While modeling open channel flow in FLUENT5, once I cicked 'ok' on "Operating Conditions" in 'Define' menu with default values.

Next trial keeping all input data exactly the same as previous I DID NOT click on "Operating Conditions" in 'Define' menu.

But in both the cases I got the same velocity distrbution etc. So what is the Significance of the "Operating Conditions" ? How to set it OR use for flow of water in open channel subjected to atmospheric conditions?

>>>>While modeling open channel flow in FLUENT5, once I cicked 'ok' on "Operating Conditions" in 'Define' menu with default values.

>>>>Next trial keeping all input data exactly the same as previous I DID NOT click on "Operating Conditions" in 'Define' menu.

Actually you set the same op conditions in both of the cases. If don't open the op conditions panel, that means you are happy with the default setting !!

For some cases the Op conditions are to be set other than the defaults, e. g.,

A) U r using VOF, and the reference point has to be inside the primary fluid (low density fluid) B) The direction and value of g if you want to include the gravitational force.

DC