# [momentumPredictor] Frozen velocity field

 Register Blogs Members List Search Today's Posts Mark Forums Read

 October 10, 2023, 08:39 [momentumPredictor] Frozen velocity field #1 New Member   Dasha Join Date: Sep 2023 Posts: 15 Rep Power: 2 Hello everyone, Can someone tell me how to turn off the equations for the momentum for "foamMultiRun"? I calculated the pre-initiated field of velocities and pressures. Now I want to calculate my case with only heat transfer. I turned off the flow equations in fvSolution. When I start running the case, the velocity are not calculated in residuals, but the velocity field still changes. Please someone tell me what could be the problem? fvSolution: Code: ```PIMPLE { flow off; momentumPredictor off; nOuterCorrectors 30; nCorrectors 1; nNonOrthogonalCorrectors 0; ...``` physicalProperties: Code: ```thermoType { type heRhoThermo; mixture pureMixture; transport const; thermo eConst; equationOfState rPolynomial; specie specie; energy sensibleInternalEnergy; } mixture { specie { molWeight 18.015; } equationOfState { rho0 1000; T0 278; //beta 2e-04; C (0.001278 -2.1055e-06 3.9689e-09 4.3772e-13 -2.0225e-16); }``` from log file: Code: ```wedge0_rotated diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 wedge0_rotated DILUPBiCGStab: Solving for e, Initial residual = 0.000680102566017, Final residual = 5.34837357105e-05, No Iterations 1 wedge0_rotated DICPCG: Solving for p_rgh, Initial residual = 0.00296039703522, Final residual = 9.69628888453e-09, No Iterations 595 wedge0_rotated diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0 wedge0_rotated time step continuity errors : sum local = 1.40253056235e-10, global = -7.49192173107e-13, cumulative = -8.68144446708e-09```

 November 6, 2023, 08:26 #2 New Member   Join Date: Mar 2022 Posts: 7 Rep Power: 4 Hi, make a minIter 0 for fluid in fvSolution, except for pressure (but I'm not sure)

 November 15, 2023, 05:56 #3 New Member   Dasha Join Date: Sep 2023 Posts: 15 Rep Power: 2 After testing different configurations, I would like to share my observations and conclusions: The problem was in the equations of state. I considered a compressible fluid in my case, which is why the velocity field could not remain the same as in the case of an incompressible fluid. So I came to the conclusion that we cannot simultaneously consider a compressible fluid and an unchanging field of velocities and pressures.

 Tags frozen flow, momentum equation, velocity field