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Old   November 7, 2008, 10:24
Default Just a precision: imposing no
  #21
ep4
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Pattyn Eric
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Just a precision: imposing no boundary condition for temperature at the Outlet would mean for me to use a "calculated" condition.
When trying to use it, i receive the following error:

Starting time loop

Courant Number mean: 0.00606061 max: 0.133333
Time = 0.0005

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Ux, Initial residual = 1, Final residual = 1.13964e-06, No Iterations 3
DILUPBiCG: Solving for Uz, Initial residual = 0.999969, Final residual = 2.03988e-07, No Iterations 4



gradientInternalCoeffs cannot be called for a calculatedFvPatchField
on patch Outlet of field h in file "/net/ric_home/ep4/OpenFOAM/eric-1.5/run/Flatplate_no_buoyant_unstaedy/0/h"
You are probably trying to solve for a field with a default boundary condition.

From function calculatedFvPatchField<type>::gradientInternalCoef fs() const
in file fields/fvPatchFields/basic/calculated/calculatedFvPatchField.C at line 187.

FOAM exiting
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Old   November 7, 2008, 11:13
Default Hello Eric, Quoting from y
  #22
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Prashant Ojha
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Hello Eric,

Quoting from your post:

"It appears me logical tu use a fixed temperature at the inlet and the plate, a zeroGradient condition at the boundary Up (infront of the plate)."

Thats right, I take back my words. I misread your earlier post and had a completely different case in my mind while replying.

Well, I am retiring for the day but I would like you to check the following boundary conditions.

p:

internalField uniform 100000;

boundaryField
{
WallDown
{
type calculated;
value uniform 100000;
}

Inlet
{
type zeroGradient
}

Outlet
{
type zeroGradient;
}

Up
{
type zeroGradient;
}
}

// ************************************************** *********************** //

pd:

dimensions [1 -1 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
WallDown
{
type fixedFluxBuoyantPressure;
value uniform 0;
}

Inlet
{
type fixedValue;
value uniform 50;
}

Outlet
{
type fixedValue;
value uniform 0;
}

Up
{
type fixedValue;
value uniform 0;
}
frontAndBack
{
type empty;
}
}

// ************************************************** *********************** //


T:

dimensions [0 0 0 1 0 0 0];

internalField uniform 300;

boundaryField
{
WallDown
{
type fixedValue;
value uniform 300;
}

Inlet
{
type fixedValue;
value uniform 300;
}

Outlet
{
type zeroGradient;
}

Up
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}

// ************************************************** *********************** //


U:

dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
WallDown
{
type fixedValue;
value uniform (0 0 0);
}

Inlet
{
type fixedValue;
value uniform (10 0 0);
}

Outlet
{
type zeroGradient;
}
Up
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}

// ************************************************** *********************** //
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Old   November 7, 2008, 11:33
Default You were right, setting turbul
  #23
ep4
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Pattyn Eric
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You were right, setting turbulence off and the simulation is ok. However, i don't know what i should do in order to use the kEpsilon model. Change my initial values for k and epsilon? I had followed the example in tutorial (User guide U-41).

Is it possible that the initial values of epsilon and k influences my results (it can diverge!) even if i have set teubulence off??

Thanks

Eric
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Old   November 8, 2008, 01:39
Default It seems that the discretizati
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Prashant Ojha
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It seems that the discretization needs tuning, if you keep on getting the bounding error for k and epsilon the solution may blow up.

Just try tightening your tolerances.

Regards,
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Old   November 13, 2008, 14:34
Default Hello Foamers, i also have
  #25
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Oliver Sommer
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Hello Foamers,

i also have a problem with the buoyantFoam solver. I want to simulate a Cell with 1.1mmx10mm in x-y direction and 2D.

For testing i let the Fluid "air" in the "thermophysicalProperties"-File (simply copied the hotRoom example), but now i want to change to a liquid. Do i have to change the "thermoType"? Because i read in the Openfoam website something about liquids and so on. And in which combination can i use the keywords out from the UserGuide?

test case with "air":
hThermo<puremixture<consttransport<speciethermo<hc onstthermo<perfectgas>>>>>

The problem is, when i change the vaules for W, c_p, eta and Pr to the liquids (n_moles [1] and H_f [o] not changed) the velocities don't fit the experiment results. But is is of course different to the "air"-result.

Do i have to set the H_f value? Do i need it only when i want to "melt ice to water"?

thank you in advance

greets
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Old   November 14, 2008, 06:52
Default Hi, I'm considering a heate
  #26
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Pattyn Eric
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Hi,

I'm considering a heated channel flow.
On the plate, where the velocity is zero, the value of pd is different of zero while i thought pd was the dynamic pressure... Actually, i have a variation along x (direction of the flow) which makes me think to a rho g h quantity but i have set g=0 in the environnemental properties.

I have the similar problem with the p quantity of turbFoam, which is the kinematic pressure (User guide U-22). If p= rho V^2/2, for the same case but without heat, p should be 0 on the wall. However, i have the same value as pd for the heated case.

Could someone help me to understand what are these variables exactly?

Thank you

Eric
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