I am looking for a platform where I can plot the value of the drag coefficient of an airfoil for a range of Reynolds numbers (Cd vs Re plots). I wish to analyze the trend of Cd with changing Re and compare different airfoils based on the same. I tried:
Is there any other platform or software where I could get this? Some help would be really appreciated!
You had the right resource in airfoil tools but didn't use the comparison feature. Here are two airfoils as an example. To compare them go to the detail page for each and then click 'add to comparison' at the top right. You can select existing airfoils or add your own.
You will get a combined page with selection of Re for the airfoils selected. Pick the ones you want so as to limit complexity.
Then hit update plots and you get:
You have to use alpha as cd varies substantially with this, but the comparison is straightforward. In this example the blue lines are the two airfoils at re=50,000 and the brown/green are re=1,000,000.
XFOIL gives you several options, however, the X and Y axes will always be angle of attack or a coefficient. You can, for example, choose a Reynolds number (Re) which is variable with lift coefficient, so the resulting lift-drag plot is for a constant product of lift coefficient times velocity squared. The resulting drag coefficient at each lift coefficient then is valid for the same airplane at different speeds at the same altitude. There is no better way to compare two airfoils for the same airplane design.
If you desire to plot drag over Re, the lines would be valid only for one lift coefficient. It is more useful to plot several lines for the coefficients of lift and drag and to use Re as the parameter for the family of curves. Since friction drag changes roughly with the logarithm of Re, plotting is best done for magnitudes of Re (like 1, 2, 5, 10, 20 x 10⁶).
