# simpleFOAM (RANS) - internal pipe flow - 'k'

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April 24, 2018, 13:41
simpleFOAM (RANS) - internal pipe flow - 'k'
#1
Senior Member

Guilherme
Join Date: Apr 2017
Posts: 194
Rep Power: 8
Hello,

First, I'm using OpenFOAM 5.0 (RANS - realizebleKE):

Re=5300 (R = 0,00635 - L=4D)

BC:
Quote:
 pipe_wall epsilon internalField uniform 0.00952; { type epsilonWallFunction; value uniform 0.00952; } k internalField uniform 4.5e-3; { type fixedValue; value uniform 1e-15; } OBS: Using kLowReWallFunction I'm having the same problem. nut internalField uniform 0; { type calculated; value uniform 0; } p internalField uniform 0; { type zeroGradient; } U internalField uniform (1 0 0); { type fixedValue; value uniform (0 0 0); } cyclic domain log: ... Time = 1500 smoothSolver: Solving for Ux, Initial residual = 8.14155e-05, Final residual = 7.41441e-06, No Iterations 3 smoothSolver: Solving for Uy, Initial residual = 7.04818e-05, Final residual = 3.22128e-06, No Iterations 3 smoothSolver: Solving for Uz, Initial residual = 5.7334e-05, Final residual = 3.25325e-06, No Iterations 3 Pressure gradient source: uncorrected Ubar = 0.999999, pressure gradient = 1.05028 GAMG: Solving for p, Initial residual = 0.000159464, Final residual = 1.44095e-06, No Iterations 2 time step continuity errors : sum local = 1.32913e-07, global = -2.98883e-10, cumulative = -4.11386e-07 Pressure gradient source: uncorrected Ubar = 1, pressure gradient = 1.04501 smoothSolver: Solving for epsilon, Initial residual = 5.50983e-05, Final residual = 4.04455e-06, No Iterations 2 smoothSolver: Solving for k, Initial residual = 5.71171e-08, Final residual = 5.71171e-08, No Iterations 0 ExecutionTime = 1851.33 s ClockTime = 2205 s yPlus yPlus write: writing object yPlus patch pipe y+ : min = 0.973688, max = 1.13078, average = 1.06766
I started a simulation using the realizableKE model in order to compare it to my kOmegaSST simulation (whose convergence). I noticed that when starting the simulation, the values of 'k' assume the following pattern (attached image), could someone advise me on what to do in relation?
Attached Images
 OF.jpg (42.7 KB, 24 views)

 May 15, 2018, 07:17 #2 New Member   JD Join Date: May 2017 Posts: 24 Rep Power: 8 So, I have a question about your question. Given that you're using wallFunctions, wouldn't you want your y+ to be between 30 and 300?

 Tags openfoam, rans, realizableke, turbulence kinetic energy