1.000000e+00
# Aref        : 1.151719e-01
# CofR        : (3.369437e-01 2.145408e-05 7.275021e-02)
# Time        	Cm            	Cd            	Cl            	Cl(f)         	Cl(r)         
0.0142857     	3.482367e+00	9.417716e+01	2.737129e-01	3.619224e+00	-3.345511e+00
0.0265306     	1.642072e+00	9.428340e+00	1.088009e+01	7.082116e+00	3.797972e+00
0.0387755     	1.767928e+00	8.503763e+00	1.009278e+01	6.814319e+00	3.278463e+00
0.0510204     	1.765188e+00	8.140994e+00	1.027949e+01	6.904932e+00	3.374556e+00
0.0632653     	1.700287e+00	7.950298e+00	1.041909e+01	6.909830e+00	3.509257e+00
0.0755102     	1.708614e+00	7.900045e+00	1.065372e+01	7.035472e+00	3.618244e+00
0.0877551     	1.729580e+00	7.943610e+00	1.089946e+01	7.179312e+00	3.720151e+00
0.1           	1.716362e+00	7.826984e+00	1.107033e+01	7.251525e+00	3.818802e+00
0.1125        	1.758462e+00	7.783669e+00	1.122876e+01	7.372844e+00	3.855921e+00
・・・(省略)・・・

pitchAxis is a direction orthogonal to the direction of drag and the direction of lift. It is automatically defined by XSim. Cm is the torque coefficient around the pitch axis, Cd is the drag coefficient, and Cl is the lift coefficient. And Cl(f)=Cl/2.0 + Cm, Cl(f)=Cl/2.0 - Cm.

XSim User manual