struct BlockedThermalParameters
: public boost::enable_shared_from_this<BlockedThermalParameters> {
}
return boost::shared_ptr<double>(shared_from_this(),
}
return boost::shared_ptr<double>(shared_from_this(), &
heatCapacity);
}
}
};
boost::ptr_deque<ForcesAndSourcesCore::UserDataOperator> &pipeline,
std::string block_name,
boost::shared_ptr<BlockedThermalParameters> blockedParamsPtr,
double default_thermal_capacity_scale, Sev sev,
double local_heat_capacity_scale = default_thermal_capacity_scale;
OpMatThermalBlocks(boost::shared_ptr<double> conductivity_ptr,
boost::shared_ptr<double> capacity_ptr,
boost::shared_ptr<double> heat_conductivity_scaling_ptr,
boost::shared_ptr<double> heat_capacity_scaling_ptr,
double local_heat_conductivity,
double local_heat_capacity,
double local_heat_conductivity_scale,
double local_heat_capacity_scale,
std::vector<const CubitMeshSets *> meshset_vec_ptr)
conductivityPtr(conductivity_ptr), capacityPtr(capacity_ptr),
conductivityScalingPtr(heat_conductivity_scaling_ptr),
capacityScalingPtr(heat_capacity_scaling_ptr),
defaultHeatConductivity(local_heat_conductivity),
defaultHeatCapacity(local_heat_capacity),
defaultHeatConductivityScale(local_heat_conductivity_scale),
defaultHeatCapacityScale(local_heat_capacity_scale),
"Cannot get data from thermal block");
}
MoFEMErrorCode doWork(int side, EntityType type,
EntitiesFieldData::EntData &data) {
auto scale_param = [this](auto parameter, double scaling) {
return parameter * scaling;
};
for (auto &b : blockData) {
if (b.blockEnts.find(getFEEntityHandle()) != b.blockEnts.end()) {
*conductivityScalingPtr =
thermalConductivityScaling(b.conductivity, b.capacity);
*conductivityPtr =
scale_param(b.conductivity, *conductivityScalingPtr);
*capacityScalingPtr = heatCapacityScaling(b.conductivity, b.capacity);
*capacityPtr = scale_param(b.capacity, *capacityScalingPtr);
}
}
*conductivityScalingPtr = thermalConductivityScaling(
defaultHeatConductivity / defaultHeatConductivityScale,
defaultHeatCapacity /
defaultHeatCapacityScale);
*conductivityPtr =
scale_param(defaultHeatConductivity, *conductivityScalingPtr);
*capacityScalingPtr = heatCapacityScaling(
defaultHeatConductivity / defaultHeatConductivityScale,
defaultHeatCapacity /
defaultHeatCapacityScale);
*capacityPtr = scale_param(defaultHeatCapacity, *capacityScalingPtr);
}
private:
double defaultHeatConductivity;
double defaultHeatCapacity;
double defaultHeatConductivityScale;
double defaultHeatCapacityScale;
double conductivity;
double capacity;
};
std::vector<BlockData> blockData;
MoFEMErrorCode
std::vector<const CubitMeshSets *> meshset_vec_ptr,
Sev sev) {
for (
auto m : meshset_vec_ptr) {
std::vector<double> block_data;
CHKERR m->getAttributes(block_data);
if (block_data.size() < 2) {
"Expected that block has at least two attributes");
}
auto get_block_ents = [&]() {
m_field.
get_moab().get_entities_by_handle(
m->meshset, ents,
true);
return ents;
};
<<
m->getName() <<
": conductivity = " << block_data[0]
<< " capacity = " << block_data[1];
blockData.push_back({block_data[0], block_data[1], get_block_ents()});
}
}
boost::shared_ptr<double> conductivityPtr;
boost::shared_ptr<double> conductivityScalingPtr;
boost::shared_ptr<double> capacityPtr;
boost::shared_ptr<double> capacityScalingPtr;
};
pipeline.push_back(new OpMatThermalBlocks(
blockedParamsPtr->getHeatConductivityPtr(),
blockedParamsPtr->getHeatCapacityPtr(),
blockedParamsPtr->getHeatConductivityScalingPtr(),
blockedParamsPtr->getHeatCapacityScalingPtr(), local_heat_conductivity,
local_heat_capacity, local_heat_conductivity_scale,
local_heat_capacity_scale, thermal_conductivity_scaling_func,
heat_capacity_scaling_func, m_field, sev,
m_field.
getInterface<MeshsetsManager>()->getCubitMeshsetPtr(std::regex(
(boost::format("%s(.*)") % block_name).str()
))
));
}
struct BlockedThermoElasticParameters
: public boost::enable_shared_from_this<BlockedThermoElasticParameters> {
return boost::shared_ptr<VectorDouble>(shared_from_this(), &
coeffExpansion);
}
return boost::shared_ptr<double>(shared_from_this(), &
refTemp);
}
};
boost::ptr_deque<ForcesAndSourcesCore::UserDataOperator> &pipeline,
std::string block_name,
boost::shared_ptr<BlockedThermoElasticParameters> blockedParamsPtr,
OpMatThermoElasticBlocks(boost::shared_ptr<VectorDouble> expansion_ptr,
boost::shared_ptr<double> ref_temp_ptr,
double local_coeff_expansion,
Sev sev,
std::vector<const CubitMeshSets *> meshset_vec_ptr)
expansionPtr(expansion_ptr), refTempPtr(ref_temp_ptr),
defaultCoeffExpansion(local_coeff_expansion),
defaultRefTemp(local_ref_temp) {
extractThermoElasticBlockData(m_field, meshset_vec_ptr, sev),
"Cannot get data from thermoelastic block");
}
MoFEMErrorCode doWork(int side, EntityType type,
EntitiesFieldData::EntData &data) {
for (auto &b : blockData) {
if (b.blockEnts.find(getFEEntityHandle()) != b.blockEnts.end()) {
*expansionPtr = b.expansion;
*refTempPtr = b.ref_temp;
}
}
*expansionPtr = VectorDouble(
SPACE_DIM, defaultCoeffExpansion);
*refTempPtr = defaultRefTemp;
}
private:
double defaultCoeffExpansion;
double defaultRefTemp;
double ref_temp;
VectorDouble expansion;
};
std::vector<BlockData> blockData;
MoFEMErrorCode extractThermoElasticBlockData(
std::vector<const CubitMeshSets *> meshset_vec_ptr, Sev sev) {
for (
auto m : meshset_vec_ptr) {
std::vector<double> block_data;
CHKERR m->getAttributes(block_data);
if (block_data.size() < 2) {
"Expected that block has at least two attributes");
}
auto get_block_ents = [&]() {
m_field.
get_moab().get_entities_by_handle(
m->meshset, ents,
true);
return ents;
};
auto get_expansion = [&]() {
VectorDouble expansion(
SPACE_DIM, block_data[1]);
if (block_data.size() > 2) {
expansion[1] = block_data[2];
}
if (
SPACE_DIM == 3 && block_data.size() > 3) {
expansion[2] = block_data[3];
}
return expansion;
};
auto coeff_exp_vec = get_expansion();
<< " ref_temp = " << block_data[0]
<< " expansion = " << coeff_exp_vec;
blockData.push_back({block_data[0], coeff_exp_vec, get_block_ents()});
}
}
boost::shared_ptr<VectorDouble> expansionPtr;
boost::shared_ptr<double> refTempPtr;
};
pipeline.push_back(new OpMatThermoElasticBlocks(
blockedParamsPtr->getCoeffExpansionPtr(),
blockedParamsPtr->getRefTempPtr(), local_coeff_expansion, local_ref_temp,
m_field, sev,
m_field.
getInterface<MeshsetsManager>()->getCubitMeshsetPtr(std::regex(
(boost::format("%s(.*)") % block_name).str()
))
));
}
OpKCauchyThermoElasticity(
const std::string row_field_name, const std::string col_field_name,
boost::shared_ptr<MatrixDouble> mDptr,
boost::shared_ptr<VectorDouble> coeff_expansion_ptr);
MoFEMErrorCode
iNtegrate(EntitiesFieldData::EntData &row_data,
EntitiesFieldData::EntData &col_data);
private:
boost::shared_ptr<MatrixDouble>
mDPtr;
};
boost::shared_ptr<MatrixDouble> strain_ptr,
boost::shared_ptr<VectorDouble> temp_ptr,
boost::shared_ptr<MatrixDouble> m_D_ptr,
boost::shared_ptr<VectorDouble> coeff_expansion_ptr,
boost::shared_ptr<MatrixDouble> stress_ptr);
OpStressThermal(boost::shared_ptr<MatrixDouble> strain_ptr,
boost::shared_ptr<VectorDouble> temp_ptr,
boost::shared_ptr<MatrixDouble> m_D_ptr,
boost::shared_ptr<VectorDouble> coeff_expansion_ptr,
boost::shared_ptr<double> ref_temp_ptr,
boost::shared_ptr<MatrixDouble> stress_ptr);
private:
boost::shared_ptr<VectorDouble>
tempPtr;
boost::shared_ptr<MatrixDouble>
mDPtr;
};
const std::string row_field_name, const std::string col_field_name,
boost::shared_ptr<MatrixDouble> mDptr,
boost::shared_ptr<VectorDouble> coeff_expansion_ptr)
DomainEleOp::OPROWCOL),
mDPtr(mDptr), coeffExpansionPtr(coeff_expansion_ptr) {
sYmm = false;
}
MoFEMErrorCode
EntitiesFieldData::EntData &col_data) {
auto &locMat = AssemblyDomainEleOp::locMat;
const auto nb_integration_pts = row_data.getN().size1();
const auto nb_row_base_functions = row_data.getN().size2();
auto t_w = getFTensor0IntegrationWeight();
auto t_row_diff_base = row_data.getFTensor1DiffN<
SPACE_DIM>();
auto t_D = getFTensor4DdgFromMat<SPACE_DIM, SPACE_DIM, 0>(*
mDPtr);
t_coeff_exp(d, d) = (*coeffExpansionPtr)[d];
}
t_eigen_strain(
i,
j) = (t_D(
i,
j,
k,
l) * t_coeff_exp(
k,
l));
for (auto gg = 0; gg != nb_integration_pts; ++gg) {
double alpha = getMeasure() * t_w;
auto rr = 0;
for (; rr != AssemblyDomainEleOp::nbRows /
SPACE_DIM; ++rr) {
auto t_mat = getFTensor1FromMat<SPACE_DIM, 1>(locMat, rr *
SPACE_DIM);
auto t_col_base = col_data.getFTensor0N(gg, 0);
for (auto cc = 0; cc != AssemblyDomainEleOp::nbCols; cc++) {
(t_row_diff_base(
j) * t_eigen_strain(
i,
j)) * (t_col_base * alpha);
++t_mat;
++t_col_base;
}
++t_row_diff_base;
}
for (; rr != nb_row_base_functions; ++rr)
++t_row_diff_base;
++t_w;
}
}
const std::string
field_name, boost::shared_ptr<MatrixDouble> strain_ptr,
boost::shared_ptr<VectorDouble> temp_ptr,
boost::shared_ptr<MatrixDouble> m_D_ptr,
boost::shared_ptr<VectorDouble> coeff_expansion_ptr,
boost::shared_ptr<MatrixDouble> stress_ptr)
tempPtr(temp_ptr), mDPtr(m_D_ptr), coeffExpansionPtr(coeff_expansion_ptr),
stressPtr(stress_ptr) {
std::fill(&doEntities[MBEDGE], &doEntities[MBMAXTYPE], false);
}
boost::shared_ptr<MatrixDouble> strain_ptr,
boost::shared_ptr<VectorDouble> temp_ptr,
boost::shared_ptr<MatrixDouble> m_D_ptr,
boost::shared_ptr<VectorDouble> coeff_expansion_ptr,
boost::shared_ptr<double> ref_temp_ptr,
boost::shared_ptr<MatrixDouble> stress_ptr)
tempPtr(temp_ptr), mDPtr(m_D_ptr), coeffExpansionPtr(coeff_expansion_ptr),
refTempPtr(ref_temp_ptr), stressPtr(stress_ptr) {}
const auto nb_gauss_pts = getGaussPts().size2();
auto t_D = getFTensor4DdgFromMat<SPACE_DIM, SPACE_DIM, 0>(*
mDPtr);
auto t_strain = getFTensor2SymmetricFromMat<SPACE_DIM>(*
strainPtr);
auto t_stress = getFTensor2SymmetricFromMat<SPACE_DIM>(*
stressPtr);
auto t_temp = getFTensor0FromVec(*
tempPtr);
t_coeff_exp(d, d) = (*coeffExpansionPtr)[d];
}
for (size_t gg = 0; gg != nb_gauss_pts; ++gg) {
(t_strain(
k,
l) - t_coeff_exp(
k,
l) * (t_temp - (*refTempPtr)));
++t_strain;
++t_stress;
++t_temp;
}
}
struct SetTargetTemperature;
}
template <AssemblyType A, IntegrationType I, typename OpBase>
template <AssemblyType A, IntegrationType I, typename OpBase>
OpBase>;
template <AssemblyType A, IntegrationType I, typename OpBase>
MoFEM::OpFluxRhsImpl<ThermoElasticOps::SetTargetTemperature, 1, 1, A, I,
OpBase>,
A, I, OpBase
> {
AddFluxToRhsPipelineImpl() = delete;
boost::ptr_deque<ForcesAndSourcesCore::UserDataOperator> &pipeline,
boost::shared_ptr<VectorDouble> temp_ptr, std::string block_name,
Sev sev
) {
using OP_SOURCE = typename FormsIntegrators<OpBase>::template Assembly<
using OP_TEMP = typename FormsIntegrators<OpBase>::template Assembly<
auto add_op = [&](auto &&meshset_vec_ptr) {
for (
auto m : meshset_vec_ptr) {
std::vector<double> block_data;
m->getAttributes(block_data);
if (block_data.size() < 2) {
"Expected two parameters");
}
double target_temperature = block_data[0];
double beta =
block_data[1];
auto ents_ptr = boost::make_shared<Range>();
*(ents_ptr), true);
<<
"Add " << *
m <<
" target temperature " << target_temperature
<< " penalty " << beta;
pipeline.push_back(new OP_SOURCE(
[target_temperature, beta](double, double, double) {
return target_temperature * beta;
},
ents_ptr));
pipeline.push_back(new OP_TEMP(
[beta](double, double, double) { return -beta; }, ents_ptr));
}
};
m_field.
getInterface<MeshsetsManager>()->getCubitMeshsetPtr(std::regex(
(boost::format("%s(.*)") % block_name).str()
))
);
}
};
template <AssemblyType A, IntegrationType I, typename OpBase>
struct AddFluxToLhsPipelineImpl<
> {
AddFluxToLhsPipelineImpl() = delete;
boost::ptr_deque<ForcesAndSourcesCore::UserDataOperator> &pipeline,
boost::shared_ptr<VectorDouble> temp_ptr, std::string block_name, Sev sev
) {
using OP_MASS = typename FormsIntegrators<OpBase>::template Assembly<
auto add_op = [&](auto &&meshset_vec_ptr) {
for (
auto m : meshset_vec_ptr) {
std::vector<double> block_data;
m->getAttributes(block_data);
if (block_data.size() != 2) {
"Expected two parameters");
}
double beta =
block_data[1];
auto ents_ptr = boost::make_shared<Range>();
*(ents_ptr), true);
<<
"Add " << *
m <<
" penalty " << beta;
pipeline.push_back(new OP_MASS(
[beta](double, double, double) { return -beta; }, ents_ptr));
}
};
m_field.
getInterface<MeshsetsManager>()->getCubitMeshsetPtr(std::regex(
(boost::format("%s(.*)") % block_name).str()
))
);
}
};
template <AssemblyType A, IntegrationType I>
boost::shared_ptr<VectorDouble> dot_T_ptr,
boost::shared_ptr<VectorDouble> T_ptr,
boost::shared_ptr<MatrixDouble> grad_T_ptr,
boost::shared_ptr<double> initial_T_ptr,
boost::shared_ptr<double> peak_T_ptr)
const double vol = getMeasure();
auto t_w = getFTensor0IntegrationWeight();
auto t_coords = getFTensor1CoordsAtGaussPts();
auto t_base = data.getFTensor0N();
auto t_diff_base = data.getFTensor1DiffN<
SPACE_DIM>();
#ifndef NDEBUG
if (data.getDiffN().size1() != data.getN().size1())
if (data.getDiffN().size2() != data.getN().size2() *
SPACE_DIM) {
<< "Side " << rowSide << " " << CN::EntityTypeName(rowType);
MOFEM_LOG(
"SELF", Sev::error) << data.getN();
MOFEM_LOG(
"SELF", Sev::error) << data.getDiffN();
}
#endif
auto t_T = getFTensor0FromVec(*
TPtr);
for (int gg = 0; gg != nbIntegrationPts; ++gg) {
const double alpha = t_w * vol;
t_coords(1), t_coords(2));
int bb = 0;
for (; bb != nbRows; ++bb) {
locF[bb] += (t_base * alpha) * (t_T - set_T);
++t_base;
++t_diff_base;
}
for (; bb < nbRowBaseFunctions; ++bb) {
++t_base;
++t_diff_base;
}
++t_T;
++t_coords;
++t_w;
}
}
private:
boost::shared_ptr<VectorDouble>
dotTPtr;
boost::shared_ptr<VectorDouble>
TPtr;
boost::shared_ptr<MatrixDouble>
gradTPtr;
boost::shared_ptr<MatrixDouble>
gradQPtr;
};
template <AssemblyType A, IntegrationType I>
boost::shared_ptr<VectorDouble> T_ptr)
sYmm = false;
}
EntitiesFieldData::EntData &col_data) {
const double vol = getMeasure();
auto t_w = getFTensor0IntegrationWeight();
auto t_coords = getFTensor1CoordsAtGaussPts();
auto t_row_base = row_data.getFTensor0N();
auto t_row_diff_base = row_data.getFTensor1DiffN<
SPACE_DIM>();
#ifndef NDEBUG
if (row_data.getDiffN().size1() != row_data.getN().size1())
if (row_data.getDiffN().size2() != row_data.getN().size2() *
SPACE_DIM) {
<< "Side " << rowSide << " " << CN::EntityTypeName(rowType);
MOFEM_LOG(
"SELF", Sev::error) << row_data.getN();
MOFEM_LOG(
"SELF", Sev::error) << row_data.getDiffN();
}
if (col_data.getDiffN().size1() != col_data.getN().size1())
if (col_data.getDiffN().size2() != col_data.getN().size2() *
SPACE_DIM) {
<< "Side " << rowSide << " " << CN::EntityTypeName(rowType);
MOFEM_LOG(
"SELF", Sev::error) << col_data.getN();
MOFEM_LOG(
"SELF", Sev::error) << col_data.getDiffN();
}
#endif
auto t_T = getFTensor0FromVec(*
TPtr);
for (int gg = 0; gg != nbIntegrationPts; gg++) {
const double alpha = t_w * vol;
int rr = 0;
for (; rr != nbRows; ++rr) {
auto t_col_base = col_data.getFTensor0N(gg, 0);
auto t_col_diff_base = col_data.getFTensor1DiffN<
SPACE_DIM>(gg, 0);
for (int cc = 0; cc != nbCols; ++cc) {
locMat(rr, cc) += (t_row_base * t_col_base * alpha);
++t_col_base;
++t_col_diff_base;
}
++t_row_base;
++t_row_diff_base;
}
for (; rr < nbRowBaseFunctions; ++rr) {
++t_row_base;
++t_row_diff_base;
}
++t_T;
++t_w;
++t_coords;
}
}
private:
boost::shared_ptr<VectorDouble>
TPtr;
};
#define MOFEM_TAG_AND_LOG(channel, severity, tag)
Tag and log in channel.
constexpr int SPACE_DIM
[Define dimension]
DomainEle::UserDataOperator DomainEleOp
Finire element operator type.
#define CHK_THROW_MESSAGE(err, msg)
Check and throw MoFEM exception.
#define MoFEMFunctionReturnHot(a)
Last executable line of each PETSc function used for error handling. Replaces return()
#define MoFEMFunctionBegin
First executable line of each MoFEM function, used for error handling. Final line of MoFEM functions ...
@ MOFEM_DATA_INCONSISTENCY
#define MoFEMFunctionReturn(a)
Last executable line of each PETSc function used for error handling. Replaces return()
#define CHKERR
Inline error check.
#define MOFEM_LOG(channel, severity)
Log.
#define MOFEM_LOG_CHANNEL(channel)
Set and reset channel.
FTensor::Index< 'i', SPACE_DIM > i
FTensor::Index< 'l', 3 > l
FTensor::Index< 'j', 3 > j
FTensor::Index< 'k', 3 > k
PetscErrorCode MoFEMErrorCode
MoFEM/PETSc error code.
MoFEM::LogManager::SeverityLevel Sev
MoFEMErrorCode addMatThermalBlockOps(MoFEM::Interface &m_field, boost::ptr_deque< ForcesAndSourcesCore::UserDataOperator > &pipeline, std::string block_name, boost::shared_ptr< BlockedThermalParameters > blockedParamsPtr, double default_heat_conductivity, double default_heat_capacity, double default_thermal_conductivity_scale, double default_thermal_capacity_scale, Sev sev, ScalerFunTwoArgs thermal_conductivity_scaling_func, ScalerFunTwoArgs heat_capacity_scaling_func)
MoFEMErrorCode addMatThermoElasticBlockOps(MoFEM::Interface &m_field, boost::ptr_deque< ForcesAndSourcesCore::UserDataOperator > &pipeline, std::string block_name, boost::shared_ptr< BlockedThermoElasticParameters > blockedParamsPtr, double default_coeff_expansion, double default_ref_temp, Sev sev)
constexpr IntegrationType I
constexpr AssemblyType A
[Define dimension]
constexpr auto field_name
FormsIntegrators< DomainEleOp >::Assembly< PETSC >::BiLinearForm< GAUSS >::OpMass< 1, SPACE_DIM > OpMass
[Only used with Hooke equation (linear material model)]
FTensor::Index< 'm', 3 > m
virtual moab::Interface & get_moab()=0
Deprecated interface functions.
Data on single entity (This is passed as argument to DataOperator::doWork)
MoFEMErrorCode getInterface(IFACE *&iface) const
Get interface reference to pointer of interface.
Lhs for setting initial conditions wrt T.
MoFEMErrorCode iNtegrate(EntitiesFieldData::EntData &row_data, EntitiesFieldData::EntData &col_data)
boost::shared_ptr< VectorDouble > TPtr
MoFEMErrorCode iNtegrate(EntitiesFieldData::EntData &data)
boost::shared_ptr< double > peakTPtr
boost::shared_ptr< VectorDouble > dotTPtr
boost::shared_ptr< VectorDouble > TPtr
boost::shared_ptr< MatrixDouble > gradTPtr
boost::shared_ptr< MatrixDouble > gradQPtr
boost::shared_ptr< double > initialTPtr
auto getHeatCapacityPtr()
auto getHeatConductivityScalingPtr()
double heatCapacityScaling
double heatConductivityScaling
auto getHeatCapacityScalingPtr()
auto getHeatConductivityPtr()
auto getCoeffExpansionPtr()
VectorDouble coeffExpansion
boost::shared_ptr< MatrixDouble > mDPtr
boost::shared_ptr< VectorDouble > coeffExpansionPtr
OpKCauchyThermoElasticity(const std::string row_field_name, const std::string col_field_name, boost::shared_ptr< MatrixDouble > mDptr, boost::shared_ptr< VectorDouble > coeff_expansion_ptr)
MoFEMErrorCode iNtegrate(EntitiesFieldData::EntData &row_data, EntitiesFieldData::EntData &col_data)
boost::shared_ptr< double > refTempPtr
boost::shared_ptr< MatrixDouble > strainPtr
DEPRECATED OpStressThermal(const std::string field_name, boost::shared_ptr< MatrixDouble > strain_ptr, boost::shared_ptr< VectorDouble > temp_ptr, boost::shared_ptr< MatrixDouble > m_D_ptr, boost::shared_ptr< VectorDouble > coeff_expansion_ptr, boost::shared_ptr< MatrixDouble > stress_ptr)
MoFEMErrorCode doWork(int side, EntityType type, EntData &data)
[Calculate stress]
boost::shared_ptr< MatrixDouble > stressPtr
boost::shared_ptr< MatrixDouble > mDPtr
boost::shared_ptr< VectorDouble > coeffExpansionPtr
boost::shared_ptr< VectorDouble > tempPtr
FormsIntegrators< DomainEleOp >::Assembly< A >::OpBase AssemblyDomainEleOp
auto init_T
Initialisation function for temperature field.
double default_thermal_conductivity_scale
ScalerFunTwoArgs heat_capacity_scaling
boost::function< double(const double, const double)> ScalerFunTwoArgs
ScalerFunTwoArgs thermal_conductivity_scaling
double default_heat_capacity
double default_coeff_expansion
double default_heat_conductivity