To fix the issue, you need to ensure that the area selected in CFD-Post matches the area selected in Fluent. Here are the steps you can follow:

  1. In Fluent, make sure that the inlet boundary condition is defined correctly with the correct dimensions for the inlet.

  2. Check the inlet surface area in Fluent by selecting the inlet surface and looking at the surface area value in the surface integral in the result section

  3. In CFD-Post, select the inlet surface and make sure that the surface area matches the value in Fluent.

Can you please share values of area you are getting in fluent and CFD post?

Thank you