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/* This file is part of the OpenLB library
*
* Copyright (C) 2017-2018 Max Gaedtke, Albert Mink, Davide Dapelo
* E-mail contact: info@openlb.net
* The most recent release of OpenLB can be downloaded at
* <http://www.openlb.net/>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/** \file
* Unit conversion handling -- header file.
*/
#ifndef PL_UNITCONVERTER_H
#define PL_UNITCONVERTER_H
#include <math.h>
#include "io/ostreamManager.h"
#include "core/util.h"
#include "io/xmlReader.h"
#include "unitConverter.h"
/// All OpenLB code is contained in this namespace.
namespace olb {
/** Conversion between physical and lattice units, as well as discretization specialized for power-law rheology: \f$\nu=m^{n-1}\f$, with \f$m$ being the consistency coefficient and \f$n\f$ the power-law index.
* The Newtonian case is recovered for \f$n=1\f$.
* A characteristic (apparent) kinematic viscosity for problem similarity (e.g., to compute the Reynolds number) is obtained as __physViscosity = poweLawConsistencyCoeff * [physVelocity / (2*physLength)]^(n-1)__.
* Be aware of the nomenclature:
* We distingish between physical (dimensioned) and lattice (dimensionless) values.
* A specific conversion factor maps the two different scopes,
* e.g. __physLength = conversionLength * latticeLength__
*
* For pressure and temperature we first shift the physical values by a characteristic value to asure a lattice pressure and lattice temperature between 0 and 1, e.g. __physPressure - charPhysPressure = conversionPressure * latticePressure__
*
* \param latticeRelaxationTime relaxation time, have to be greater than 0.5!
* - - -
* \param physViscosity physical kinematic viscosity in __m^2 / s__
* \param poweLawIndex power-law index
* \param physConsistencyCoeff physicsl consistency coefficient __m^2 s^(n-2)__
* \param physDensity physical density in __kg / m^3__
* - - -
* \param conversionLength conversion factor for length __m__
* \param conversionTime conversion factor for time __s__
* \param conversionMass conversion factor for mass __kg__
* - - -
* \param conversionVelocity conversion velocity __m / s__
* \param conversionViscosity conversion kinematic viscosity __m^2 / s__
* \param conversionConsistencyCoeff conversion power-law consistency coefficient __m^2 s^(n-2)__
* \param conversionDensity conversion density __kg / m^3__
* \param conversionForce conversion force __kg m / s^2__
* \param conversionPressure conversion pressure __kg / m s^2__
* - - -
* \param resolution number of grid points per charPhysLength
* - - -
* \param charLatticeVelocity
*/
template <typename T, typename DESCRIPTOR>
class PowerLawUnitConverter : public UnitConverter<T, DESCRIPTOR> {
public:
/** Documentation of constructor:
* \param physDeltaX spacing between two lattice cells in __m__
* \param physDeltaT time step in __s__
* \param charPhysLength reference/characteristic length of simulation geometry in __m__
* \param charPhysVelocity maximal or highest expected velocity during simulation in __m / s__
* \param physConsistencyCoeff physical power-law consistency coefficient in __m^2 s^(n-2)__
* \param powerLawIndex Power-law index
* \param physDensity physical density in __kg / m^3__
* \param charPhysPressure reference/characteristic physical pressure in Pa = kg / m s^2
*/
constexpr PowerLawUnitConverter( T physDeltaX, T physDeltaT, T charPhysLength,
T charPhysVelocity, T physConsistencyCoeff, T powerLawIndex,
T physDensity, T charPhysPressure = 0 )
: UnitConverter<T, DESCRIPTOR>( physDeltaX, physDeltaT, charPhysLength, charPhysVelocity,
physConsistencyCoeff * pow(charPhysVelocity / (2*charPhysLength), powerLawIndex-1),
physDensity, charPhysPressure ),
_conversionConsistencyCoeff(pow( physDeltaT,powerLawIndex-2 ) * pow( physDeltaX,2 ) ),
_powerLawIndex(powerLawIndex),
_physConsistencyCoeff(physConsistencyCoeff),
clout(std::cout,"PowerLawUnitConverter")
{
}
/// return consistency coefficient in physical units
constexpr T getPhysConsistencyCoeff( ) const
{
return _physConsistencyCoeff;
}
/// conversion from lattice to physical consistency coefficient
constexpr T getPhysConsistencyCoeff( T latticeConsistencyCoeff ) const
{
return _conversionConsistencyCoeff * latticeConsistencyCoeff;
}
/// conversion from physical to lattice consistency coefficient
constexpr T getLatticeConsistencyCoeff( ) const
{
return _physConsistencyCoeff / _conversionConsistencyCoeff;
}
/// access (read-only) to private member variable
constexpr T getConversionFactorConsistencyCoeff() const
{
return _conversionConsistencyCoeff;
}
/// access (read-only) to private member variable
constexpr T getPowerLawIndex() const
{
return _powerLawIndex;
}
/// nice terminal output for conversion factors, characteristical and physical data
virtual void print() const;
void write(std::string const& fileName = "unitConverter") const;
protected:
// conversion factors
const T _conversionConsistencyCoeff; // m^2 s^(n-2)
// physical units, e.g characteristic or reference values
const T _powerLawIndex;
const T _physConsistencyCoeff; // m^2 s^(n-2)
private:
mutable OstreamManager clout;
};
/// creator function with data given by a XML file
template <typename T, typename DESCRIPTOR>
PowerLawUnitConverter<T, DESCRIPTOR>* createPowerLawUnitConverter(XMLreader const& params);
template <typename T, typename DESCRIPTOR>
class PowerLawUnitConverterFrom_Resolution_RelaxationTime_Reynolds_PLindex : public PowerLawUnitConverter<T, DESCRIPTOR> {
public:
constexpr PowerLawUnitConverterFrom_Resolution_RelaxationTime_Reynolds_PLindex(
int resolution,
T latticeRelaxationTime,
T charPhysLength,
T charPhysVelocity,
T Re,
T powerLawIndex,
T physDensity,
T charPhysPressure = 0)
: PowerLawUnitConverter<T, DESCRIPTOR>( (charPhysLength/resolution),
(latticeRelaxationTime - 0.5) / descriptors::invCs2<T,DESCRIPTOR>() * pow((charPhysLength/resolution),2) / ( ( charPhysLength * charPhysVelocity * pow( charPhysVelocity / ( 2 * charPhysLength ), 1 - powerLawIndex ) / Re ) * pow( charPhysVelocity / (2 * charPhysLength ), powerLawIndex - 1 ) ),
charPhysLength, charPhysVelocity,
charPhysLength * charPhysVelocity * pow( charPhysVelocity / ( 2 * charPhysLength ), 1 - powerLawIndex ) / Re, powerLawIndex, physDensity, charPhysPressure )
{
}
};
} // namespace olb
#endif
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