Calculated torque value not matching with fluent value
 

Hi everyone

I am a student, recently gained intrest in CFD and started working on small cases to learn and understand tool and physics.

I have been working on a simple case of "transient simulation, Flow over a rotating circle -2D". I am using pressure inlet and outlet as boundry conditions, with constant RPM. My challenge is i am not able to match calculated torque value and fluent torque value. Also I have observed that torque value is changing with time even tough with constant RPM

Need help to figure out my case. Thanks in advance

If you want help, you have to share some more details.

At minimum:
-which pressures and flow rate did you use?
-what is the torque value calculated by you?
-how did you calculate that?
-what is the torque value calculated by fluent?

Hi Pakk,

Thanks for your reply, my apologies for not giving complete information.

I have used simple model of (R)0.07m circle in a rectangular domain, Circle rotating with 1780.23 rad/sec. I have used KOmega solver with boundry condition (Pressure inlet and pressure outlet) in transient case and ran for 4 sec, ANSYS torque value is 19Nm.

I have theoretically calculated torque value by (Moment of inertia of circle (I) X Angular acceleration (Alpha)) and the derived value is 0.008Nm.

I am not able to understand where i am going wrong.

Thanks for asking me :-)