We are trying to model a flat paddle mounted on a large flat plate perpendicular to the direction of flow. The main reason for the analysis is to determine the force on the plate and how far behind the paddle the flow will remain turbulent. We used Gambit to create the paddle and tunnel for the flow. The tunnel is square and the paddle is sticking out of the middle of one of the walls. The tunnel cross section area is roughly ten times that of the paddle. We have a velocity inlet and a pressure outlet on either end of the tunnel. We are having trouble getting our analysis to converge in Fluent. The residuals go down to about .01 but never any lower for any of the viscous models. Is this sufficient or should they be lower. We are using unsteady solver because of the turbulent flow. Any suggestions on our Gambit model, mesh, or what settings to use in Fluent (we are using all defaults other than material, viscous model, and solver) or anything else would be of help.

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