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diffusion_v.f90 @ 1257

Last change on this file since 1257 was 1257, checked in by raasch, 10 years ago

New:
---

openACC porting of timestep calculation
(modules, timestep, time_integration)

Changed:

openACC loop directives and vector clauses removed (because they do not give any performance improvement with PGI
compiler versions > 13.6)
(advec_ws, buoyancy, coriolis, diffusion_e, diffusion_s, diffusion_u, diffusion_v, diffusion_w, diffusivities, exchange_horiz, fft_xy, pres, production_e, transpose, tridia_solver, wall_fluxes)

openACC loop independent clauses added
(boundary_conds, prandtl_fluxes, pres)

openACC declare create statements moved after FORTRAN declaration statement
(diffusion_u, diffusion_v, diffusion_w, fft_xy, poisfft, production_e, tridia_solver)

openACC end parallel replaced by end parallel loop
(flow_statistics, pres)

openACC "kernels do" replaced by "kernels loop"
(prandtl_fluxes)

output format for theta* changed to avoid output of *
(run_control)

Errors:

bugfix for calculation of advective timestep (old version may cause wrong timesteps in case of
vertixcally stretched grids)
Attention: standard run-control output has changed!
(timestep)

Property svn:keywords set to Id

File size: 24.3 KB

Line
1	MODULE diffusion_v_mod
2
3	!--------------------------------------------------------------------------------!
4	! This file is part of PALM.
5	!
6	! PALM is free software: you can redistribute it and/or modify it under the terms
7	! of the GNU General Public License as published by the Free Software Foundation,
8	! either version 3 of the License, or (at your option) any later version.
9	!
10	! PALM is distributed in the hope that it will be useful, but WITHOUT ANY
11	! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12	! A PARTICULAR PURPOSE. See the GNU General Public License for more details.
13	!
14	! You should have received a copy of the GNU General Public License along with
15	! PALM. If not, see <http://www.gnu.org/licenses/>.
16	!
17	! Copyright 1997-2012 Leibniz University Hannover
18	!--------------------------------------------------------------------------------!
19	!
20	! Current revisions:
21	! -----------------
22	! openacc loop and loop vector clauses removed, declare create moved after
23	! the FORTRAN declaration statement
24	!
25	! Former revisions:
26	! -----------------
27	! $Id: diffusion_v.f90 1257 2013-11-08 15:18:40Z raasch $
28	!
29	! 1128 2013-04-12 06:19:32Z raasch
30	! loop index bounds in accelerator version replaced by i_left, i_right, j_south,
31	! j_north
32	!
33	! 1036 2012-10-22 13:43:42Z raasch
34	! code put under GPL (PALM 3.9)
35	!
36	! 1015 2012-09-27 09:23:24Z raasch
37	! accelerator version (*_acc) added
38	!
39	! 1001 2012-09-13 14:08:46Z raasch
40	! arrays comunicated by module instead of parameter list
41	!
42	! 978 2012-08-09 08:28:32Z fricke
43	! outflow damping layer removed
44	! kmxm_x/_y and kmxp_x/_y change to kmxm and kmxp
45	!
46	! 667 2010-12-23 12:06:00Z suehring/gryschka
47	! nxl-1, nxr+1, nys-1, nyn+1 replaced by nxlg, nxrg, nysg, nyng
48	!
49	! 366 2009-08-25 08:06:27Z raasch
50	! bc_lr replaced by bc_lr_cyc
51	!
52	! 106 2007-08-16 14:30:26Z raasch
53	! Momentumflux at top (vswst) included as boundary condition,
54	! j loop is starting from nysv (needed for non-cyclic boundary conditions)
55	!
56	! 75 2007-03-22 09:54:05Z raasch
57	! Wall functions now include diabatic conditions, call of routine wall_fluxes,
58	! z0 removed from argument list, vynp eliminated
59	!
60	! 20 2007-02-26 00:12:32Z raasch
61	! Bugfix: ddzw dimensioned 1:nzt"+1"
62	!
63	! RCS Log replace by Id keyword, revision history cleaned up
64	!
65	! Revision 1.15 2006/02/23 10:36:00 raasch
66	! nzb_2d replaced by nzb_v_outer in horizontal diffusion and by nzb_v_inner
67	! or nzb_diff_v, respectively, in vertical diffusion,
68	! wall functions added for north and south walls, +z0 in argument list,
69	! terms containing w(k-1,..) are removed from the Prandtl-layer equation
70	! because they cause errors at the edges of topography
71	! WARNING: loops containing the MAX function are still not properly vectorized!
72	!
73	! Revision 1.1 1997/09/12 06:24:01 raasch
74	! Initial revision
75	!
76	!
77	! Description:
78	! ------------
79	! Diffusion term of the v-component
80	!------------------------------------------------------------------------------!
81
82	USE wall_fluxes_mod
83
84	PRIVATE
85	PUBLIC diffusion_v, diffusion_v_acc
86
87	INTERFACE diffusion_v
88	MODULE PROCEDURE diffusion_v
89	MODULE PROCEDURE diffusion_v_ij
90	END INTERFACE diffusion_v
91
92	INTERFACE diffusion_v_acc
93	MODULE PROCEDURE diffusion_v_acc
94	END INTERFACE diffusion_v_acc
95
96	CONTAINS
97
98
99	!------------------------------------------------------------------------------!
100	! Call for all grid points
101	!------------------------------------------------------------------------------!
102	SUBROUTINE diffusion_v
103
104	USE arrays_3d
105	USE control_parameters
106	USE grid_variables
107	USE indices
108
109	IMPLICIT NONE
110
111	INTEGER :: i, j, k
112	REAL :: kmxm, kmxp, kmzm, kmzp
113
114	REAL, DIMENSION(nzb:nzt+1,nys:nyn,nxl:nxr) :: vsus
115
116	!
117	!-- First calculate horizontal momentum flux v'u' at vertical walls,
118	!-- if neccessary
119	IF ( topography /= 'flat' ) THEN
120	CALL wall_fluxes( vsus, 0.0, 1.0, 0.0, 0.0, nzb_v_inner, &
121	nzb_v_outer, wall_v )
122	ENDIF
123
124	DO i = nxl, nxr
125	DO j = nysv, nyn
126	!
127	!-- Compute horizontal diffusion
128	DO k = nzb_v_outer(j,i)+1, nzt
129	!
130	!-- Interpolate eddy diffusivities on staggered gridpoints
131	kmxp = 0.25 * &
132	( km(k,j,i)+km(k,j,i+1)+km(k,j-1,i)+km(k,j-1,i+1) )
133	kmxm = 0.25 * &
134	( km(k,j,i)+km(k,j,i-1)+km(k,j-1,i)+km(k,j-1,i-1) )
135
136	tend(k,j,i) = tend(k,j,i) &
137	& + ( kmxp * ( v(k,j,i+1) - v(k,j,i) ) * ddx &
138	& + kmxp * ( u(k,j,i+1) - u(k,j-1,i+1) ) * ddy &
139	& - kmxm * ( v(k,j,i) - v(k,j,i-1) ) * ddx &
140	& - kmxm * ( u(k,j,i) - u(k,j-1,i) ) * ddy &
141	& ) * ddx &
142	& + 2.0 * ( &
143	& km(k,j,i) * ( v(k,j+1,i) - v(k,j,i) ) &
144	& - km(k,j-1,i) * ( v(k,j,i) - v(k,j-1,i) ) &
145	& ) * ddy2
146	ENDDO
147
148	!
149	!-- Wall functions at the left and right walls, respectively
150	IF ( wall_v(j,i) /= 0.0 ) THEN
151
152	DO k = nzb_v_inner(j,i)+1, nzb_v_outer(j,i)
153	kmxp = 0.25 * &
154	( km(k,j,i)+km(k,j,i+1)+km(k,j-1,i)+km(k,j-1,i+1) )
155	kmxm = 0.25 * &
156	( km(k,j,i)+km(k,j,i-1)+km(k,j-1,i)+km(k,j-1,i-1) )
157
158	tend(k,j,i) = tend(k,j,i) &
159	+ 2.0 * ( &
160	km(k,j,i) * ( v(k,j+1,i) - v(k,j,i) ) &
161	- km(k,j-1,i) * ( v(k,j,i) - v(k,j-1,i) ) &
162	) * ddy2 &
163	+ ( fxp(j,i) * ( &
164	kmxp * ( v(k,j,i+1) - v(k,j,i) ) * ddx &
165	+ kmxp * ( u(k,j,i+1) - u(k,j-1,i+1) ) * ddy &
166	) &
167	- fxm(j,i) * ( &
168	kmxm * ( v(k,j,i) - v(k,j,i-1) ) * ddx &
169	+ kmxm * ( u(k,j,i) - u(k,j-1,i) ) * ddy &
170	) &
171	+ wall_v(j,i) * vsus(k,j,i) &
172	) * ddx
173	ENDDO
174	ENDIF
175
176	!
177	!-- Compute vertical diffusion. In case of simulating a Prandtl
178	!-- layer, index k starts at nzb_v_inner+2.
179	DO k = nzb_diff_v(j,i), nzt_diff
180	!
181	!-- Interpolate eddy diffusivities on staggered gridpoints
182	kmzp = 0.25 * &
183	( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
184	kmzm = 0.25 * &
185	( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
186
187	tend(k,j,i) = tend(k,j,i) &
188	& + ( kmzp * ( ( v(k+1,j,i) - v(k,j,i) ) * ddzu(k+1) &
189	& + ( w(k,j,i) - w(k,j-1,i) ) * ddy &
190	& ) &
191	& - kmzm * ( ( v(k,j,i) - v(k-1,j,i) ) * ddzu(k) &
192	& + ( w(k-1,j,i) - w(k-1,j-1,i) ) * ddy &
193	& ) &
194	& ) * ddzw(k)
195	ENDDO
196
197	!
198	!-- Vertical diffusion at the first grid point above the surface,
199	!-- if the momentum flux at the bottom is given by the Prandtl law
200	!-- or if it is prescribed by the user.
201	!-- Difference quotient of the momentum flux is not formed over
202	!-- half of the grid spacing (2.0*ddzw(k)) any more, since the
203	!-- comparison with other (LES) modell showed that the values of
204	!-- the momentum flux becomes too large in this case.
205	!-- The term containing w(k-1,..) (see above equation) is removed here
206	!-- because the vertical velocity is assumed to be zero at the surface.
207	IF ( use_surface_fluxes ) THEN
208	k = nzb_v_inner(j,i)+1
209	!
210	!-- Interpolate eddy diffusivities on staggered gridpoints
211	kmzp = 0.25 * &
212	( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
213	kmzm = 0.25 * &
214	( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
215
216	tend(k,j,i) = tend(k,j,i) &
217	& + ( kmzp * ( w(k,j,i) - w(k,j-1,i) ) * ddy &
218	& ) * ddzw(k) &
219	& + ( kmzp * ( v(k+1,j,i) - v(k,j,i) ) * ddzu(k+1) &
220	& + vsws(j,i) &
221	& ) * ddzw(k)
222	ENDIF
223
224	!
225	!-- Vertical diffusion at the first gridpoint below the top boundary,
226	!-- if the momentum flux at the top is prescribed by the user
227	IF ( use_top_fluxes .AND. constant_top_momentumflux ) THEN
228	k = nzt
229	!
230	!-- Interpolate eddy diffusivities on staggered gridpoints
231	kmzp = 0.25 * &
232	( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
233	kmzm = 0.25 * &
234	( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
235
236	tend(k,j,i) = tend(k,j,i) &
237	& - ( kmzm * ( w(k-1,j,i) - w(k-1,j-1,i) ) * ddy &
238	& ) * ddzw(k) &
239	& + ( -vswst(j,i) &
240	& - kmzm * ( v(k,j,i) - v(k-1,j,i) ) * ddzu(k) &
241	& ) * ddzw(k)
242	ENDIF
243
244	ENDDO
245	ENDDO
246
247	END SUBROUTINE diffusion_v
248
249
250	!------------------------------------------------------------------------------!
251	! Call for all grid points - accelerator version
252	!------------------------------------------------------------------------------!
253	SUBROUTINE diffusion_v_acc
254
255	USE arrays_3d
256	USE control_parameters
257	USE grid_variables
258	USE indices
259
260	IMPLICIT NONE
261
262	INTEGER :: i, j, k
263	REAL :: kmxm, kmxp, kmzm, kmzp
264
265	REAL, DIMENSION(nzb:nzt+1,nys:nyn,nxl:nxr) :: vsus
266	!$acc declare create ( vsus )
267
268	!
269	!-- First calculate horizontal momentum flux v'u' at vertical walls,
270	!-- if neccessary
271	IF ( topography /= 'flat' ) THEN
272	CALL wall_fluxes_acc( vsus, 0.0, 1.0, 0.0, 0.0, nzb_v_inner, &
273	nzb_v_outer, wall_v )
274	ENDIF
275
276	!$acc kernels present ( u, v, w, km, tend, vsws, vswst ) &
277	!$acc present ( ddzu, ddzw, fxm, fxp, wall_v ) &
278	!$acc present ( nzb_v_inner, nzb_v_outer, nzb_diff_v )
279	DO i = i_left, i_right
280	DO j = j_south, j_north
281	!
282	!-- Compute horizontal diffusion
283	DO k = 1, nzt
284	IF ( k > nzb_v_outer(j,i) ) THEN
285	!
286	!-- Interpolate eddy diffusivities on staggered gridpoints
287	kmxp = 0.25 * &
288	( km(k,j,i)+km(k,j,i+1)+km(k,j-1,i)+km(k,j-1,i+1) )
289	kmxm = 0.25 * &
290	( km(k,j,i)+km(k,j,i-1)+km(k,j-1,i)+km(k,j-1,i-1) )
291
292	tend(k,j,i) = tend(k,j,i) &
293	& + ( kmxp * ( v(k,j,i+1) - v(k,j,i) ) * ddx &
294	& + kmxp * ( u(k,j,i+1) - u(k,j-1,i+1) ) * ddy &
295	& - kmxm * ( v(k,j,i) - v(k,j,i-1) ) * ddx &
296	& - kmxm * ( u(k,j,i) - u(k,j-1,i) ) * ddy &
297	& ) * ddx &
298	& + 2.0 * ( &
299	& km(k,j,i) * ( v(k,j+1,i) - v(k,j,i) ) &
300	& - km(k,j-1,i) * ( v(k,j,i) - v(k,j-1,i) ) &
301	& ) * ddy2
302	ENDIF
303	ENDDO
304
305	!
306	!-- Wall functions at the left and right walls, respectively
307	DO k = 1, nzt
308	IF( k > nzb_v_inner(j,i) .AND. k <= nzb_v_outer(j,i) .AND. &
309	wall_v(j,i) /= 0.0 ) THEN
310
311	kmxp = 0.25 * &
312	( km(k,j,i)+km(k,j,i+1)+km(k,j-1,i)+km(k,j-1,i+1) )
313	kmxm = 0.25 * &
314	( km(k,j,i)+km(k,j,i-1)+km(k,j-1,i)+km(k,j-1,i-1) )
315
316	tend(k,j,i) = tend(k,j,i) &
317	+ 2.0 * ( &
318	km(k,j,i) * ( v(k,j+1,i) - v(k,j,i) ) &
319	- km(k,j-1,i) * ( v(k,j,i) - v(k,j-1,i) ) &
320	) * ddy2 &
321	+ ( fxp(j,i) * ( &
322	kmxp * ( v(k,j,i+1) - v(k,j,i) ) * ddx &
323	+ kmxp * ( u(k,j,i+1) - u(k,j-1,i+1) ) * ddy &
324	) &
325	- fxm(j,i) * ( &
326	kmxm * ( v(k,j,i) - v(k,j,i-1) ) * ddx &
327	+ kmxm * ( u(k,j,i) - u(k,j-1,i) ) * ddy &
328	) &
329	+ wall_v(j,i) * vsus(k,j,i) &
330	) * ddx
331	ENDIF
332	ENDDO
333
334	!
335	!-- Compute vertical diffusion. In case of simulating a Prandtl
336	!-- layer, index k starts at nzb_v_inner+2.
337	DO k = 1, nzt_diff
338	IF ( k >= nzb_diff_v(j,i) ) THEN
339	!
340	!-- Interpolate eddy diffusivities on staggered gridpoints
341	kmzp = 0.25 * &
342	( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
343	kmzm = 0.25 * &
344	( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
345
346	tend(k,j,i) = tend(k,j,i) &
347	& + ( kmzp * ( ( v(k+1,j,i) - v(k,j,i) ) * ddzu(k+1)&
348	& + ( w(k,j,i) - w(k,j-1,i) ) * ddy &
349	& ) &
350	& - kmzm * ( ( v(k,j,i) - v(k-1,j,i) ) * ddzu(k)&
351	& + ( w(k-1,j,i) - w(k-1,j-1,i) ) * ddy &
352	& ) &
353	& ) * ddzw(k)
354	ENDIF
355	ENDDO
356
357	ENDDO
358	ENDDO
359
360	!
361	!-- Vertical diffusion at the first grid point above the surface,
362	!-- if the momentum flux at the bottom is given by the Prandtl law
363	!-- or if it is prescribed by the user.
364	!-- Difference quotient of the momentum flux is not formed over
365	!-- half of the grid spacing (2.0*ddzw(k)) any more, since the
366	!-- comparison with other (LES) modell showed that the values of
367	!-- the momentum flux becomes too large in this case.
368	!-- The term containing w(k-1,..) (see above equation) is removed here
369	!-- because the vertical velocity is assumed to be zero at the surface.
370	IF ( use_surface_fluxes ) THEN
371
372	DO i = i_left, i_right
373	DO j = j_south, j_north
374
375	k = nzb_v_inner(j,i)+1
376	!
377	!-- Interpolate eddy diffusivities on staggered gridpoints
378	kmzp = 0.25 * &
379	( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
380	kmzm = 0.25 * &
381	( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
382
383	tend(k,j,i) = tend(k,j,i) &
384	& + ( kmzp * ( w(k,j,i) - w(k,j-1,i) ) * ddy &
385	& ) * ddzw(k) &
386	& + ( kmzp * ( v(k+1,j,i) - v(k,j,i) ) * ddzu(k+1) &
387	& + vsws(j,i) &
388	& ) * ddzw(k)
389	ENDDO
390	ENDDO
391
392	ENDIF
393
394	!
395	!-- Vertical diffusion at the first gridpoint below the top boundary,
396	!-- if the momentum flux at the top is prescribed by the user
397	IF ( use_top_fluxes .AND. constant_top_momentumflux ) THEN
398
399	k = nzt
400
401	DO i = i_left, i_right
402	DO j = j_south, j_north
403
404	!
405	!-- Interpolate eddy diffusivities on staggered gridpoints
406	kmzp = 0.25 * &
407	( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
408	kmzm = 0.25 * &
409	( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
410
411	tend(k,j,i) = tend(k,j,i) &
412	& - ( kmzm * ( w(k-1,j,i) - w(k-1,j-1,i) ) * ddy &
413	& ) * ddzw(k) &
414	& + ( -vswst(j,i) &
415	& - kmzm * ( v(k,j,i) - v(k-1,j,i) ) * ddzu(k) &
416	& ) * ddzw(k)
417	ENDDO
418	ENDDO
419
420	ENDIF
421	!$acc end kernels
422
423	END SUBROUTINE diffusion_v_acc
424
425
426	!------------------------------------------------------------------------------!
427	! Call for grid point i,j
428	!------------------------------------------------------------------------------!
429	SUBROUTINE diffusion_v_ij( i, j )
430
431	USE arrays_3d
432	USE control_parameters
433	USE grid_variables
434	USE indices
435
436	IMPLICIT NONE
437
438	INTEGER :: i, j, k
439	REAL :: kmxm, kmxp, kmzm, kmzp
440
441	REAL, DIMENSION(nzb:nzt+1) :: vsus
442
443	!
444	!-- Compute horizontal diffusion
445	DO k = nzb_v_outer(j,i)+1, nzt
446	!
447	!-- Interpolate eddy diffusivities on staggered gridpoints
448	kmxp = 0.25 * ( km(k,j,i)+km(k,j,i+1)+km(k,j-1,i)+km(k,j-1,i+1) )
449	kmxm = 0.25 * ( km(k,j,i)+km(k,j,i-1)+km(k,j-1,i)+km(k,j-1,i-1) )
450
451	tend(k,j,i) = tend(k,j,i) &
452	& + ( kmxp * ( v(k,j,i+1) - v(k,j,i) ) * ddx &
453	& + kmxp * ( u(k,j,i+1) - u(k,j-1,i+1) ) * ddy &
454	& - kmxm * ( v(k,j,i) - v(k,j,i-1) ) * ddx &
455	& - kmxm * ( u(k,j,i) - u(k,j-1,i) ) * ddy &
456	& ) * ddx &
457	& + 2.0 * ( &
458	& km(k,j,i) * ( v(k,j+1,i) - v(k,j,i) ) &
459	& - km(k,j-1,i) * ( v(k,j,i) - v(k,j-1,i) ) &
460	& ) * ddy2
461	ENDDO
462
463	!
464	!-- Wall functions at the left and right walls, respectively
465	IF ( wall_v(j,i) /= 0.0 ) THEN
466
467	!
468	!-- Calculate the horizontal momentum flux v'u'
469	CALL wall_fluxes( i, j, nzb_v_inner(j,i)+1, nzb_v_outer(j,i), &
470	vsus, 0.0, 1.0, 0.0, 0.0 )
471
472	DO k = nzb_v_inner(j,i)+1, nzb_v_outer(j,i)
473	kmxp = 0.25 * &
474	( km(k,j,i)+km(k,j,i+1)+km(k,j-1,i)+km(k,j-1,i+1) )
475	kmxm = 0.25 * &
476	( km(k,j,i)+km(k,j,i-1)+km(k,j-1,i)+km(k,j-1,i-1) )
477
478	tend(k,j,i) = tend(k,j,i) &
479	+ 2.0 * ( &
480	km(k,j,i) * ( v(k,j+1,i) - v(k,j,i) ) &
481	- km(k,j-1,i) * ( v(k,j,i) - v(k,j-1,i) ) &
482	) * ddy2 &
483	+ ( fxp(j,i) * ( &
484	kmxp * ( v(k,j,i+1) - v(k,j,i) ) * ddx &
485	+ kmxp * ( u(k,j,i+1) - u(k,j-1,i+1) ) * ddy &
486	) &
487	- fxm(j,i) * ( &
488	kmxm * ( v(k,j,i) - v(k,j,i-1) ) * ddx &
489	+ kmxm * ( u(k,j,i) - u(k,j-1,i) ) * ddy &
490	) &
491	+ wall_v(j,i) * vsus(k) &
492	) * ddx
493	ENDDO
494	ENDIF
495
496	!
497	!-- Compute vertical diffusion. In case of simulating a Prandtl layer,
498	!-- index k starts at nzb_v_inner+2.
499	DO k = nzb_diff_v(j,i), nzt_diff
500	!
501	!-- Interpolate eddy diffusivities on staggered gridpoints
502	kmzp = 0.25 * ( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
503	kmzm = 0.25 * ( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
504
505	tend(k,j,i) = tend(k,j,i) &
506	& + ( kmzp * ( ( v(k+1,j,i) - v(k,j,i) ) * ddzu(k+1) &
507	& + ( w(k,j,i) - w(k,j-1,i) ) * ddy &
508	& ) &
509	& - kmzm * ( ( v(k,j,i) - v(k-1,j,i) ) * ddzu(k) &
510	& + ( w(k-1,j,i) - w(k-1,j-1,i) ) * ddy &
511	& ) &
512	& ) * ddzw(k)
513	ENDDO
514
515	!
516	!-- Vertical diffusion at the first grid point above the surface, if the
517	!-- momentum flux at the bottom is given by the Prandtl law or if it is
518	!-- prescribed by the user.
519	!-- Difference quotient of the momentum flux is not formed over half of
520	!-- the grid spacing (2.0*ddzw(k)) any more, since the comparison with
521	!-- other (LES) modell showed that the values of the momentum flux becomes
522	!-- too large in this case.
523	!-- The term containing w(k-1,..) (see above equation) is removed here
524	!-- because the vertical velocity is assumed to be zero at the surface.
525	IF ( use_surface_fluxes ) THEN
526	k = nzb_v_inner(j,i)+1
527	!
528	!-- Interpolate eddy diffusivities on staggered gridpoints
529	kmzp = 0.25 * ( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
530	kmzm = 0.25 * ( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
531
532	tend(k,j,i) = tend(k,j,i) &
533	& + ( kmzp * ( w(k,j,i) - w(k,j-1,i) ) * ddy &
534	& ) * ddzw(k) &
535	& + ( kmzp * ( v(k+1,j,i) - v(k,j,i) ) * ddzu(k+1) &
536	& + vsws(j,i) &
537	& ) * ddzw(k)
538	ENDIF
539
540	!
541	!-- Vertical diffusion at the first gridpoint below the top boundary,
542	!-- if the momentum flux at the top is prescribed by the user
543	IF ( use_top_fluxes .AND. constant_top_momentumflux ) THEN
544	k = nzt
545	!
546	!-- Interpolate eddy diffusivities on staggered gridpoints
547	kmzp = 0.25 * &
548	( km(k,j,i)+km(k+1,j,i)+km(k,j-1,i)+km(k+1,j-1,i) )
549	kmzm = 0.25 * &
550	( km(k,j,i)+km(k-1,j,i)+km(k,j-1,i)+km(k-1,j-1,i) )
551
552	tend(k,j,i) = tend(k,j,i) &
553	& - ( kmzm * ( w(k-1,j,i) - w(k-1,j-1,i) ) * ddy &
554	& ) * ddzw(k) &
555	& + ( -vswst(j,i) &
556	& - kmzm * ( v(k,j,i) - v(k-1,j,i) ) * ddzu(k) &
557	& ) * ddzw(k)
558	ENDIF
559
560	END SUBROUTINE diffusion_v_ij
561
562	END MODULE diffusion_v_mod

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source: palm/trunk/SOURCE/diffusion_v.f90 @ 1257

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