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Bug: Coarsening+Viscosity #397

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Bug: Coarsening+Viscosity #397

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51282ec
fix the computation of velocity gradients in the viscosity module whe…
glesur Aug 12, 2026
103fc59
fix linter
glesur Aug 12, 2026
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174 changes: 126 additions & 48 deletions src/fluid/viscosity.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -111,9 +111,9 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
IdefixArray1D<real> x1l = this->data->xl[IDIR];
IdefixArray1D<real> x2l = this->data->xl[JDIR];
IdefixArray1D<real> x3l = this->data->xl[KDIR];
IdefixArray1D<real> dx1 = this->data->dx[IDIR];
IdefixArray1D<real> dx2 = this->data->dx[JDIR];
IdefixArray1D<real> dx3 = this->data->dx[KDIR];
IdefixArray1D<real> dx1Array = this->data->dx[IDIR];
IdefixArray1D<real> dx2Array = this->data->dx[JDIR];
IdefixArray1D<real> dx3Array = this->data->dx[KDIR];

// Fargo variables use to correct energy fluxes
#if HAVE_ENERGY
Expand All @@ -129,6 +129,14 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
IdefixArray1D<real> tanx2m = this->data->tanx2m;
#endif

// Coarsening parameters
bool haveGridCoarsening = data->haveGridCoarsening != GridCoarsening::disabled;
bool haveGridCoarseningX1 = data->coarseningDirection[IDIR];
bool haveGridCoarseningX2 = data->coarseningDirection[JDIR];
bool haveGridCoarseningX3 = data->coarseningDirection[KDIR];
auto coarseningLevelX1 = data->coarseningLevel[IDIR];
auto coarseningLevelX2 = data->coarseningLevel[JDIR];
auto coarseningLevelX3 = data->coarseningLevel[KDIR];

HydroModuleStatus haveViscosity = this->status.status;

Expand Down Expand Up @@ -201,18 +209,42 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
etaC2 = eta2 = eta2Constant;
}

EXPAND( dVxi = D_DX_I(Vc,VX1)/dx1(i); ,
dVyi = D_DX_I(Vc,VX2)/dx1(i); ,
dVzi = D_DX_I(Vc,VX3)/dx1(i); )
// Compute spacing
real dx1 = dx1Array(i);
real dx2 = dx2Array(j);
real dx3 = dx3Array(k);
Comment on lines +213 to +215

// Correct spacing for grid coarsening

if(haveGridCoarsening) {
if(haveGridCoarseningX1) {
const int factor = 1 << (coarseningLevelX1(k,j) - 1);
dx1 *= factor;
}

if(haveGridCoarseningX2) {
const int factor = 1 << (coarseningLevelX2(k,i) - 1);
dx2 *= factor;
}

if(haveGridCoarseningX3) {
const int factor = 1 << (coarseningLevelX3(j,i) - 1);
dx3 *= factor;
}
}

EXPAND( dVxi = D_DX_I(Vc,VX1)/dx1; ,
dVyi = D_DX_I(Vc,VX2)/dx1; ,
dVzi = D_DX_I(Vc,VX3)/dx1; )

#if DIMENSIONS >= 2
EXPAND( dVxj = D_DY_I(Vc,VX1)/dx2(j); ,
dVyj = D_DY_I(Vc,VX2)/dx2(j); ,
dVzj = D_DY_I(Vc,VX3)/dx2(j); )
EXPAND( dVxj = D_DY_I(Vc,VX1)/dx2; ,
dVyj = D_DY_I(Vc,VX2)/dx2; ,
dVzj = D_DY_I(Vc,VX3)/dx2; )
#if DIMENSIONS == 3
dVxk = D_DZ_I(Vc,VX1)/dx3(k);
dVyk = D_DZ_I(Vc,VX2)/dx3(k);
dVzk = D_DZ_I(Vc,VX3)/dx3(k);
dVxk = D_DZ_I(Vc,VX1)/dx3;
dVyk = D_DZ_I(Vc,VX2)/dx3;
dVzk = D_DZ_I(Vc,VX3)/dx3;
#endif
#endif

Expand All @@ -234,14 +266,14 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
tau_xy = eta1*(dVxj + dVyi);
SELECT( ,
,
tau_xz = eta1*0.5*(x1(i)+x1(i-1))/dx1(i)
tau_xz = eta1*0.5*(x1(i)+x1(i-1))/dx1
*(Vc(VX3,k,j,i)/x1(i) - Vc(VX3,k,j,i-1)/x1(i-1)); )

tau_xz = eta1*(dVxk + dVzi);

// compute tau_zz at cell center
divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1(i) + Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2(j) ,
divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1 + Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2 ,
);
tau_zz = 2.0*etaC1*Vc(VX1,k,j,i)/x1(i) + (etaC2 - (2.0/3.0)*etaC1)*divV;

Expand Down Expand Up @@ -269,14 +301,14 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>


// compute tau_yy at cell center
divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1(i) + Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2(j)/x1(i) ,
+0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3(k) );
divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1 + Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2/x1(i) ,
+0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3 );

#if DIMENSIONS == 1
tau_yy = 2.0*etaC1*( Vc(VX1,k,j,i)/x1(i)) + (etaC2 - (2.0/3.0)*etaC1)*divV;
#else
tau_yy = 2.0*etaC1*( 0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2(j)/x1(i)
tau_yy = 2.0*etaC1*( 0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2/x1(i)
+ Vc(VX1,k,j,i)/x1(i))
+ (etaC2 - (2.0/3.0)*etaC1)*divV;
#endif
Expand Down Expand Up @@ -325,14 +357,14 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>

// Compute tau_yy and tau_zz at cell center

divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1(i) + 2.0*Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2(j)/x1(i)
divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1 + 2.0*Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2/x1(i)
+Vc(VX2,k,j,i)/x1(i)*tan_1 ,
+0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3(k)/x1(i)*s_1 );
+0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3/x1(i)*s_1 );

tau_yy = Vc(VX1,k,j,i)/x1(i);
#if DIMENSIONS >= 2
tau_yy += 0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2(j)/x1(i);
tau_yy += 0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2/x1(i);
#endif
tau_yy = 2.0*etaC1*tau_yy + (etaC2-2.0/3.0*etaC1)*divV;

Expand All @@ -341,7 +373,7 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
tau_zz += Vc(VX2,k,j,i)*tan_1/x1(i);
#endif
#if DIMENSIONS == 3
tau_zz += 0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3(k)/x1(i)*s_1;
tau_zz += 0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3/x1(i)*s_1;
#endif
tau_zz = 2.0*etaC1*tau_zz + (etaC2-2.0/3.0*etaC1)*divV;

Expand Down Expand Up @@ -426,18 +458,41 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
etaC2 = eta2 = eta2Constant;
}

EXPAND( dVxi = D_DX_J(Vc,VX1)/dx1(i); ,
dVyi = D_DX_J(Vc,VX2)/dx1(i); ,
dVzi = D_DX_J(Vc,VX3)/dx1(i); )
// Compute spacing
real dx1 = dx1Array(i);
real dx2 = dx2Array(j);
real dx3 = dx3Array(k);

// Correct spacing for grid coarsening
if(haveGridCoarsening) {
if(haveGridCoarseningX1) {
const int factor = 1 << (coarseningLevelX1(k,j) - 1);
dx1 *= factor;
}

EXPAND( dVxj = D_DY_J(Vc,VX1)/dx2(j); ,
dVyj = D_DY_J(Vc,VX2)/dx2(j); ,
dVzj = D_DY_J(Vc,VX3)/dx2(j); )
if(haveGridCoarseningX2) {
const int factor = 1 << (coarseningLevelX2(k,i) - 1);
dx2 *= factor;
}

if(haveGridCoarseningX3) {
const int factor = 1 << (coarseningLevelX3(j,i) - 1);
dx3 *= factor;
}
}

EXPAND( dVxi = D_DX_J(Vc,VX1)/dx1; ,
dVyi = D_DX_J(Vc,VX2)/dx1; ,
dVzi = D_DX_J(Vc,VX3)/dx1; )

EXPAND( dVxj = D_DY_J(Vc,VX1)/dx2; ,
dVyj = D_DY_J(Vc,VX2)/dx2; ,
dVzj = D_DY_J(Vc,VX3)/dx2; )

#if DIMENSIONS == 3
dVxk = D_DZ_J(Vc,VX1)/dx3(k);
dVyk = D_DZ_J(Vc,VX2)/dx3(k);
dVzk = D_DZ_J(Vc,VX3)/dx3(k);
dVxk = D_DZ_J(Vc,VX1)/dx3;
dVyk = D_DZ_J(Vc,VX2)/dx3;
dVzk = D_DZ_J(Vc,VX3)/dx3;
#endif

#if GEOMETRY == CARTESIAN
Expand Down Expand Up @@ -508,8 +563,8 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
+ dVzk/x1(i)*s_1 );

// tau_xy is initially cell centered since it is involved in the source term
tau_xy = etaC1*( 0.5*(Vc(VX1,k,j+1,i)-Vc(VX1,k,j-1,i))/x1(i)/dx2(j)
+0.5*(Vc(VX2,k,j,i+1)-Vc(VX2,k,j,i-1))/dx1(i)
tau_xy = etaC1*( 0.5*(Vc(VX1,k,j+1,i)-Vc(VX1,k,j-1,i))/x1(i)/dx2
+0.5*(Vc(VX2,k,j,i+1)-Vc(VX2,k,j,i-1))/dx1
- Vc(VX2,k,j,i)/x1(i));
tau_yy = 2.0*eta1*(dVyj/x1(i) + vx1i/x1(i)) + (eta2 - (2.0/3.0)*eta1)*divV;

Expand Down Expand Up @@ -539,17 +594,17 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
s_1 = ONE_F/s_1;
}

divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1(i) + 2.0*Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2(j)/x1(i)
divV = D_EXPAND( 0.5*(Vc(VX1,k,j,i+1) - Vc(VX1,k,j,i-1))/dx1 + 2.0*Vc(VX1,k,j,i)/x1(i),
+0.5*(Vc(VX2,k,j+1,i) - Vc(VX2,k,j-1,i))/dx2/x1(i)
+Vc(VX2,k,j,i)/x1(i)*tan_1 ,
+0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3(k)/x1(i)*s_1 );
+0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3/x1(i)*s_1 );

tau_zz = Vc(VX1,k,j,i)/x1(i);
#if COMPONENTS >= 2
tau_zz += Vc(VX2,k,j,i)/x1(i)*tan_1;
#endif
#if DIMENSIONS == 3
tau_zz += 0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3(k)/x1(i)*s_1;
tau_zz += 0.5*(Vc(VX3,k+1,j,i) - Vc(VX3,k-1,j,i))/dx3/x1(i)*s_1;
#endif
tau_zz = 2*eta1*tau_zz + (eta2-2.0/3.0*eta1)*divV;

Expand Down Expand Up @@ -639,15 +694,38 @@ void Viscosity::AddViscousFlux(int dir, const real t, const IdefixArray4D<real>
etaC2 = eta2 = eta2Constant;
}

dVxi = D_DX_K(Vc,VX1)/dx1(i);
dVyi = D_DX_K(Vc,VX2)/dx1(i);
dVzi = D_DX_K(Vc,VX3)/dx1(i);
dVxj = D_DY_K(Vc,VX1)/dx2(j);
dVyj = D_DY_K(Vc,VX2)/dx2(j);
dVzj = D_DY_K(Vc,VX3)/dx2(j);
dVxk = D_DZ_K(Vc,VX1)/dx3(k);
dVyk = D_DZ_K(Vc,VX2)/dx3(k);
dVzk = D_DZ_K(Vc,VX3)/dx3(k);
// Compute spacing
real dx1 = dx1Array(i);
real dx2 = dx2Array(j);
real dx3 = dx3Array(k);

// Correct spacing for grid coarsening
if(haveGridCoarsening) {
if(haveGridCoarseningX1) {
const int factor = 1 << (coarseningLevelX1(k,j) - 1);
dx1 *= factor;
}

if(haveGridCoarseningX2) {
const int factor = 1 << (coarseningLevelX2(k,i) - 1);
dx2 *= factor;
}

if(haveGridCoarseningX3) {
const int factor = 1 << (coarseningLevelX3(j,i) - 1);
dx3 *= factor;
}
}

dVxi = D_DX_K(Vc,VX1)/dx1;
dVyi = D_DX_K(Vc,VX2)/dx1;
dVzi = D_DX_K(Vc,VX3)/dx1;
dVxj = D_DY_K(Vc,VX1)/dx2;
dVyj = D_DY_K(Vc,VX2)/dx2;
dVzj = D_DY_K(Vc,VX3)/dx2;
dVxk = D_DZ_K(Vc,VX1)/dx3;
dVyk = D_DZ_K(Vc,VX2)/dx3;
dVzk = D_DZ_K(Vc,VX3)/dx3;

#if GEOMETRY == CARTESIAN
divV = dVxi + dVyj + dVzk;
Expand Down
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