SimScale CAE Forum

Setting of Drag Coeffect of building

I tried setting up the drag coefficient settings for a tower. Based on the documents provided by Simscale, I arrived at the results shown in the figure below.

  1. Does anyone have experience with this problem tell me if the settings are correct or not?
  2. In case the tower was a cylinder, how can we define the Reference area value, please?

Hey there!

Your setup is almost there, just a few points to review:

  • Center of rotation: Has no effect on the lift and drag, but on the moments. Be aware that yours it not on the centroid of the building.
  • Lift and drag directions: this setting is sensitive to the sign of the vector, so please be aware of negative and positive directions.
  • Reference length: there are many possible definitions of this value, which is used to compute the Reynolds number. Refer to literature and be consistent!
  • Write control: this determines the number of points in the output curve.

For the case of a cylinder, I would suggest you to also refer to literature. A very useful mental picture is that the area is the shadow casted by the overall flow.

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Hi @ ggiraldof,
Thank you for your review,
About the lift and drag direction, I know they are interchangeable based on the object and direction of the wind. But, in the case of the building shown above, Drag is related to the direction of the wind (X axis) and Lift with the Z axis, so is that correct?