#include <generalised_newtonian_constitutive_models.h>

Inheritance diagram for oomph::PowerLawBerEngRegConstitutiveEquation< DIM >:

Public Member Functions
	PowerLawBerEngRegConstitutiveEquation (double power_pt, double reg_par_pt)

double	viscosity (const double &second_invariant_of_rate_of_strain_tensor)

Public Member Functions inherited from oomph::GeneralisedNewtonianConstitutiveEquation< DIM >
	GeneralisedNewtonianConstitutiveEquation ()
	Empty constructor. More...

virtual	~GeneralisedNewtonianConstitutiveEquation ()
	Empty virtual destructor. More...

virtual double	dviscosity_dinvariant (const double &second_invariant_of_rate_of_strain_tensor)=0

Private Attributes
double *	Power_pt
	power law index n More...

double *	Regularisation_parameter_pt
	regularisation parameter e << 1 More...

Detailed Description

template<unsigned DIM>
class oomph::PowerLawBerEngRegConstitutiveEquation< DIM >

A GeneralisedNewtonianConstitutiveEquation class defining a power-law fluid regularised according to Bercovier and Engelman (1980) to allow for n < 1

Constructor & Destructor Documentation

◆ PowerLawBerEngRegConstitutiveEquation()

template<unsigned DIM>

oomph::PowerLawBerEngRegConstitutiveEquation< DIM >::PowerLawBerEngRegConstitutiveEquation	(	double *	power_pt,
		double *	reg_par_pt
	)

inline

       : GeneralisedNewtonianConstitutiveEquation<DIM>(),
         Power_pt(power_pt),
         Regularisation_parameter_pt(reg_par_pt)
     {
     }

Member Function Documentation

◆ viscosity()

template<unsigned DIM>

double oomph::PowerLawBerEngRegConstitutiveEquation< DIM >::viscosity ( const double & second_invariant_of_rate_of_strain_tensor )

inlinevirtual

Function implementing the constitutive model Input: second invariant of the rate of strain Output: the viscosity For Newtonian behaviour this returns 1

Implements oomph::GeneralisedNewtonianConstitutiveEquation< DIM >.

     {
       // Pre-multiply the second invariant with +/-1 depending on whether it's
       // positive or not
       double sign = -1.0;
       if (second_invariant_of_rate_of_strain_tensor >= 0.0)
       {
         sign = 1.0;
       }
  
       // Calculate the square root of the absolute value of the
       // second invariant of the rate of strain tensor
       double measure_of_rate_of_strain =
         sqrt(sign * second_invariant_of_rate_of_strain_tensor);
  
       return pow(
         (2.0 * measure_of_rate_of_strain + *Regularisation_parameter_pt),
         *Power_pt - 1.0);
     }