[jaswi]

Dear Developers

Sorry for posting this message here as there is no separate section for reporting such typos.

In the 2nd chapter on page U - 40 under the section 2.1.8.1 following is written:

Open the field files for and (0/k and 0/epsilon) and examine the boundary conditions. For a wall boundary condition, is assigned a zeroGradient boundary condition and a fixedValue 0 boundary condition is assigned to . How are the initial values of and arrived at? Positive, non-zero initial values for and must be given to avoid division by 0 in the solution algorithm.

As written here k is to be assigned fixedValue on the walls but this is not correct. The tutorial uses zeroGradient and also the wall functions used in High-Re turbulene models have in-built check to make sure that the boundary conditions on walls are zeroGradient.

Best Regards
jaswi

[Ahmed]

and a fixedValue 0 boundary condition is assigned to

Originally Posted by jaswi

Dear Developers

Sorry for posting this message here as there is no separate section for reporting such typos.

In the 2nd chapter on page U - 40 under the section 2.1.8.1 following is written:

As written here k is to be assigned fixedValue on the walls but this is not correct. The tutorial uses zeroGradient and also the wall functions used in High-Re turbulene models have in-built check to make sure that the boundary conditions on walls are zeroGradient.

Best Regards
jaswi

( and a fixedValue 0 boundary condition is assigned to ,) no slip boundary condition, velocity is zero at the wall hence k is 0

[jaswi]

Hi Ahmed

I did not understand your post. By k is 0, do you mean that k being set to fixedValue is correct ?

Please comment on this as after reading your post I tried to set k as fixedValue and value 0 but I get error that at wall k should be zerogradient. The message comes from this section of wallFunctionsI.H:


forAll(patches, patchi)
{
const fvPatch& curPatch = patches[patchi];

if (isType<wallFvPatch>(curPatch))
{
# include "checkPatchFieldTypes.H"
........
.........

where in checkPatchFieldTypes.H it is checked for the patch to be
zeroGradient else raise FatalError. This is what it reads:


if (!isType<zeroGradientFvPatchScalarField>(k_.bounda ryField()[patchi]))
00002 {
00003 FatalErrorIn("wall-function evaluation")
00004 << k_.boundaryField()[patchi].type()
00005 << " is the wrong k patchField type for wall-functions on patch "
00006 << curPatch.name() << nl
00007 << " should be zeroGradient"
00008 << exit(FatalError);
00009 }
00010
00011 if (!isType<zeroGradientFvPatchScalarField>(epsilon_. boundaryField()[patchi]))
00012 {
00013 FatalErrorIn("wall-function evaluation")
00014 << epsilon_.boundaryField()[patchi].type()
00015 << " is the wrong epsilon patchField type for wall-functions on patch "
00016 << curPatch.name() << nl
00017 << " should be zeroGradient"
00018 << exit(FatalError);
00019 }



Any comments are appreciated

BR
jaswi