Simon Watson

Drag Force of a Sphere

Discussion created by Simon Watson on Mar 9, 2009
Latest reply on Aug 11, 2010 by Nicholas Reynolds
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?