I'm trying to figure out how surface variable loads are defined by functions in a cylindrical coordinate system.
I tried a simple test. Make a cylindrical coordinate system with the origin at the top of the tank, and the positive Z pointing to the bottom.
![Cylindrical Coords.png Cylindrical Coords.png](https://forums.autodesk.com/t5/image/serverpage/image-id/90756i2364B91FA02FA1CA/image-size/original?v=mpbl-1&px=-1)
I then applied a surface variable load to the shell wall. The function is R = s, therefor the pressure should increase from 0 to 6.3 as it goes around the tank.
![Surface Variable Load Options.png Surface Variable Load Options.png](https://forums.autodesk.com/t5/image/serverpage/image-id/90758i1237F3ED22682255/image-size/original?v=mpbl-1&px=-1)
The Variable Load Viewer confirms what I want to achieve.
![Variable Load Viewer.png Variable Load Viewer.png](https://forums.autodesk.com/t5/image/serverpage/image-id/90760i94B609230B3108E2/image-size/original?v=mpbl-1&px=-1)
But when I run the model, the pressure increases to pi radians (180 deg) in the positive and negative directions.
![Results.png Results.png](https://forums.autodesk.com/t5/image/serverpage/image-id/90762i64FCFE3B3FEED941/image-size/original?v=mpbl-1&px=-1)
I was expecting it to steadily increase positively all around the tank.
Anybody have an Idea why it splits?