1 Reply Latest reply on Oct 1, 2014 6:50 PM by Jared Conway

    Looking to find the torque caused by air flowing against a plate, GG torque help, flow simulation

    Bryan Cross

      FYI new to CFD and no one in my firm knows much about it......

       

      I am working on a model of a gimbal and looking at the air flow against the front cover of 250 ft/s.

      I want to know the torque required to hold the ball part of the gimbal in place. I did this and got some interesting answers that I didn't understand, using GG torque as a goal.

      So I went to an easier problem. Looking at the torque created by air flowing against flat plate 9'' x 10'' with at base larger then the computational domain. I again used GG torque as a goal and included pressure on front and back surfaces of the plate. The average torque I got was 2.1 ft*lb with an average pressure of 14.8 psi.

      Doing the calcs on this, the pressure and the torque created do not match up, not even close.

      (10'' x 9'') x (14.8 psi) x (4.5''/12) = 499.5 ft*lb

      Thinking that I don't fully understand the output of GG torque, help on this? And any help on how to find the torque to hold the plate still with 250 ft/s air flowing against it?

       

      Thanks in advance!

        • Re: Looking to find the torque caused by air flowing against a plate, GG torque help, flow simulation
          Jared Conway

          GG of torque will be for everything in the computational domain, i'd also recommend looking at a surface goal but there are caveats to that as well, make sure to check the help and the KB about what surfaces need to be selected.

           

          also remember that what you got using force and torque is highly dependent on mesh. so you may have to crank things up to get really good accurate results. and also consider vortices like the example in the tech references. you may have 2.1ftlb, but is that the fully converged solution or just one of the possible solutions.

           

          in this situation I always recommend starting with something with a known result and working from that before you work on something that is unknown. i'm not 100% sure that your calc will match the integration that SolidWorks simulation will be doing to calculate the torque. do other parameters like pressure, velocity, forces...etc match up? if the flow doesn't look good then it is unlikely that your torques will.