[peter969]

I'm a long-time lurker, first-time poster, so I should start by thanking the contributors to this forum for knowledge that I have pilfered in the past!

I am trying to simulate (in steady-state) the flow around a vehicle when it's travelling around a corner. Initially I am simply considering a 2D scenario with a semi-circular annulus (see hastily-drawn picture), and a brick representing the vehicle.

As the picture shows, I want to create the flow field by applying a Domain Rotation about the axis of the annulus, with fresh mass-flow being added at the inlet, and the wake of the brick being removed at the outlet.

The inner/outer radial walls have been defined as free slip walls, but I'm unsure about the inlet and outlet. My (not necessarily correct) logic tells me that I should specify Total Pressure = 1atm at the inlet, and Static Pressure = 0atm at the outlet .The user guide seems to indicate that using 'Opening' boundaries is the best way of doing this.

However, while this gives feasible forces and total pressures, the radial velocity distribution across the annulus is far away from the linear profile one would expect upstream of the brick, and is in some areas an order of magnitude larger!
When I specify the inlet as Static Pressure = 0atm, the velocity distribution is much more valid, but the total pressures (and consequently forces) are wrong; in the wake of the brick, Ptotal is apparently negative!

If anyone is able to shed any light on why I my BCs may not be giving me what I expect, I would be very grateful.

Pete

(I should mention that I'm using CFX within Ansys Workbench V12, on Windows).