[nived]

Iam doing a work on the study of temperature profiles in the proximity of bundle of heated pipes arranged above each other. The flow is laminar and natural convection.
As it is natural convection, i need the velocity at inlet to be zero. Iam applying pressure boundary conditions at both inlet and outlet. I gave the pressure at both inlet and outlet as atmosphere pressure. But when i check the velocity vectors, it is showing some amount of velocity at inlet. How to make this velocity zero? Please find the mistake i made....
Iam attaching the image of my geometry.

[LuckyTran]

Use a velocity inlet. Set the velocity to 0.

[nived]

How can i do the same with pressure inlet boundary condition?

[obscureed]

Hi Nived,


Can you explain why you want to use a pressure inlet? Or maybe explain more carefully what you want in terms of zero velocity?



From my perspective, if you want to specify a zero velocity, then you should define a velocity inlet, as LuckyTran suggests. You cannot specify both velocity and pressure -- one defines the other. (Another option would be a wall -- the difference being that a wall allows some flow in the plane of the wall, at least a cell's width or so away. A velocity inlet with zero velocity in all coordinates will also resist cross-flow, so the effect will be similar after a few cells. A wall may be marginally more stable.)


Best regards,
Ed

[nived]

If i give velocity inlet and pressure outlet , what should be the gauge pressures at the inlet and outlet?
I need to specify zero velocity at inlet as it is natural convection....is there any mistake?? Pls help