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A generalized thermal/dynamic wall function: Part 3

Posted October 17, 2016 at 11:25 by sbaffini (NuTBox)
Updated November 18, 2018 at 05:57 by sbaffini

In this post i summarize the initial problem and the procedure to determine the wall function value (i.e., the solution) for given

and

.

We looked for a solution $T^+\left(y^+,F_T^+,Pr,Pr_t\right)$ to the problem:

$\frac{dT^+}{dy^+}=\frac{Pr\left(1+F_T^+y^+\right)}{\left[1+\left(\frac{Pr}{Pr_t}\right)\left(\frac{\mu_t}{\mu}\right)\right]}$

with:

$\frac{\mu_t}{\mu}=\frac{\left(ky^+\right)^3}{\left(ky^+\right)^2+\left(ka_0\right)^3-\left(ka_0\right)^2}$ ...

Attached Files

wallfn.txt (2.2 KB, 534 views)

sbaffini

Senior Member

Posted in Basic Fluid Mechanics and CFD

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A generalized thermal/dynamic wall function: Part 2

Posted October 17, 2016 at 08:24 by sbaffini (NuTBox)
Updated April 28, 2022 at 07:50 by sbaffini

In the first part of this post we left with the problem of computing the following integral:

$f^+\left(y^+,\frac{Pr}{Pr_t}\right)=\int_0^{y+}{\frac{1}{\left[1+\left(\frac{Pr}{Pr_t}\right)\left(\frac{\mu_t}{\mu}\right)\right]}dz^+}$

with:

$\frac{\mu_t}{\mu}\left(y^+,a,k\right)=\frac{\left(ky^+\right)^3}{\left(ky^+\right)^2+\left(ka\right)^3-\left(ka\right)^2}$

I added all the explicit functional dependencies here because we know $f^+\left(y^+,1\right)$ ...

sbaffini

Senior Member

Posted in Basic Fluid Mechanics and CFD

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A generalized thermal/dynamic wall function: Part 1

Posted October 14, 2016 at 12:27 by sbaffini (NuTBox)
Updated December 21, 2016 at 09:07 by sbaffini

In a previous post i wrote about an extension of the Reichardt law of the wall to pressure gradient effects. That was derived by assuming the Reichardt profile as a solution for the case without pressure gradient and using integration by parts. In particular, given the the Reichardt function (

is the Von Karman constant):

$f^+\left(y^+\right) = \frac{1}{k}\log\left(1+ky^+\right) +A\left(1-e^{-\frac{y^+}{B}}-\frac{y^+}{B}e^{-\frac{y^+}{C}}\right)$

with:
...

sbaffini

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pimpleFoam vs simpleFoam vs pisoFoam vs icoFoam?

Posted October 14, 2016 at 11:27 by kindle
Updated October 24, 2016 at 11:37 by kindle

Quite confusing sometime !

But, why is that a problem needs boundary condition for U and p and all the other possible variables?

pisoFoam has relaxation coef while icoFoam does not have this.

Quote:

UEqn.relax();

Quote:

Originally Posted by ata

Hi
icoFoam is transient solver for incompressible, laminar flow of Newtonian fluids.

pimpleFoam is large time-step transient solver for incompressible, flow using the PIMPLE(merged PISO-SIMPLE) algorithm.

...

kindle

New Member

Posted in Solver

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Viscoelastic Fluid Flows using OpenFOAM The solver viscoelasticFluidFoam

Posted October 14, 2016 at 11:27 by kindle

This guy use Openfoam and FENE-P !!!

Quote:

Originally Posted by mmasoudian

Dear ata
I appreciate your quick answer

I compiled everything and I changed fvSolutions as you mentioned in forum but when I want to run a case (FENE-P): the error is:

mam@ubuntu:~/OpenFOAM/mam-2.0.0/RUN/tutorials/incompressible/viscoelasticFluidFoam/FENE-P$ viscoelasticFluidFoam
/*---------------------------------------------------------------------------*\
| ========= |

...

kindle

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Posted in Viscoelastic

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