Closes #303. Adds functions to get surface emissivity and radiative heat flux.

src/gsi/GasSurfaceInteraction.cpp

@@ -216,6 +216,18 @@ void GasSurfaceInteraction::getMassBlowingRate(double& mdot){
 
 //==============================================================================
 
+void GasSurfaceInteraction::getRadiativeHeatFlux(double& qrad){
+    qrad = mp_surf->radiativeHeatFlux();
+}
+
+//==============================================================================
+
+void GasSurfaceInteraction::getSurfaceEmissivity(double& eps){
+    eps = mp_surf->surfaceEmissivity();
+}
+
+//==============================================================================
+
 inline void GasSurfaceInteraction::errorWrongTypeofGSIFile(
     const std::string& gsi_root_tag)
 {

src/gsi/GasSurfaceInteraction.h

@@ -179,6 +179,20 @@ class GasSurfaceInteraction
      */
     void getMassBlowingRate(double& mdot);
 
+    /**
+     * Function which returns the total radiative flux.
+     *
+     * @param qrad on return radiative heat flux W/m^2
+     */
+    void getRadiativeHeatFlux(double& qrad);
+
+    /**
+     * Function which returns the surface emissivity.
+     *
+     * @param eps on return surface emissivity
+     */
+    void getSurfaceEmissivity(double& eps);
+
 private:
     /**
      * Error function; wrong type of Gas Surface Interaction input file.

src/gsi/Surface.h

@@ -193,6 +193,30 @@ class Surface
      */
     virtual double massBlowingRate() = 0;
 
+//==============================================================================
+
+    /**
+     * Purely virtual function returning the net radiative heat flux.
+     */
+    virtual double radiativeHeatFlux()
+    {
+        throw LogicError()
+        << "radiativeHeatFlux can be called only when solving "
+        << "the surface energy balance!";
+    }
+
+//==============================================================================
+
+    /**
+     * Purely virtual function returning the surface emissivity.
+     */
+    virtual double surfaceEmissivity()
+    {
+        throw LogicError()
+        << "emissivity can be called only when solving "
+        << "the surface energy balance!";
+    }
+
 //==============================================================================
 
 };

src/gsi/SurfaceBalanceSolverMassEnergy.cpp

@@ -239,6 +239,24 @@ class SurfaceBalanceSolverMassEnergy :
         return 0.;
     }
 
+//==============================================================================
+
+    double radiativeHeatFlux()
+    {
+        if (mp_surf_rad != NULL)
+            return mp_surf_rad->surfaceNetRadiativeHeatFlux();
+        return 0.;
+    }
+
+//==============================================================================
+
+    double surfaceEmissivity()
+    {
+        if (mp_surf_rad != NULL)
+            return mp_surf_rad->surfaceEmissivity();
+        return 0.;
+    }
+
 //==============================================================================
 
     void updateFunction(Eigen::VectorXd& v_X)

src/gsi/SurfaceRadiation.cpp

@@ -72,5 +72,12 @@ double SurfaceRadiation::surfaceNetRadiativeHeatFlux()
     return m_eps * (Mutation::SB * std::pow(T_surf, 4.0) - m_gas_rad_heat_flux);
 }
 
+//==============================================================================
+
+double SurfaceRadiation::surfaceEmissivity()
+{
+    return m_eps;
+}
+
     } // namespace GasSurfaceInteraction
 } // namespace Mutation

src/gsi/SurfaceRadiation.h

@@ -73,6 +73,12 @@ class SurfaceRadiation
      */
     double surfaceNetRadiativeHeatFlux();
 
+//==============================================================================
+    /**
+     *  Function which returns the surface emissivity.
+     */
+    double surfaceEmissivity();
+
 //==============================================================================
     /**
      *  Function which takes the incoming radiative heat from the gas .