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Commit 538dfcd6 authored by Andrew Heather's avatar Andrew Heather
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Merge branch 'feature-atmInletBCs' into 'develop' 

ENH: Improve and verify atmBoundaryLayerInlet conditions

See merge request !354
parents 5863c94b 336fb3bd
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src/atmosphericModels/Make/files
View file @ 538dfcd6
/* Models */
atmosphericTurbulentTransportModels.C
porosityModels/powerLawLopesdaCosta/powerLawLopesdaCosta.C
/* Boundary conditions */
derivedFvPatchFields/atmBoundaryLayer/atmBoundaryLayer.C
derivedFvPatchFields/atmBoundaryLayerInletVelocity/atmBoundaryLayerInletVelocityFvPatchVectorField.C
derivedFvPatchFields/atmBoundaryLayerInletK/atmBoundaryLayerInletKFvPatchScalarField.C
derivedFvPatchFields/atmBoundaryLayerInletEpsilon/atmBoundaryLayerInletEpsilonFvPatchScalarField.C
derivedFvPatchFields/atmBoundaryLayerInletOmega/atmBoundaryLayerInletOmegaFvPatchScalarField.C
derivedFvPatchFields/nutkAtmRoughWallFunction/nutkAtmRoughWallFunctionFvPatchScalarField.C
atmosphericTurbulentTransportModels.C
porosityModels/powerLawLopesdaCosta/powerLawLopesdaCosta.C
/* Wall function BCs */
/* fvOptions */
LIB = $(FOAM_LIBBIN)/libatmosphericModels
src/atmosphericModels/derivedFvPatchFields/atmBoundaryLayer/atmBoundaryLayer.C
View file @ 538dfcd6
......@@ -37,16 +37,20 @@ namespace Foam
atmBoundaryLayer::atmBoundaryLayer(const Time& time, const polyPatch& pp)
:
initABL_(false),
kappa_(0.41),
Cmu_(0.09),
C1_(0.0),
C2_(1.0),
ppMin_((boundBox(pp.points())).min()),
time_(time),
patch_(pp),
flowDir_(time, "flowDir"),
zDir_(time, "zDir"),
kappa_(0.41),
Cmu_(0.09),
Uref_(time, "Uref"),
Zref_(time, "Zref"),
z0_(),
zGround_()
d_()
{}
......@@ -57,6 +61,15 @@ atmBoundaryLayer::atmBoundaryLayer
const dictionary& dict
)
:
initABL_(dict.getOrDefault<Switch>("initABL", true)),
kappa_
(
dict.getCheckOrDefault<scalar>("kappa", 0.41, scalarMinMax::ge(SMALL))
),
Cmu_(dict.getCheckOrDefault<scalar>("Cmu", 0.09, scalarMinMax::ge(SMALL))),
C1_(dict.getOrDefault("C1", 0.0)),
C2_(dict.getOrDefault("C2", 1.0)),
ppMin_((boundBox(pp.points())).min()),
time_(time),
patch_(pp),
flowDir_(TimeFunction1<vector>(time, "flowDir", dict)),
......@@ -66,7 +79,7 @@ atmBoundaryLayer::atmBoundaryLayer
Uref_(TimeFunction1<scalar>(time, "Uref", dict)),
Zref_(TimeFunction1<scalar>(time, "Zref", dict)),
z0_(PatchFunction1<scalar>::New(pp, "z0", dict)),
zGround_(PatchFunction1<scalar>::New(pp, "zGround", dict))
d_(PatchFunction1<scalar>::New(pp, "d", dict))
{}
......@@ -77,31 +90,39 @@ atmBoundaryLayer::atmBoundaryLayer
const fvPatchFieldMapper& mapper
)
:
initABL_(abl.initABL_),
kappa_(abl.kappa_),
Cmu_(abl.Cmu_),
C1_(abl.C1_),
C2_(abl.C2_),
ppMin_(abl.ppMin_),
time_(abl.time_),
patch_(patch.patch()),
flowDir_(abl.flowDir_),
zDir_(abl.zDir_),
kappa_(abl.kappa_),
Cmu_(abl.Cmu_),
Uref_(abl.Uref_),
Zref_(abl.Zref_),
z0_(abl.z0_.clone(patch_)),
zGround_(abl.zGround_.clone(patch_))
d_(abl.d_.clone(patch_))
{}
atmBoundaryLayer::atmBoundaryLayer(const atmBoundaryLayer& abl)
:
initABL_(abl.initABL_),
kappa_(abl.kappa_),
Cmu_(abl.Cmu_),
C1_(abl.C1_),
C2_(abl.C2_),
ppMin_(abl.ppMin_),
time_(abl.time_),
patch_(abl.patch_),
flowDir_(abl.flowDir_),
zDir_(abl.zDir_),
kappa_(abl.kappa_),
Cmu_(abl.Cmu_),
Uref_(abl.Uref_),
Zref_(abl.Zref_),
z0_(abl.z0_.clone(patch_)),
zGround_(abl.zGround_.clone(patch_))
d_(abl.d_.clone(patch_))
{}
......@@ -110,13 +131,13 @@ atmBoundaryLayer::atmBoundaryLayer(const atmBoundaryLayer& abl)
vector atmBoundaryLayer::flowDir() const
{
const scalar t = time_.timeOutputValue();
vector dir(flowDir_.value(t));
const vector dir(flowDir_.value(t));
const scalar magDir = mag(dir);
if (magDir < SMALL)
{
FatalErrorInFunction
<< "magnitude of " << flowDir_.name()
<< "magnitude of " << flowDir_.name() << " = " << magDir
<< " vector must be greater than zero"
<< abort(FatalError);
}
......@@ -128,13 +149,13 @@ vector atmBoundaryLayer::flowDir() const
vector atmBoundaryLayer::zDir() const
{
const scalar t = time_.timeOutputValue();
vector dir(zDir_.value(t));
const vector dir(zDir_.value(t));
const scalar magDir = mag(dir);
if (magDir < SMALL)
{
FatalErrorInFunction
<< "magnitude of " << zDir_.name()
<< "magnitude of " << zDir_.name() << " = " << magDir
<< " vector must be greater than zero"
<< abort(FatalError);
}
......@@ -149,14 +170,22 @@ tmp<scalarField> atmBoundaryLayer::Ustar(const scalarField& z0) const
const scalar Uref = Uref_.value(t);
const scalar Zref = Zref_.value(t);
return kappa_*Uref/(log((Zref + z0)/z0));
if (Zref < 0)
{
FatalErrorInFunction
<< "Negative entry in " << Zref_.name() << " = " << Zref
<< abort(FatalError);
}
// (derived from RH:Eq. 6, HW:Eq. 5)
return kappa_*Uref/log((Zref + z0)/z0);
}
void atmBoundaryLayer::autoMap(const fvPatchFieldMapper& mapper)
{
z0_->autoMap(mapper);
zGround_->autoMap(mapper);
d_->autoMap(mapper);
}
......@@ -167,51 +196,80 @@ void atmBoundaryLayer::rmap
)
{
z0_->rmap(abl.z0_(), addr);
zGround_->rmap(abl.zGround_(), addr);
d_->rmap(abl.d_(), addr);
}
tmp<vectorField> atmBoundaryLayer::U(const vectorField& p) const
tmp<vectorField> atmBoundaryLayer::U(const vectorField& pCf) const
{
const scalar t = time_.timeOutputValue();
const scalarField zGround(zGround_->value(t));
const scalarField d(d_->value(t));
const scalarField z0(max(z0_->value(t), ROOTVSMALL));
const scalar groundMin = zDir() & ppMin_;
scalarField Un((Ustar(z0)/kappa_)*log(((zDir() & p) - zGround + z0)/z0));
// (YGCJ:Table 1, RH:Eq. 6, HW:Eq. 5)
scalarField Un
(
(Ustar(z0)/kappa_)*log(((zDir() & pCf) - groundMin - d + z0)/z0)
);
return flowDir()*Un;
}
tmp<scalarField> atmBoundaryLayer::k(const vectorField& p) const
tmp<scalarField> atmBoundaryLayer::k(const vectorField& pCf) const
{
const scalar t = time_.timeOutputValue();
const scalarField d(d_->value(t));
const scalarField z0(max(z0_->value(t), ROOTVSMALL));
const scalar groundMin = zDir() & ppMin_;
return sqr(Ustar(z0))/sqrt(Cmu_);
// (YGCJ:Eq. 21; RH:Eq. 7, HW:Eq. 6 when C1=0 and C2=1)
return
sqr(Ustar(z0))/sqrt(Cmu_)
*sqrt(C1_*log(((zDir() & pCf) - groundMin - d + z0)/z0) + C2_);
}
tmp<scalarField> atmBoundaryLayer::epsilon(const vectorField& p) const
tmp<scalarField> atmBoundaryLayer::epsilon(const vectorField& pCf) const
{
const scalar t = time_.timeOutputValue();
const scalarField zGround(zGround_->value(t));
const scalarField d(d_->value(t));
const scalarField z0(max(z0_->value(t), ROOTVSMALL));
const scalar groundMin = zDir() & ppMin_;
return pow3(Ustar(z0))/(kappa_*((zDir() & p) - zGround + z0));
// (YGCJ:Eq. 22; RH:Eq. 8, HW:Eq. 7 when C1=0 and C2=1)
return
pow3(Ustar(z0))/(kappa_*((zDir() & pCf) - groundMin - d + z0))
*sqrt(C1_*log(((zDir() & pCf) - groundMin - d + z0)/z0) + C2_);
}
tmp<scalarField> atmBoundaryLayer::omega(const vectorField& pCf) const
{
const scalar t = time_.timeOutputValue();
const scalarField d(d_->value(t));
const scalarField z0(max(z0_->value(t), ROOTVSMALL));
const scalar groundMin = zDir() & ppMin_;
// (YGJ:Eq. 13)
return Ustar(z0)/(kappa_*sqrt(Cmu_)*((zDir() & pCf) - groundMin - d + z0));
}
void atmBoundaryLayer::write(Ostream& os) const
{
z0_->writeData(os) ;
flowDir_.writeData(os);
zDir_.writeData(os);
os.writeEntry("initABL", initABL_);
os.writeEntry("kappa", kappa_);
os.writeEntry("Cmu", Cmu_);
os.writeEntry("C1", C1_);
os.writeEntry("C2", C2_);
flowDir_.writeData(os);
zDir_.writeData(os);
Uref_.writeData(os);
Zref_.writeData(os);
zGround_->writeData(os);
z0_->writeData(os) ;
d_->writeData(os);
}
......
src/atmosphericModels/derivedFvPatchFields/atmBoundaryLayer/atmBoundaryLayer.H
View file @ 538dfcd6
......@@ -6,7 +6,7 @@
\\/ M anipulation |
-------------------------------------------------------------------------------
Copyright (C) 2014-2018 OpenFOAM Foundation
Copyright (C) 2015 OpenCFD Ltd.
Copyright (C) 2015-2020 OpenCFD Ltd.
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
......@@ -31,84 +31,156 @@ Group
grpRASBoundaryConditions grpInletBoundaryConditions
Description
This class provides functions to evaluate the velocity and turbulence
distributions appropriate for atmospheric boundary layers (ABL).
Base class to set log-law type ground-normal inflow boundary conditions for
wind velocity and turbulence quantities for homogeneous, two-dimensional,
dry-air, equilibrium and neutral atmospheric boundary layer (ABL) modelling.
The profile is derived from the friction velocity, flow direction and
"vertical" direction:
The ground-normal profile expressions are due to \c YGCJ
(refer to references below) whereat \c RH expressions were generalised:
\f[
U = \frac{U^*}{\kappa} ln\left(\frac{z - z_g + z_0}{z_0}\right)
\f]
\f[
u = \frac{u^*}{\kappa} \ln \left( \frac{z - d + z_0}{z_0} \right)
\f]
\f[
k = \frac{(U^*)^2}{\sqrt{C_{\mu}}}
\f]
\f[
v = w = 0
\f]
\f[
\epsilon = \frac{(U^*)^3}{\kappa(z - z_g + z_0)}
\f]
\f[
k = \frac{(u^*)^2}{\sqrt{C_\mu}}
\sqrt{C_1 \ln \left( \frac{z - d + z_0}{z_0} \right) + C_2}
\f]
\f[
\epsilon = \frac{(u^*)^3}{\kappa (z - d + z_0)}
\sqrt{C_1 \ln \left( \frac{z - d + z_0}{z_0} \right) + C_2}
\f]
\f[
\omega = \frac{u^*}{\kappa \sqrt{C_\mu}} \frac{1}{z - d + z_0}
\f]
\f[
u^* =
\frac{u_{ref} \kappa}{\ln\left(\frac{z_{ref} + z_0}{z_0}\right)}
\f]
where
\vartable
U^* | Friction velocity
\kappa | von Karman's constant
C_{\mu} | Turbulence viscosity coefficient
z | Vertical coordinate
z_0 | Surface roughness height [m]
z_g | Minimum z-coordinate [m]
\endvartable
and
\f[
U^* = \kappa\frac{U_{ref}}{ln\left(\frac{Z_{ref} + z_0}{z_0}\right)}
\f]
where
\vartable
U_{ref} | Reference velocity at \f$Z_{ref}\f$ [m/s]
Z_{ref} | Reference height [m]
u | Ground-normal streamwise flow speed profile [m/s]
v | Spanwise flow speed [m/s]
w | Ground-normal flow speed [m/s]
k | Ground-normal turbulent kinetic energy (TKE) profile [m^2/s^2]
\epsilon | Ground-normal TKE dissipation rate profile [m^2/s^3]
\omega | Ground-normal specific dissipation rate profile [m^2/s^3]
u^* | Friction velocity [m/s]
\kappa | von Kármán constant [-]
C_\mu | Empirical model constant [-]
z | Ground-normal coordinate component [m]
d | Ground-normal displacement height [m]
z_0 | Aerodynamic roughness length [m]
u_{ref} | Reference mean streamwise wind speed at \f$z_{ref}\f$ [m/s]
z_{ref} | Reference height being used in \f$u^*\f$ estimations [m]
C_1 | Curve-fitting coefficient for \c YGCJ profiles [-]
C_2 | Curve-fitting coefficient for \c YGCJ profiles [-]
\endvartable
Use in the atmBoundaryLayerInletVelocity, atmBoundaryLayerInletK and
atmBoundaryLayerInletEpsilon boundary conditions.
Note
- The \c RH expressions are special cases of those in \c YGCJ when \c C1=0
and \c C2=1. Both \c C1 and \c C2 can be determined by nonlinear fitting
of (\c YGCJ:Eq. 19) with an experimental dataset for \c k. By default,
\c atmBoundaryLayerInlet boundary conditions compute \c RH expressions.
- \c z is the ground-normal height relative to the global minimum height
of the inlet patch; therefore, the minimum of \c z is always zero
irrespective of the absolute z-coordinate of the computational patch.
Reference:
D.M. Hargreaves and N.G. Wright, "On the use of the k-epsilon model
in commercial CFD software to model the neutral atmospheric boundary
layer", Journal of Wind Engineering and Industrial Aerodynamics
95(2007), pp 355-369.
\verbatim
The ground-normal profile expressions (tag:RH):
Richards, P. J., & Hoxey, R. P. (1993).
Appropriate boundary conditions for computational wind
engineering models using the k-ε turbulence model.
In Computational Wind Engineering 1 (pp. 145-153).
DOI:10.1016/B978-0-444-81688-7.50018-8
Modifications to preserve the profiles downstream (tag:HW):
Hargreaves, D. M., & Wright, N. G. (2007).
On the use of the k–ε model in commercial CFD software
to model the neutral atmospheric boundary layer.
Journal of wind engineering and
industrial aerodynamics, 95(5), 355-369.
DOI:10.1016/j.jweia.2006.08.002
Expression generalisations to allow height
variation for turbulence quantities (tag:YGCJ):
Yang, Y., Gu, M., Chen, S., & Jin, X. (2009).
New inflow boundary conditions for modelling the neutral equilibrium
atmospheric boundary layer in computational wind engineering.
J. of Wind Engineering and Industrial Aerodynamics, 97(2), 88-95.
DOI:10.1016/j.jweia.2008.12.001
The generalised ground-normal profile expression for omega (tag:YGJ):
Yang, Y., Gu, M., & Jin, X., (2009).
New inflow boundary conditions for modelling the
neutral equilibrium atmospheric boundary layer in SST k-ω model.
In: The Seventh Asia-Pacific Conference on Wind Engineering,
November 8-12, Taipei, Taiwan.
Theoretical remarks (tag:E):
Emeis, S. (2013).
Wind Energy Meteorology: Atmospheric
Physics for Wind Power Generation.
Springer-Verlag Berlin Heidelberg.
DOI:10.1007/978-3-642-30523-8
\endverbatim
Usage
\table
Property | Description | Required | Default
flowDir | Flow direction | yes |
zDir | Vertical direction | yes |
kappa | von Karman's constant | no | 0.41
Cmu | Turbulence viscosity coefficient | no | 0.09
Uref | Reference velocity [m/s] | yes |
Zref | Reference height [m] | yes |
z0 | Surface roughness height [m] | yes |
zGround | Minimum z-coordinate [m] | yes |
Property | Description | Type | Req'd | Deflt
flowDir | Flow direction | TimeFunction1<vector> | yes | -
zDir | Ground-normal direction | TimeFunction1<vector> | yes | -
Uref | Reference mean streamwise flow speed being used in <!--
--> \f$u^*\f$ estimations [m/s] | TimeFunction1<scalar> | yes | -
Zref | Reference height being used in \f$u^*\f$ estimations [m] <!--
--> | TimeFunction1<scalar> | yes | -
z0 | Surface roughness length [m] <!--
--> | PatchFunction1<scalar> | yes | -
d | Displacement height [m] - see Notes <!--
--> | PatchFunction1<scalar> | yes | -
kappa | von Kármán constant | scalar | no | 0.41
Cmu | Empirical model constant | scalar | no | 0.09
initABL | Flag to initialise profiles with the theoretical <!--
--> ABL expressions, otherwise use "value" list <!--
--> | bool | no | true
value | ABL profile content when initABL=false <!--
--> | scalarList | conditional | -
phi | Name of the flux field | word | no | phi
C1 | Curve-fitting coefficient \c YGCJ profiles | scalar | no | 0.0
C2 | Curve-fitting coefficient \c YGCJ profiles | scalar | no | 1.0
\endtable
Example of the boundary condition specification:
\verbatim
ground
{
type atmBoundaryLayerInletVelocity;
flowDir (1 0 0);
zDir (0 0 1);
Uref 10.0;
Zref 20.0;
z0 uniform 0.1;
zGround uniform 0.0;
}
\endverbatim
Note
D.M. Hargreaves and N.G. Wright recommend Gamma epsilon in the
k-epsilon model should be changed from 1.3 to 1.11 for consistency.
The roughness height (Er) is given by Er = 20 z0 following the same
reference.
- The derived ABL expressions automatically satisfy the simplified transport
equation for \c k. Yet the same expressions only satisfy the simplified
transport equation for \c epsilon when the model constants \c sigmaEpsilon
is 1.11 with \c kappa=0.4 (\c HW:p. 358).
- \c atmBoundaryLayerInlet boundary conditions inherit \c inletOutlet
traits, so that a given inlet condition can be supplied from all sides of
the domain, e.g. a ground-normal cylinder domain having a single
inlet/outlet boundary where the changes between inlet and outlet depend
on the wind direction and patch normals, so that any change in inflow
orientation can be handled with the same mesh.
- \c d is the displacement height, and "is relevant for flows over forests
and cities" (E:p. 28). "The displacement height gives the vertical
displacement of the entire flow regime over areas which are densely covered
with obstacles such as trees or buildings" (E:p. 28).
See also
- Foam::atmBoundaryLayer::atmBoundaryLayerInletVelocityFvPatchVectorField
- Foam::atmBoundaryLayer::atmBoundaryLayerInletKFvPatchScalarField
- Foam::atmBoundaryLayer::atmBoundaryLayerInletEpsilonFvPatchScalarField
- Foam::atmBoundaryLayer::atmBoundaryLayerInletOmegaFvPatchScalarField
- ExtendedCodeGuide::atmBoundaryLayer
SourceFiles
atmBoundaryLayer.C
......@@ -133,7 +205,33 @@ namespace Foam
class atmBoundaryLayer
{
// Private data
protected:
// Protected Data
//- Flag to initialise profiles with the theoretical ABL expressions,
//- otherwise initialises by using "value" entry content
Switch initABL_;
private:
// Private Data
//- von Kármán constant
const scalar kappa_;
//- Empirical model constant
const scalar Cmu_;
//- Curve-fitting coefficient
const scalar C1_;
//- Curve-fitting coefficient
const scalar C2_;
//- Minimum coordinate vector of this patch
const vector ppMin_;
//- Reference to the time database
const Time& time_;
......@@ -141,29 +239,23 @@ class atmBoundaryLayer
//- Reference to the patch
const polyPatch& patch_;
//- Flow direction
//- Streamwise flow direction
TimeFunction1<vector> flowDir_;
//- Direction of the z-coordinate
//- Direction of the ground-normal coordinate
TimeFunction1<vector> zDir_;
//- Von Karman constant
const scalar kappa_;
//- Turbulent viscosity coefficient
const scalar Cmu_;
//- Reference velocity
//- Reference mean streamwise flow speed being used in Ustar estimations
TimeFunction1<scalar> Uref_;
//- Reference height
//- Reference height being used in Ustar estimations
TimeFunction1<scalar> Zref_;
//- Surface roughness height
//- Surface roughness length
autoPtr<PatchFunction1<scalar>> z0_;
//- Minimum coordinate value in z direction
autoPtr<PatchFunction1<scalar>> zGround_;
//- Displacement height
autoPtr<PatchFunction1<scalar>> d_;
public:
......@@ -193,14 +285,14 @@ public:
atmBoundaryLayer(const atmBoundaryLayer&);
// Member functions
// Member Functions
// Access
//- Return flow direction
vector flowDir() const;
//- Return z-direction
//- Return the ground-normal direction
vector zDir() const;
//- Return friction velocity
......@@ -219,14 +311,16 @@ public:
// Evaluate functions
//- Return the velocity distribution for the ATM
tmp<vectorField> U(const vectorField& p) const;
tmp<vectorField> U(const vectorField& pCf) const;