when i turn the cartesian to cylinder coordinate, the second one: angle=atan(y/x),but this error come out:

INTERNAL Internal error detected: Error in ic_calc: PROBLEM ENCOUNTERED WHEN EXECUTING CFX EXPRESSION LANGUAGE

The CFX expression language was evaluating:

"Input from CFX-5"

The problem was:

DIVIDE-BY-ZERO

FURTHER INFORMATION

The problem was encountered in executing the expression for:

angle The complete expression is: atan(y/x) The error occurs on sub-expression: y/x

BACKGROUND INFORMATION

The error was detected at one location. The same problem may be present at other locations - that has not been investigated. The following values are for the first location which has the problem.

Solver obviously doesn't like this idea when x=0. Your may need to isolate this, and make a condition to overcome the problem.

thanks for your replying this yes,i can see this x=0 point,but,could you tell me how to avoid this happen?and how to define that X=0 point,

and to solve this problem,what can i do next? or maybe you can introduce some books or techn i can read.

thanks in advance