# Difficulty in simulating pressure driven flow using pimpleFoam

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 March 2, 2021, 00:47 Difficulty in simulating pressure driven flow using pimpleFoam #1 New Member   parth Join Date: Feb 2020 Posts: 23 Rep Power: 6 Dear community, I am very new to OpenFOAM as well as to CFD. I am trying to simulate pressure-driven flow (geometry is similar to an inverted L shape, where the inlet is at the bottom), where we apply time-dependent pressure at the inlet and measuring the mass flow rate at the outlet. While I am able to run the simulation without any error. However, the outlet mass flow rate is 2 orders lower than lumped simulation. Here, I have taken sodium as working fluid (however I assume that wont make any difference, since I have divided the pressure with the sodium density, and provided appropriate viscocity in transport properties.) I would be grateful if any of you can point out where I am doing wrong. My velocity and pressure boundary is as follows: Velocity boundary conditions: Code: ```dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { inlet { type pressureDirectedInletOutletVelocity; inletDirection uniform (0 0 1); value uniform (0 0 0); } walls { type noSlip; } wedge1 { type symmetry; } wedge2 { type symmetry; } top_walls { type noSlip; } outlet { type pressureInletOutletVelocity; value uniform (0 0 0); } interface3 { type empty; } interface4 { type empty; } }``` Pressure boundary conditions: Code: ```dimensions [0 2 -2 0 0 0 0]; internalField uniform 0; boundaryField { inlet { type uniformTotalPressure; p0 table ( ); } outlet { type totalPressure; p0 uniform 0; value uniform 0; } walls { type zeroGradient; // type fixedFluxPressure; // value uniform 0; } top_walls { type zeroGradient; // type fixedFluxPressure; // value uniform 0; } wedge1 { type symmetry; } wedge2 { type symmetry; } defaultFaces { type empty; } interface3 { type empty; } interface4 { type empty; } }``` Transport properties: Code: ```transportModel Newtonian; // Laminar viscosity nu 2.16e-04; // Thermal expansion coefficient beta 3.0164e-4; // Reference temperature TRef 873; // Laminar Prandtl number Pr 0.0044; // Turbulent Prandtl number Prt 0.85;```

 Tags mass flow rate, pimplefoam, pressure driven flow