Using pressure specified boundaries in natural con

Atit Koonsrisuk

I am using CFX5.5.1 to simulate the laminar flow over the constant temperature vertical flat plate. Air at STP is the fluid domain. The vertical distant of the plate is 10 centimeter. Then the hydrostatic pressure due to the weight of fluid is about 1.16 Pa. The temperature of the plate is 500K and the surrounding fluid is 300K.

I set the condition at inlet position as zero reference total pressure; and specify 1.16 Pa as the reference static pressure at outlet boundary. The velocity profile obtained is wrong. The velocity outside the boundary layer is higher than inside's. Then I change the outlet boundary condition to zero reference static pressure. This time, the velocity profile gained seem reasonable.

I do not agree with the results. In the real world, there is that 1.16 Pa at the outlet. I think I might make some thing mistake. Do anyone have an idea?

Thank you very much.

Atit