| Author | Message | ||
     Iyad (ihijazi) New member Username: ihijazi Post Number: 1 Registered: 09-2005 |
I need to model a hollow cylinder with internal Pressure load. If I use Cartesian3 coodrinate system. how do I specify a uniform pressure load on the internal region? and how do I get the results in termas of (r,theta,z) | ||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 464 Registered: 06-2003 |
1. A uniform pressure load on the inner surface would be represented as "VALUE(P)=P0" applied to the inner bounding curve. If P is not a variable, then you have to apply a boundary condition to something that is a variable but reflects the same thing. 2. We have no mechanism for treating 3D cylindrical coordinates directly. A couple of things occure to me: a) Unwrap the cylinder and treat (r,z) as the baseplane coordinates and theta as the extrusion direction. Apply periodic boundary conditions at the top and bottom, and write the equations explicitly in the correct form for the geometry. Since the cylinder is hollow, you will not run into singularity troubles as you would if the model included the axis. b) solve the problem in cartesian coordinates and export r,theta,z and all variables to an external application that can plot them. Bear in mind that the built-in definition of "r" is sqrt(x^2+y^2+z^2), so you will need to redefine it to get the cylindrical radius. |