[MJ55]

Hi there,

I need to help creating an expression for a CFX Pre case I am modelling.

I want to create a variable bouyancy force along a specified axis of a geometry.

To explain better a picture of the geometry is included below


Uploaded with ImageShack.us

You can see my rectangular geometry, I want to have a steadily increasing buoyancy force along the z axis of the geometry.

The length of the geometry is 0.5 metres.
The function I would like to input is

y = 200*x

Where y is the buoyancy force and x is the distance along the z axis of the geometry.

My problem is that I have no idea how to input the body's z axis distance as a variable.