# Flow Direction: normal to boundary!!!

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 June 26, 2007, 07:48 Flow Direction: normal to boundary!!! #1 Atit Guest   Posts: n/a My current simulation is the flow between circular flat plate(both plates lie parallel to X-Z plane). The continuous flow of air flows in radially from the perimeter towards the center of the plate where there is the outlet. I specified 'INLET' with zero total pressure, flow direction: normal to boundary condition, and static temp=308K at the inlet position of the domain. After the computation, I found in CFX-Post that there is the Y-component of velocity at the inlet surface. This could not be possible, couldn't it? 'cause Y axis lie parallel to the inlet surface!!! Then I change the flow direction at inlet position in CFX-Pre to that FLOW DIRECTION: Option = Cylindrical Components Unit Vector Axial Component = 0 Unit Vector Theta Component = 0 Unit Vector r Component = 1 AXIS DEFINITION: Option = Coordinate Axis Rotation Axis = Coord 0.2 (this is Y axis) However I still have the Y-component of velocity at the inlet surface. Do anybody know what wrong with this? Does 'flow direction: normal to boundary' really mean that there must be no flow in parallel direction of the surface? Thank you for your consideration. Atit

 August 2, 2015, 14:42 #2 New Member   Join Date: Jul 2015 Posts: 13 Rep Power: 10 Hi Atit, I know it's been eight years but did you ever manage to solve this problem? I am having a similar issue.