# Spanwise Pressure Coefficient Distribution of Rotating Wind Turbine Blade

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 March 16, 2021, 05:51 Spanwise Pressure Coefficient Distribution of Rotating Wind Turbine Blade #1 New Member   Niall Whelan Join Date: Mar 2020 Posts: 2 Rep Power: 0 Hi, I'm currently working on a Star CCM+ model of the NREL Phase VI wind turbine for validating a VLM code. I have everything complete and all reports and residuals converge well but I am trying to compare the pressure coefficient distribution at various span wise locations of the turbine blade from the CFD model to the experimental data. My problem is that the experimental data is normalised along the chord from zero to one and my CFD data is using [0 1 0] direction and as the leading edge of the blade isn't coincident with y=0 and the blade is twisted I am not able to properly compare the results. How does one plot the pressure coefficient data against a direction that is from the leading edge to the trailing edge in Star CCM+ for a rotating twisted blade? Thanks in advance! Regards, Niall

 March 16, 2021, 08:40 #2 Senior Member   Matt Join Date: Aug 2014 Posts: 931 Rep Power: 16 This request is not totally clear. Are you asking how to plot cp distribution around the airfoil shapes at different spanwise stations along the rotor?' You can create derived parts (probes/lines) that snap to a surface that are defined in a local coordinate system. The help material is very useful in this regard.

 March 16, 2021, 08:45 #3 New Member   Niall Whelan Join Date: Mar 2020 Posts: 2 Rep Power: 0 Thanks for your reply! Sorry if I am being unclear! I have been successful in setting up the derived parts and the Cp plot however, when I plot the pressure distribution data in Star CCM+ the X-axis uses a vector direction of [0 1 0] which is not representative of a rotating twisted blade. I am looking to figure out how to set up the x axis of the x-y plot so that it is parallel with blade chord and that zero on the x-axis would align with the leading edge of the blade at a given span-wise location? Hope this is clearer! Thanks again!

 March 16, 2021, 12:38 #4 Senior Member   Matt Join Date: Aug 2014 Posts: 931 Rep Power: 16 Create a local coordinate system at each station that is aligned with the chord direction and centered at the leading edge. Then you can create field functions to define a normalized position (x/c, y/c, z/c) vector for each station that references the local coordinate system you created.

 March 16, 2021, 12:39 #5 Senior Member   Matt Join Date: Aug 2014 Posts: 931 Rep Power: 16 duplicate post deleted Last edited by fluid23; March 16, 2021 at 12:41. Reason: duplicate post