pbl: comments about differences between explicit and implicit boussinesq

Author: pdziekan

libmpdata++/solvers/detail/boussinesq_expl.hpp

@@ -4,6 +4,9 @@
  * @section LICENSE
  * GPLv3+ (see the COPYING file or http://www.gnu.org/licenses/)
  */
+
+// explicit - ix::tht is theta
+
 #pragma once
 #include <libmpdata++/solvers/detail/boussinesq_sgs_common.hpp>
 

libmpdata++/solvers/detail/boussinesq_impl.hpp

@@ -4,6 +4,11 @@
  * @section LICENSE
  * GPLv3+ (see the COPYING file or http://www.gnu.org/licenses/)
  */
+
+// implicit - ix::tht is the perturbation of theta, i.e. (theta - theta_env)
+//            compared with explicit modeling of theta, this leads to additional forcing
+//            w * dz(theta_env)
+
 #pragma once
 #include <libmpdata++/solvers/detail/boussinesq_sgs_common.hpp>
 

tests/sandbox/pbl/pbl_test_def.hpp

@@ -135,6 +135,12 @@ void test(const std::string &dirname, const int np, const int nt)
     slv.advectee(ix::u) = 0;
     slv.advectee(ix::v) = 0; 
 
+    // for explicit boussinesq (impl_tht == false), ix::tht needs to be full theta (not perturbation)
+    /*
+     *  blitz::thirdIndex k;
+     *  slv.advectee(ix::tht) += 300 * where(k * p.dk <= mixed_length, 1, 1 + (k * p.dk - mixed_length) * st);
+    */
+
     {
       blitz::thirdIndex k;
       // environmental potential temperature profile