olb::entropicLbHelpers< T, descriptors::D3Q19<> > Struct Template Reference

#include <entropicLbHelpers3D.h>

Collaboration diagram for olb::entropicLbHelpers< T, descriptors::D3Q19<> >:

Static Public Member Functions
static T	equilibrium (int iPop, T rho, const T u[3])
	Computation of equilibrium distribution with an expansion with respect to a small velocity u.

Detailed Description

template<typename T>
struct olb::entropicLbHelpers< T, descriptors::D3Q19<> >

Definition at line 36 of file entropicLbHelpers3D.h.

Member Function Documentation

equilibrium()

template<typename T >

static T olb::entropicLbHelpers< T, descriptors::D3Q19<> >::equilibrium ( int iPop, T rho, const T u[3] )

inlinestatic

Computation of equilibrium distribution with an expansion with respect to a small velocity u.

Definition at line 39 of file entropicLbHelpers3D.h.

  {
    typedef descriptors::D3Q19<> L;
 
    T c_u = descriptors::c<L>(iPop,0)*u[0] + descriptors::c<L>(iPop,1)*u[1] + descriptors::c<L>(iPop,2)*u[2];;
    T c_u2 = c_u*c_u;
    T c_u3 = c_u2*c_u;
    T c_u4 = c_u3*c_u;
    T c_u5 = c_u4*c_u;
    T c_u6 = c_u5*c_u;
    T c_u7 = c_u6*c_u;
 
    T uSqr = u[0]*u[0] + u[1]*u[1] + u[2]*u[2];
    T uSqr2 = uSqr*uSqr;
    T uSqr3 = uSqr2*uSqr;
 
    T powUx = u[0]*u[0]*u[0]*u[0]*u[0]; // u_x^5
    T powUy = u[1]*u[1]*u[1]*u[1]*u[1]; // u_y^5
    T powUz = u[2]*u[2]*u[2]*u[2]*u[2]; // u_z^5
 
    T C = descriptors::c<L>(iPop,0) * powUx + descriptors::c<L>(iPop,1) * powUy
          + descriptors::c<L>(iPop,2) * powUz;
 
    powUx *= u[0]; // u_x^6
    powUy *= u[1]; // u_y^6
    powUz *= u[2]; // u_z^6
 
    T E = powUx + powUy + powUz;
 
    powUx *= u[0]; // u_x^7
    powUy *= u[1]; // u_y^7
    powUz *= u[2]; // u_z^7
 
    T F = descriptors::c<L>(iPop,0) * powUx + descriptors::c<L>(iPop,1) * powUy + descriptors::c<L>(iPop,2) * powUz;
 
    return descriptors::t<T,L>(iPop) * rho *
           ((T)1
            + c_u*(C*(T)81/(T)20 + uSqr2*(T)27/(T)8 - uSqr*(T)9/(T)2
                   - E*(T)81/(T)24 - uSqr3*(T)81/(T)48 + (T)3)
 
            + c_u2*(uSqr2*(T)81/(T)16 - uSqr*(T)27/(T)4
                    + C*(T)243/(T)40 + (T)9/(T)2)
 
            + c_u3*(uSqr2*(T)243/(T)48 - uSqr*(T)81/(T)12 + (T)27/(T)6)
 
            - c_u4*uSqr*(T)243/(T)48
            + c_u4*(T)81/(T)24
 
            - c_u5*uSqr*(T)729/(T)240
            + c_u5*(T)243/(T)120
 
            + c_u6*(T)729/(T)720
 
            + c_u7*(T)2187/(T)5040
 
            - C*uSqr*(T)81/(T)40
 
            + C*(T)27/(T)20 - uSqr3*(T)27/(T)48 - E*(T)27/(T)24
            - F*(T)81/(T)56 - uSqr*(T)3/(T)2 + uSqr2*(T)9/(T)8
           )
           - descriptors::t<T,L>(iPop);
  }

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The documentation for this struct was generated from the following file:

• src/dynamics/entropicLbHelpers3D.h