Solving force on a UDS - Fluent

Member

Hello, I am solving a UDS for a new pressure term. However, I cannot appear to solve the lift and drag force coefficients from this UDS on the airfoil I am simulating flow for, like you can with the pressure. I was wondering if it was possible to obtain the lift and drag from a UDS?

Alternatively can I obtain the normal vector on the airfoil and calculate the lift and drag from that or can I substitute P=UDS using the define adjust. I've tried these both with no success. Any help would be appreciated. Thank you.

Pierce

• GermanyForum Coordinator
edited January 15
You need to do the same Fluent is doing with the pressure variable when calculating the pressure forces. Area integral of the UDS along the surface in question. Use the area vector variable to get if as a force.
• Member
edited January 15
You need to do the same Fluent is doing with the pressure variable when calculating the pressure forces. Area integral of the UDS along the surface in question. Use the area vector variable to get if as a force.

Amine,

Thanks for the quick feedback. The surface integral of the UDS works. It's the second part of your statement I'm unsure of. The area vector variable, where can I access and use this to perform my calculation.

• GermanyForum Coordinator
edited January 15
Under mesh.
• GermanyForum Coordinator
edited January 15
You then dom pressure time x-face-area along surface to get pressure in x direction
• Member
edited January 15

Thanks worked great!

For anyone reading in future: In order to solve the Force on a UDS- create a custom field function: x-face-area * UDS/p_substitute , then perform a surface integral summation, this will give you the drag force.

• GermanyForum Coordinator
edited January 16
Please mark as is solved.