[mathew1105]

Hi ,



i am simulating the flow over a pipe that has a hot cylinder and gets out to the atmosphere. As solver i am using buoyantBussinesqSimpleFoam, but i am having problems of stability and continuity errors. I have read i other forums and they have given solutions on the boundary Conditions of p_rgh for the pressure with bouyantPressure. The problem is that my version of Openfoam doesn't have this BC. I am simulating with a laminar model and with turbulence with turbulent model k-epsilon. But both simulations get unstable.


So in the other forums they said that the Bc of fixedFluxPressure replaced this BC. I adjusted the case with this, but in the laminar and RAS model, the simulation doesnt converge. my BC are as follow:


0/U


inlet > fixedValue; value (0.1 0 0)
outlet > inletOutlet; inletValue (0 0 0)
walls > noSlip;
cylinder > noSlip;


0/p_rgh


inlet > zeroGradient;
outlet > fixedFluxPressure; rho rhok ; value uniform 0;
walls > fixedFluxPressure; rho rhok ; value uniform 0;
cylinder > fixedFluxPressure; rho rhok ; value uniform 0;


0/T


inlet > fixedValue ; value 300;
outlet > inletOutlet ; inletValue uniform 300; value uniform 300;
walls > fixedValue ( except the down wall that is adiabatic so i used zeroGradient)
cylinder > fixedValue; value uniform 350


could someone please help me to find the error? , i would be very greatfull