Add heat transfer #108

streeve · 2024-06-28T20:08:29Z

Adds new heat transfer capability; part of #110

New example copies existing thermal deformation example

replacing the body term with a boundary condition
adding heat transfer
new thermal critical timestep

examples/thermomechanics/thermal_deformation.cpp

src/CabanaPD_HeatTransfer.hpp

src/CabanaPD_Particles.hpp

src/CabanaPD_Solver.hpp

src/CabanaPD_Types.hpp

src/force/CabanaPD_ForceModels_PMB.hpp

pabloseleson · 2024-09-03T15:21:46Z

src/CabanaPD_ForceModels.hpp

+    double thermal_coeff;
+    double kappa;
+    double cp;
+    bool constant_conductivity;


I guess this refers to the "micro-conductivity"? Perhaps call it "constant_microconductivity"?

pabloseleson · 2024-09-03T15:23:15Z

src/CabanaPD_ForceModels.hpp

+
+    BaseDynamicTemperatureModel( const double _delta, const double _kappa,
+                                 const double _cp,
+                                 const bool _constant_conductivity = true )


What do we do if we want a different micro-conductivity than the constant one?

pabloseleson · 2024-09-03T15:59:28Z

src/CabanaPD_ForceModels.hpp

+        kappa = _kappa;
+        cp = _cp;
+        const double d3 = _delta * _delta * _delta;
+        thermal_coeff = 9.0 / 2.0 * _kappa / pi / d3;


This should be analogous to Line 52 in CabanaPD_ForceModels_PMB.hpp. I was wondering if we should use a more clear description. There, we used "c". However using "k" may not be good.

pabloseleson · 2024-09-03T16:00:52Z

src/CabanaPD_ForceModels.hpp

+        constant_conductivity = _constant_conductivity;
+    }
+
+    KOKKOS_INLINE_FUNCTION double conductivity_function( double r ) const


Should the function be called "microconductivity_function"?

pabloseleson · 2024-09-03T16:03:51Z

src/CabanaPD_HeatTransfer.hpp

+    }
+
+    template <class ParticleType>
+    void stepEuler( const ParticleType& particles, const double dt )


Note we are using "forward" Euler

pabloseleson · 2024-09-03T17:02:36Z

src/CabanaPD_HeatTransfer.hpp

+
+            const double coeff =
+                model.thermal_coeff * model.conductivity_function( xi );
+            conduction( i ) +=


Where is conduction(i) initialized? Is this in Line 111: Cabana::deep_copy( conduction, 0.0 ); ?

Yes, that's correct

pabloseleson · 2024-09-03T17:29:51Z

src/CabanaPD_Particles.hpp

@@ -672,8 +675,8 @@ class Particles<MemorySpace, PMB, TemperatureDependent, Dimension>

    // These are split since weighted volume only needs to be communicated once
    // and dilatation only needs to be communicated for LPS.
-    using scalar_type = typename base_type::scalar_type;
-    using aosoa_temp_type = Cabana::AoSoA<scalar_type, memory_space, 1>;
+    using temp_types = Cabana::MemberTypes<double, double>;


What is this change for?

We need to store the temperature diffusion separate from the current temperature

pabloseleson · 2024-09-03T17:50:49Z

src/force/CabanaPD_ForceModels_PMB.hpp

@@ -252,6 +252,135 @@ auto createForceModel( PMB, Fracture, ParticleType particles,
        delta, K, G0, temp, alpha, temp0 );
 }

+template <typename TemperatureType>
+struct ForceModel<PMB, Elastic, DynamicTemperature, TemperatureType>


I got confused about this. The heat transfer does not introduce a new mechanics model. What is this part for?

All model details are included in the same object - mechanical and thermal. And confirming your point, the code below mostly just combines the two existing models

pabloseleson · 2024-09-06T16:53:29Z

The difference between the critical time step of heat transfer and mechanics requires:
(1) A multi-rate time-stepping scheme, where heat transfer is solved every number of time steps. Otherwise, the mechanics time step would be too small for the heat transfer. Thus will allow to solve both the heat transfer and the mechanics.
(2) The mechanics time step may be too small for actual applications, so we may consider implicit time-stepping.

… heat transfer example

streeve added the enhancement New feature or request label Jun 28, 2024

streeve requested a review from pabloseleson June 28, 2024 20:08

streeve self-assigned this Jun 28, 2024