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lammps/lib/atc/ViscousStress.h
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ViscousStress.h
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#ifndef VISCOUS_STRESS_H
#define VISCOUS_STRESS_H
#include <map>
#include <string>
#include <vector>
#include <fstream>
#include "MatrixLibrary.h"
#include "ATC_TypeDefs.h"
namespace ATC {
/**
* @class ViscousStress
* @brief Base class that defines interface for a constitutive law
* @brief that computes viscous stresses given all field and gradient information.
*/
class ViscousStress
{
public:
ViscousStress() {};
virtual ~ViscousStress() {};
virtual void initialize(void){};
//* Returns parameter values, (Nothing uses this).
virtual void parameters(std::map<std::string,double> &parameters) {}
//* Computes viscous stress given a strain rate tensor.
//* Units: mvv/L^3 (i.e. for units Real: g/(mol ps^2 A^2) )
virtual void viscous_stress(const FIELD_MATS &fields,
const GRAD_FIELD_MATS &gradFields,
DENS_MAT_VEC &stress)=0;
virtual void viscosity(const FIELD_MATS & fields,
DENS_MAT & coefs) const
{throw ATC_Error("ViscousStress::viscosity: unimplemented function");}
//* Returns the derivative of the stress tensor for a given strain-rate tensor.
virtual void tangent(const MATRIX &F, MATRIX &C) const
{throw ATC_Error("ViscousStress::tangent: unimplemented function");}
};
/**
* @class ViscousStressConstant
* @brief Class for computing stress for a constant viscosity material
* assuming divergence-free flow
*/
class ViscousStressConstant : public ViscousStress
{
public:
ViscousStressConstant():viscosity_(0.){};
ViscousStressConstant(std::fstream &matfile);
ViscousStressConstant(double viscosity)
: viscosity_(viscosity) {};
void viscous_stress(const FIELD_MATS &fields,
const GRAD_FIELD_MATS &gradFields,
DENS_MAT_VEC &flux);
void viscosity(const FIELD_MATS & fields,
DENS_MAT & coefs) const;
protected:
double viscosity_;
void set_tangent();
};
}
#endif
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