Changeset 4697 for palm/trunk

Timestamp:

Sep 25, 2020 8:24:29 AM (4 years ago)

Author:

suehring

Message:

To avoid numerical oscillations which may lead to a built-up of passive scalar near non-cyclic boundaries, employ a first-order scheme at the 3 grid points next to the boundary for passive scalars

File:

• palm/trunk/SOURCE/advec_ws.f90 (modified) (6 diffs)

palm/trunk/SOURCE/advec_ws.f90

@@ -19 +19 @@
 ! Current revisions:
 ! ------------------
-! 
-! 
+!
+!
 ! Former revisions:
 ! -----------------
 ! $Id$
+! To avoid numerical oscillations which may lead to a built-up of passive scalar near non-cyclic
+! boundaries, employ a first-order scheme at the 3 grid points next to the boundary for passive
+! scalars
+! 
+! 4581 2020-06-29 08:49:58Z suehring
 ! Enable output of resolved-scale vertical fluxes of chemical species.
 ! 
@@ -1043 +1048 @@
 
 !
-!--             Near lateral boundary flags might be overwritten. Set them again.
+!--             Near lateral boundaries set the flags again. In order to avoid strong numerical 
+!--             oscillations near the boundaries, which may lead to scalar built-up, also employ
+!--             extended degradation zones here.
 !--             x-direction
-                IF ( ( non_cyclic_l  .AND.  i == 0  )  .OR.                                        &
-                     ( non_cyclic_r  .AND.  i == nx ) )  THEN
+                IF ( ( non_cyclic_l  .AND.  i <= 3  )  .OR.                                        &
+                     ( non_cyclic_r  .AND.  i >= nx-3 ) )  THEN
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 0 )
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 1 )
@@ -1054 +1061 @@
                 ENDIF
 
-                IF ( ( non_cyclic_l  .AND.  i == 1    )  .OR.                                      &
-                     ( non_cyclic_r  .AND.  i == nx-1 ) )  THEN
+                IF ( ( non_cyclic_l  .AND.  i == 4    )  .OR.                                      &
+                     ( non_cyclic_r  .AND.  i == nx-4 ) )  THEN
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 0 )
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 1 )
@@ -1064 +1071 @@
 !
 !--             y-direction
-                IF ( ( non_cyclic_n  .AND.  j == 0  )  .OR.                                        &
-                     ( non_cyclic_s  .AND.  j == ny ) )  THEN
+                IF ( ( non_cyclic_n  .AND.  j <= 3  )  .OR.                                        &
+                     ( non_cyclic_s  .AND.  j >= ny-3 ) )  THEN
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 3 )
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 4 )
@@ -1073 +1080 @@
                 ENDIF
 
-                IF ( ( non_cyclic_n  .AND.  j == 1    )  .OR.                                      &
-                     ( non_cyclic_s  .AND.  j == ny-1 ) )  THEN
+                IF ( ( non_cyclic_n  .AND.  j == 4    )  .OR.                                      &
+                     ( non_cyclic_s  .AND.  j == ny-4 ) )  THEN
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 3 )
                    advc_flag(k,j,i) = IBCLR( advc_flag(k,j,i), 4 )
@@ -1083 +1090 @@
 
              ENDIF
-
-
 !
 !--          scalar - z-direction. Fluxes are calculated on w-grid level. Boundary values at/within