Hi !! I will use CFX 5.4.1 to simulate the flow behavior of the flow in the pipe that submerge under water 0.3 m. I don't undetstand I can use outlet of pipe with average pressuer (rho*9.81*0.3) Pa on outlet boundnary condition. what you think??

Thank you

Tol na Deen

This is a very good example. If pipe's diameter is less, I mean if the variation of the pressure across vertical diameter of the pipe is within your prescribed limit, you can accept little error. But this will not give very correct result. The centre of pressure acting on the pipe cross section will be on the vertical partition and at depth of 2/3 diameter. Its value is Max pressure (rho*9.81*h)(h is lower most point of pipe c/s) divided by two. In CFX you can give such boundary condition directly. Software will do the rest. No need to give uniform average pressure.

thank you sheetal , Mon My diameter is 400 mm.