source: palm/trunk/SOURCE/disturb_field.f90 @ 2696

Last change on this file since 2696 was 2696, checked in by kanani, 4 years ago

Merge of branch palm4u into trunk

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1!> @file disturb_field.f90
2!------------------------------------------------------------------------------!
3! This file is part of the PALM model system.
4!
5! PALM is free software: you can redistribute it and/or modify it under the
6! terms of the GNU General Public License as published by the Free Software
7! Foundation, either version 3 of the License, or (at your option) any later
8! 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 1997-2017 Leibniz Universitaet Hannover
18!------------------------------------------------------------------------------!
19!
20! Current revisions:
21! ------------------
22!
23!
24! Former revisions:
25! -----------------
26! $Id: disturb_field.f90 2696 2017-12-14 17:12:51Z kanani $
27! NEC related code removed
28!
29! 2233 2017-05-30 18:08:54Z suehring
30!
31! 2232 2017-05-30 17:47:52Z suehring
32! Modify referenced parameter for disturb_field, instead of nzb_uv_inner, pass
33! character to identify the respective grid (u- or v-grid).
34! Set perturbations within topography to zero using flags.
35!
36! 2172 2017-03-08 15:55:25Z knoop
37! Bugfix removed id_random_array from USE list
38!
39! 2000 2016-08-20 18:09:15Z knoop
40! Forced header and separation lines into 80 columns
41!
42! 1682 2015-10-07 23:56:08Z knoop
43! Code annotations made doxygen readable
44!
45! 1425 2014-07-05 10:57:53Z knoop
46! bugfix: Parallel random number generator loop: print-statement no needed
47!
48! 1400 2014-05-09 14:03:54Z knoop
49! Parallel random number generator added
50!
51! 1353 2014-04-08 15:21:23Z heinze
52! REAL constants provided with KIND-attribute
53!
54! 1322 2014-03-20 16:38:49Z raasch
55! REAL constants defined as wp-kind
56!
57! 1320 2014-03-20 08:40:49Z raasch
58! ONLY-attribute added to USE-statements,
59! kind-parameters added to all INTEGER and REAL declaration statements,
60! kinds are defined in new module kinds,
61! revision history before 2012 removed,
62! comment fields (!:) to be used for variable explanations added to
63! all variable declaration statements
64!
65! 1036 2012-10-22 13:43:42Z raasch
66! code put under GPL (PALM 3.9)
67!
68! Revision 1.1  1998/02/04 15:40:45  raasch
69! Initial revision
70!
71!
72! Description:
73! ------------
74!> Imposing a random perturbation on a 3D-array.
75!> On parallel computers, the random number generator is as well called for all
76!> gridpoints of the total domain to ensure, regardless of the number of PEs
77!> used, that the elements of the array have the same values in the same
78!> order in every case. The perturbation range is steered by dist_range.
79!------------------------------------------------------------------------------!
80 SUBROUTINE disturb_field( var_char, dist1, field )
81 
82
83    USE control_parameters,                                                    &
84        ONLY:  dist_nxl, dist_nxr, dist_nyn, dist_nys, dist_range,             &
85               disturbance_amplitude, disturbance_created,                     &
86               disturbance_level_ind_b, disturbance_level_ind_t, iran,         &
87               random_generator, topography
88               
89    USE cpulog,                                                                &
90        ONLY:  cpu_log, log_point
91       
92    USE indices,                                                               &
93        ONLY:  nbgp, nxl, nxlg, nxr, nxrg, nyn, nyng, nys, nysg, nzb, nzb_max, &
94               nzt, wall_flags_0
95       
96    USE kinds
97   
98    USE random_function_mod,                                                   &
99        ONLY: random_function
100       
101    USE random_generator_parallel,                                             &
102        ONLY:  random_number_parallel, random_seed_parallel, random_dummy,     &
103               seq_random_array
104
105    IMPLICIT NONE
106
107    CHARACTER (LEN = *) ::  var_char !< flag to distinguish betwenn u- and v-component
108
109    INTEGER(iwp) ::  flag_nr !< number of respective flag for u- or v-grid
110    INTEGER(iwp) ::  i       !< index variable
111    INTEGER(iwp) ::  j       !< index variable
112    INTEGER(iwp) ::  k       !< index variable
113
114    REAL(wp) ::  randomnumber  !<
115   
116    REAL(wp) ::  dist1(nzb:nzt+1,nysg:nyng,nxlg:nxrg)  !<
117    REAL(wp) ::  field(nzb:nzt+1,nysg:nyng,nxlg:nxrg)  !<
118   
119    REAL(wp), DIMENSION(:,:,:), ALLOCATABLE ::  dist2  !<
120
121
122    CALL cpu_log( log_point(20), 'disturb_field', 'start' )
123!
124!-- Set flag number, 20 for u-grid, 21 for v-grid, required to mask topography
125    flag_nr = MERGE( 20, 21, TRIM(var_char) == 'u' )
126!
127!-- Create an additional temporary array and initialize the arrays needed
128!-- to store the disturbance
129    ALLOCATE( dist2(nzb:nzt+1,nysg:nyng,nxlg:nxrg) )
130    dist1 = 0.0_wp
131    dist2 = 0.0_wp
132
133!
134!-- Create the random perturbation and store it on temporary array
135    IF ( random_generator == 'numerical-recipes' )  THEN
136       DO  i = dist_nxl(dist_range), dist_nxr(dist_range)
137          DO  j = dist_nys(dist_range), dist_nyn(dist_range)
138             DO  k = disturbance_level_ind_b, disturbance_level_ind_t
139                randomnumber = 3.0_wp * disturbance_amplitude *                &
140                               ( random_function( iran ) - 0.5_wp )
141                IF ( nxl <= i  .AND.  nxr >= i  .AND.  nys <= j  .AND.         &
142                     nyn >= j )                                                &
143                THEN
144                   dist1(k,j,i) = randomnumber
145                ENDIF
146             ENDDO
147          ENDDO
148       ENDDO
149    ELSEIF ( random_generator == 'random-parallel' )  THEN
150       DO  i = dist_nxl(dist_range), dist_nxr(dist_range)
151          DO  j = dist_nys(dist_range), dist_nyn(dist_range)
152             CALL random_seed_parallel( put=seq_random_array(:, j, i) )
153             DO  k = disturbance_level_ind_b, disturbance_level_ind_t
154                CALL random_number_parallel( random_dummy )
155                randomnumber = 3.0_wp * disturbance_amplitude *                &
156                               ( random_dummy - 0.5_wp )
157                IF ( nxl <= i  .AND.  nxr >= i  .AND.  nys <= j  .AND.         &
158                     nyn >= j )                                                &
159                THEN
160                   dist1(k,j,i) = randomnumber
161                ENDIF
162             ENDDO
163             CALL random_seed_parallel( get=seq_random_array(:, j, i) )
164          ENDDO
165       ENDDO
166    ELSEIF ( random_generator == 'system-specific' )  THEN
167       DO  i = dist_nxl(dist_range), dist_nxr(dist_range)
168          DO  j = dist_nys(dist_range), dist_nyn(dist_range)
169             DO  k = disturbance_level_ind_b, disturbance_level_ind_t
170                CALL RANDOM_NUMBER( randomnumber )
171                randomnumber = 3.0_wp * disturbance_amplitude *                &
172                                ( randomnumber - 0.5_wp )
173                IF ( nxl <= i .AND. nxr >= i .AND. nys <= j .AND. nyn >= j )   &
174                THEN
175                   dist1(k,j,i) = randomnumber
176                ENDIF
177             ENDDO
178          ENDDO
179       ENDDO
180
181    ENDIF
182
183!
184!-- Exchange of ghost points for the random perturbation
185
186    CALL exchange_horiz( dist1, nbgp )
187!
188!-- Applying the Shuman filter in order to smooth the perturbations.
189!-- Neighboured grid points in all three directions are used for the
190!-- filter operation.
191!-- Loop has been splitted to make runs reproducible on HLRN systems using
192!-- compiler option -O3
193     DO  i = nxl, nxr
194        DO  j = nys, nyn
195          DO  k = disturbance_level_ind_b-1, disturbance_level_ind_t+1
196             dist2(k,j,i) = ( dist1(k,j,i-1) + dist1(k,j,i+1)                  &
197                            + dist1(k,j+1,i) + dist1(k+1,j,i)                  &
198                            ) / 12.0_wp
199          ENDDO
200          DO  k = disturbance_level_ind_b-1, disturbance_level_ind_t+1
201              dist2(k,j,i) = dist2(k,j,i) + ( dist1(k,j-1,i) + dist1(k-1,j,i)  &
202                            + 6.0_wp * dist1(k,j,i)                            &
203                            ) / 12.0_wp
204          ENDDO
205        ENDDO
206     ENDDO
207
208!
209!-- Exchange of ghost points for the filtered perturbation.
210!-- Afterwards, filter operation and exchange of ghost points are repeated.
211    CALL exchange_horiz( dist2, nbgp )
212
213    DO  i = nxl, nxr
214       DO  j = nys, nyn
215          DO  k = disturbance_level_ind_b-2, disturbance_level_ind_t+2
216             dist1(k,j,i) = ( dist2(k,j,i-1) + dist2(k,j,i+1) + dist2(k,j-1,i) &
217                            + dist2(k,j+1,i) + dist2(k+1,j,i) + dist2(k-1,j,i) &
218                            + 6.0_wp * dist2(k,j,i)                            &
219                            ) / 12.0_wp
220          ENDDO
221       ENDDO
222    ENDDO
223
224    CALL exchange_horiz( dist1, nbgp )
225
226!
227!-- Remove perturbations below topography (including one gridpoint above it
228!-- in order to allow for larger timesteps at the beginning of the simulation
229!-- (diffusion criterion))
230    IF ( TRIM( topography ) /= 'flat' )  THEN
231       DO  i = nxlg, nxrg
232          DO  j = nysg, nyng
233             DO  k = nzb, nzb_max
234                dist1(k,j,i) = MERGE( dist1(k,j,i), 0.0_wp,                    &
235                                      BTEST( wall_flags_0(k,j,i), flag_nr )    &
236                                    )
237             ENDDO
238          ENDDO
239       ENDDO
240    ENDIF
241
242!
243!-- Random perturbation is added to the array to be disturbed.
244    DO  i = nxlg, nxrg
245       DO  j = nysg, nyng
246          DO  k = disturbance_level_ind_b-2, disturbance_level_ind_t+2
247             field(k,j,i) = field(k,j,i) + dist1(k,j,i)
248          ENDDO
249       ENDDO
250    ENDDO
251
252!
253!-- Deallocate the temporary array
254    DEALLOCATE( dist2 )
255
256!
257!-- Set a flag, which indicates that a random perturbation is imposed
258    disturbance_created = .TRUE.
259
260
261    CALL cpu_log( log_point(20), 'disturb_field', 'stop' )
262
263
264 END SUBROUTINE disturb_field
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