CFD results aren't matching observed values

[Anonymous]

Hello,

I am trying to setup a CFD analysis to evaluate convergence plot, boundary conditions and wall force calculators for a propeller, all three of which are not matching with the experimental values (observed).

We were trying modify the model, if we can get near to the experimental values we are right now using rotating region and giving time steps for calculation of the forces acting on the propeller. Is there any other way to calculate the wall forces besides rotating region.

     Thanking you in advance

[matt.bemis]

Hi @Anonymous,

Thanks for reaching out to us on the forums! Are you referring to the Rotating Region results file? This had hydraulic torque, time, and rpm for every time step- it is incredibly useful. This information can also be accessed via a csv file in the solver folder. 

Have you seen this webinar on rotating regions? The webinar is incredibly useful and basically contains all the information you need to know. I've watched it several times myself. 

How far off are you results? 

Thanks,

[Anonymous]

Hi thanks for the reply,

What we were encountering is deviation of thrust (we used wall calculator to check the values at the below of the rotating region boundary),

the deviation ranging from 45grams to 70 grams compared to experimental values being nearly 500 grams overall thrust.

And the mesh layers, in transient mode i was not able to switch on the adaption for refinement, and also the pressure seems correct on the wings, my thoughts are i thinks we are not able to get the net results or vectors we require, is there a way to get custom results at monitor points, and is there a specific way to get the force exerted by the output fluid after the propeller rotation.