Merge pull request #751 from MESAHub/EbF/reimplement_drag_in_riemann_hydro

reimplement drag in riemann hydro

Author: Debraheem

docs/source/changelog.rst

@@ -19,6 +19,8 @@ New Features
 
 ``mesa_reader`` can now be installed with ``pip``.
 
+A pseudo drag term ``v_drag`` has been reintroduced for ``u_flag`` to damp spurious shocks.
+
 .. _Bug Fixes main:
 
 Bug Fixes

star/defaults/controls.defaults

@@ -2985,7 +2985,7 @@
     conv_premix_dump_snapshots = .false.
 
 
-   ! Rayleigh Taylor Instability
+   ! Rayleigh-Taylor Instability
    ! ____________________________
 
       ! derived from Paul Duffell's code RT1D.
@@ -4135,6 +4135,27 @@
     D_mix_rotation_min_logT_full_off = 9.5d0
 
 
+      ! D_mix_rotation_min_tau_full_off
+      ! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+      ! Drop rotational components of ``D_mix`` for locations where tau <= this.
+      ! For numerical stability, turn off rotational part of ``D_mix`` at very low tau.
+
+      ! ::
+      
+    D_mix_rotation_min_tau_full_off = 0d0
+    
+          ! D_mix_rotation_max_tau_full_on
+      ! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+      ! Use rotational components of ``D_mix`` for locations where tau >= this.
+      ! For numerical stability, turn off rotational part of ``D_mix`` at very low tau.
+
+      ! ::
+      
+    D_mix_rotation_min_tau_full_on = 0d0
+
+
       ! D_omega_max_replacement_fraction
       ! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
       ! D_omega_growth_rate
@@ -8241,15 +8262,18 @@
       ! ::
 
     use_dPrad_dm_form_of_T_gradient_eqn = .false.
-    use_gradT_actual_vs_gradT_MLT_for_T_gradient_eqn = .false.
-
-
+    use_gradT_actual_vs_gradT_MLT_for_T_gradient_eqn = .false.    
+  
+  
+      ! Hydrodynamic drag
+      ! =================
+      
       ! drag_coefficient
       ! ~~~~~~~~~~~~~~~~
       ! min_q_for_drag
       ! ~~~~~~~~~~~~~~
 
-      ! only when v_flag.  adjusts both v and energy transfer from kinetic to thermal.
+      ! only when v_flag = .true.. Adjusts both v and energy transfer from kinetic to thermal.
       ! only for v(k) when q(k) > min_q_for_drag.
       ! kill off fraction of v = drag_coefficient (i.e. set to 1 to keep v near 0)
       ! useful for preventing the development radial pulsations during advanced
@@ -8274,13 +8298,35 @@
     use_drag_energy = .true.
     drag_coefficient = 0d0
     min_q_for_drag = 0d0
+    
+ 
+      ! v_drag_factor
+      ! ~~~~~~~~~~~~~
+      ! v_drag
+      ! ~~~~~~
+      ! q_for_v_drag_full_off
+      ! ~~~~~~~~~~~~~~~~~~~~~
+      ! q_for_v_drag_full_on
+      ! ~~~~~~~~~~~~~~~~~~~~
 
 
-      ! for hydro comparison tests (e.g., Sedov)
+      ! Only when u_flag = .true.. Adds a pseudo drag term of the form
+      ! -v_drag_factor*(v-v_drag)^2/r, can be used damp velocities in outer layers
+      ! of a star, useful for smoothing out spurious shocks colliding in ejected layers. 
+      ! Effect is full on for q>q_for_v_drag_full_on and full off for
+      ! q < q_for_v_drag_full_off.
+
+      ! ::
+
+    v_drag_factor = 0d0
+    v_drag = 0d0
+    q_for_v_drag_full_off = 0.95d0
+    q_for_v_drag_full_on = 0.96d0
 
 
       ! Rayleigh-Taylor Instability
       ! ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+      ! for hydro comparison tests (e.g., Sedov)
       ! RTI_A
       ! ~~~~~
       ! RTI_B

star/dev_cases_star_to_RSP2/dev_BEP/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none
 

star/dev_cases_star_to_RSP2/dev_BW_Vul/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none
 
@@ -185,7 +185,7 @@ end subroutine extras_startup
       subroutine gyre_linear_analysis_and_set_velocities(s,restart,ierr)
          use const_def
          use math_lib
-         use gyre_lib
+         use gyre_mesa_m
          type (star_info), pointer :: s
          logical, intent(in) :: restart
          integer, intent(out) :: ierr

star/dev_cases_star_to_RSP2/dev_Cepheid/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none
 
@@ -514,7 +514,7 @@ end subroutine data_for_extra_profile_columns
       subroutine gyre_linear_analysis_and_set_velocities(s,restart,ierr)
          use const_def
          use math_lib
-         use gyre_lib
+         use gyre_mesa_m
          type (star_info), pointer :: s
          logical, intent(in) :: restart
          integer, intent(out) :: ierr

star/dev_cases_star_to_RSP2/dev_Cepheid_6M/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none
 

star/dev_cases_star_to_RSP2/dev_Cepheid_9M/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none
 

star/dev_cases_star_to_RSP2/dev_Delta_Scuti/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none
 

star/dev_cases_star_to_RSP2/dev_Mira/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none
 

star/dev_cases_star_to_RSP2/dev_RR_Lyrae/src/run_star_extras.f90

@@ -26,7 +26,7 @@ module run_star_extras
       use star_def
       use const_def
       use math_lib
-      use gyre_lib
+      use gyre_mesa_m
 
       implicit none