3 Replies Latest reply on Aug 11, 2010 4:27 PM by Nicholas Reynolds

    Drag Force of a Sphere

    Simon Watson
      I'm trying to estimate the drag force of a simple sphere using FloWorks 2008. The sphere is 0.15m in diameter and the fluid is water at 278K moving at 1ms-1.

      The tutorial about cylinder drag says that you should calculate the 'Component of Force' along a specified axis. If I do this for a sphere, the value is approximately half that which is expected (I've done the calculation by hand). If, however, you calculate the 'Normal Component of Force' as well as the 'Component of Force' and add the two together, you get the right answer.

      Why do I have to calculate both these components to get the right answer when the tutorial only specifies one of them?
        • Drag Force of a Sphere
          David Paulson
          Simon,

          With 49 looks at your post and no reply, I'd like you to know that you deserve an explanation. I have a current post that regards actual heat flow proidicted by Flow versus actual field measured values.

          IMHO, Flow in their manual and tutorial takes a cookbook approach to the analysis. Just follow the recipe and believe in the results. But when the actual results differ from the analysis.............what do you do???

          I think that the problem is that we needed to subscribe to the same thought process that the Flow programmers ascribe to. I think that much more description of the assumptions and method of calculation has to be part of the manual.

          The Flow manual provided by SolidWorks is extremely minimal considering the cost of the program.
          • Drag Force of a Sphere
            Anthony Botting
            Everyone: there is a wealth of technical information that is supposed to be installed by default with Flow Simulation. The documentation includes assumptions and methods of calculation, how it solves problems, tutorials and verification problems. Look in [installation drive and path]\SolidWorks Corp\SolidWorks Flow Simulation\lang\english\docs.
            • Re: Drag Force of a Sphere
              Nicholas Reynolds

              It is a year later and I am working on Solid Works 2010 and still having the same problem. I even tried this with many different shapes (squres, cones, and cylinders) at diferent speeds to see if I could find the problem but no luck.

               

              Nick