Code:
if (roughnessHeight_ > 0.0)
{
// Rough Walls
const scalar c_1 = 1/(90 - 2.25) + roughnessConstant_;
static const scalar c_2 = 2.25/(90 - 2.25);
static const scalar c_3 = 2.0*atan(1.0)/log(90/2.25);
static const scalar c_4 = c_3*log(2.25); //if (KsPlusBasedOnYPlus_)
{
// If KsPlus is based on YPlus the extra term added to the law
// of the wall will depend on yPlus
forAll(yPlus, facei)
{
const scalar Re = rho[facei]*magUp[facei]*y[facei]/muw[facei];
const scalar kappaRe = kappa_*Re;
scalar yp = yPlusLam_;
const scalar ryPlusLam = 1.0/yp;
int iter = 0;
scalar yPlusLast = 0.0;
scalar dKsPlusdYPlus = roughnessHeight_/y[facei];
// Enforce the roughnessHeight to be less than the distance to
// the first cell centre.
if (dKsPlusdYPlus > 1)
{
dKsPlusdYPlus = 1;
}
// Additional tuning parameter (fudge factor) - nominally = 1
dKsPlusdYPlus *= roughnessFactor_;
do
{
yPlusLast = yp;
// The non-dimensional roughness height
scalar KsPlus = yp*dKsPlusdYPlus;
// The extra term in the law-of-the-wall
scalar G = 0.0;
scalar yPlusGPrime = 0.0;
if (KsPlus >= 90)
{
const scalar t_1 = 1 + roughnessConstant_*KsPlus;
G = log(t_1);
yPlusGPrime = roughnessConstant_*KsPlus/t_1;
}
else if (KsPlus > 2.25)
{
const scalar t_1 = c_1*KsPlus - c_2;
const scalar t_2 = c_3*log(KsPlus) - c_4;
const scalar sint_2 = sin(t_2);
const scalar logt_1 = log(t_1);
G = logt_1*sint_2;
yPlusGPrime =
(c_1*sint_2*KsPlus/t_1) + (c_3*logt_1*cos(t_2));
}
scalar denom = 1.0 + log(E_*yp) - G - yPlusGPrime;
if (mag(denom) > VSMALL)
{
yp = (kappaRe + yp*(1 - yPlusGPrime))/denom;
}
} while
(
mag(ryPlusLam*(yp - yPlusLast)) > 0.0001
&& ++iter < 10
&& yp > VSMALL
);
yPlus[facei] = max(0.0, yp);
}
}
}
else
{
// Smooth Walls
forAll(yPlus, facei)
{
const scalar Re = rho[facei]*magUp[facei]*y[facei]/muw[facei];
const scalar kappaRe = kappa_*Re;
scalar yp = yPlusLam_;
const scalar ryPlusLam = 1.0/yp;
int iter = 0;
scalar yPlusLast = 0.0;
do
{
yPlusLast = yp;
yp = (kappaRe + yp)/(1.0 + log(E_*yp));
} while
(
mag(ryPlusLam*(yp - yPlusLast)) > 0.0001
&& ++iter < 10
);
yPlus[facei] = max(0.0, yp);
}
}