Changeset 1159 for palm/trunk/SOURCE/boundary_conds.f90

Timestamp:

May 21, 2013 11:58:22 AM (11 years ago)

Author:

fricke

Message:

Bugfix: In case of non-cyclic lateral boundary conditions, Neumann boundary conditions for the velocity components at the outflow are in fact radiation boundary conditions using the maximum phase velocity that ensures numerical stability (CFL-condition).
Logical operator use_cmax is now used instead of bc_lr_dirneu/_neudir.

File:

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

palm/trunk/SOURCE/boundary_conds.f90

@@ -20 +20 @@
 ! Current revisions:
 ! -----------------
+! Bugfix: Neumann boundary conditions for the velocity components at the
+! outflow are in fact radiation boundary conditions using the maximum phase
+! velocity that ensures numerical stability (CFL-condition).
+! Hence, logical operator use_cmax is now used instead of bc_lr_dirneu/_neudir.
+! Bugfix: In case of use_cmax at the outflow, u, v, w are replaced by
+! u_p, v_p, w_p  
 !
 !  
@@ -96 +102 @@
 ! Description:
 ! ------------
-! Boundary conditions for the prognostic quantities (range='main').
-! In case of non-cyclic lateral boundaries the conditions for velocities at
-! the outflow are set after the pressure solver has been called (range=
-! 'outflow_uvw').
+! Boundary conditions for the prognostic quantities.
 ! One additional bottom boundary condition is applied for the TKE (=(u*)**2)
 ! in prandtl_fluxes. The cyclic lateral boundary conditions are implicitly
@@ -334 +337 @@
 
 !
-!-- Neumann or Radiation boundary condition for the velocities at the 
-!-- respective outflow
+!-- Radiation boundary conditions for the velocities at the respective outflow.
+!-- The phase velocity is either assumed to the maximum phase velocity that
+!-- ensures numerical stability (CFL-condition) or calculated after
+!-- Orlanski(1976) and averaged along the outflow boundary.
     IF ( outflow_s )  THEN
 
-       IF ( bc_ns_dirneu )  THEN
-          u(:,-1,:) = u(:,0,:)
-          v(:,0,:)  = v(:,1,:)
-          w(:,-1,:) = w(:,0,:)          
-       ELSEIF ( bc_ns_dirrad )  THEN
+       IF ( use_cmax )  THEN
+          u_p(:,-1,:) = u(:,0,:)
+          v_p(:,0,:)  = v(:,1,:)
+          w_p(:,-1,:) = w(:,0,:)          
+       ELSEIF ( .NOT. use_cmax )  THEN
 
           c_max = dy / dt_3d
@@ -477 +482 @@
     IF ( outflow_n )  THEN
 
-       IF ( bc_ns_neudir )  THEN
-          u(:,ny+1,:) = u(:,ny,:)
-          v(:,ny+1,:) = v(:,ny,:)
-          w(:,ny+1,:) = w(:,ny,:)          
-       ELSEIF ( bc_ns_dirrad )  THEN
+       IF ( use_cmax )  THEN
+          u_p(:,ny+1,:) = u(:,ny,:)
+          v_p(:,ny+1,:) = v(:,ny,:)
+          w_p(:,ny+1,:) = w(:,ny,:)          
+       ELSEIF ( .NOT. use_cmax )  THEN
 
           c_max = dy / dt_3d
@@ -616 +621 @@
     IF ( outflow_l )  THEN
 
-       IF ( bc_lr_neudir )  THEN
-          u(:,:,-1) = u(:,:,0)
-          v(:,:,0)  = v(:,:,1)
-          w(:,:,-1) = w(:,:,0)          
-       ELSEIF ( bc_ns_dirrad )  THEN
+       IF ( use_cmax )  THEN
+          u_p(:,:,-1) = u(:,:,0)
+          v_p(:,:,0)  = v(:,:,1)
+          w_p(:,:,-1) = w(:,:,0)          
+       ELSEIF ( .NOT. use_cmax )  THEN
 
           c_max = dx / dt_3d
@@ -755 +760 @@
     IF ( outflow_r )  THEN
 
-       IF ( bc_lr_dirneu )  THEN
-          u(:,:,nx+1) = u(:,:,nx)
-          v(:,:,nx+1) = v(:,:,nx)
-          w(:,:,nx+1) = w(:,:,nx)          
-       ELSEIF ( bc_ns_dirrad )  THEN
+       IF ( use_cmax )  THEN
+          u_p(:,:,nx+1) = u(:,:,nx)
+          v_p(:,:,nx+1) = v(:,:,nx)
+          w_p(:,:,nx+1) = w(:,:,nx)          
+       ELSEIF ( .NOT. use_cmax )  THEN
 
           c_max = dx / dt_3d