source: palm/trunk/SOURCE/diffusivities.f90 @ 2101

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1!> @file diffusivities.f90
2!------------------------------------------------------------------------------!
3! This file is part of PALM.
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: diffusivities.f90 2101 2017-01-05 16:42:31Z suehring $
27!
28! 2031 2016-10-21 15:11:58Z knoop
29! renamed variable rho to rho_ocean
30!
31! 2000 2016-08-20 18:09:15Z knoop
32! Forced header and separation lines into 80 columns
33!
34! 1711 2015-11-05 07:38:04Z raasch
35! bugfix: loop moved into IF block to avoid usage of l without being defined
36!
37! 1682 2015-10-07 23:56:08Z knoop
38! Code annotations made doxygen readable
39!
40! 1374 2014-04-25 12:55:07Z raasch
41! rif removed from acc-present-list
42!
43! 1353 2014-04-08 15:21:23Z heinze
44! REAL constants provided with KIND-attribute
45!
46! 1340 2014-03-25 19:45:13Z kanani
47! REAL constants defined as wp-kind
48!
49! 1322 2014-03-20 16:38:49Z raasch
50! REAL constants defined as wp-kind
51!
52! 1320 2014-03-20 08:40:49Z raasch
53! ONLY-attribute added to USE-statements,
54! kind-parameters added to all INTEGER and REAL declaration statements,
55! kinds are defined in new module kinds,
56! revision history before 2012 removed,
57! comment fields (!:) to be used for variable explanations added to
58! all variable declaration statements
59!
60! 1179 2013-06-14 05:57:58Z raasch
61! use_reference renamed use_single_reference_value
62!
63! 1036 2012-10-22 13:43:42Z raasch
64! code put under GPL (PALM 3.9)
65!
66! 1015 2012-09-27 09:23:24Z raasch
67! OpenACC statements added + code changes required for GPU optimization,
68! adjustment of mixing length to the Prandtl mixing length at first grid point
69! above ground removed
70!
71! Revision 1.1  1997/09/19 07:41:10  raasch
72! Initial revision
73!
74!
75! Description:
76! ------------
77!> Computation of the turbulent diffusion coefficients for momentum and heat
78!> according to Prandtl-Kolmogorov
79!------------------------------------------------------------------------------!
80 SUBROUTINE diffusivities( var, var_reference )
81 
82
83    USE arrays_3d,                                                             &
84        ONLY:  dd2zu, e, kh, km, l_grid, l_wall
85       
86    USE control_parameters,                                                    &
87        ONLY:  atmos_ocean_sign, e_min, g, outflow_l, outflow_n, outflow_r,    &
88                outflow_s, use_single_reference_value, wall_adjustment
89               
90    USE indices,                                                               &
91        ONLY:  nxl, nxlg, nxr, nxrg, nyn, nyng, nys, nysg, nzb_s_inner, nzb, nzt
92    USE kinds
93   
94    USE pegrid
95   
96    USE statistics,                                                            &
97        ONLY :  rmask, statistic_regions, sums_l_l
98
99    IMPLICIT NONE
100
101    INTEGER(iwp) ::  i                   !<
102    INTEGER(iwp) ::  j                   !<
103    INTEGER(iwp) ::  k                   !<
104    INTEGER(iwp) ::  omp_get_thread_num  !<
105    INTEGER(iwp) ::  sr                  !<
106    INTEGER(iwp) ::  tn                  !<
107
108    REAL(wp)     ::  dvar_dz             !<
109    REAL(wp)     ::  l                   !<
110    REAL(wp)     ::  ll                  !<
111    REAL(wp)     ::  l_stable            !<
112    REAL(wp)     ::  sqrt_e              !<
113    REAL(wp)     ::  var_reference       !<
114
115    REAL(wp)     ::  var(nzb:nzt+1,nysg:nyng,nxlg:nxrg)  !<
116
117
118!
119!-- Default thread number in case of one thread
120    tn = 0
121
122!
123!-- Initialization for calculation of the mixing length profile
124    sums_l_l = 0.0_wp
125
126!
127!-- Compute the turbulent diffusion coefficient for momentum
128    !$OMP PARALLEL PRIVATE (dvar_dz,i,j,k,l,ll,l_stable,sqrt_e,sr,tn)
129!$  tn = omp_get_thread_num()
130
131!
132!-- Data declerations for accelerators
133    !$acc data present( dd2zu, e, km, kh, l_grid, l_wall, nzb_s_inner, var )
134    !$acc kernels
135
136!
137!-- Introduce an optional minimum tke
138    IF ( e_min > 0.0_wp )  THEN
139       !$OMP DO
140       !$acc loop
141       DO  i = nxlg, nxrg
142          DO  j = nysg, nyng
143             !$acc loop vector( 32 )
144             DO  k = 1, nzt
145                IF ( k > nzb_s_inner(j,i) )  THEN
146                   e(k,j,i) = MAX( e(k,j,i), e_min )
147                ENDIF
148             ENDDO
149          ENDDO
150       ENDDO
151    ENDIF
152
153    !$OMP DO
154    !$acc loop
155    DO  i = nxlg, nxrg
156       DO  j = nysg, nyng
157          !$acc loop vector( 32 )
158          DO  k = 1, nzt
159
160             IF ( k > nzb_s_inner(j,i) )  THEN
161
162                sqrt_e = SQRT( e(k,j,i) )
163!
164!--             Determine the mixing length
165                dvar_dz = atmos_ocean_sign * &  ! inverse effect of pt/rho_ocean gradient
166                          ( var(k+1,j,i) - var(k-1,j,i) ) * dd2zu(k)
167                IF ( dvar_dz > 0.0_wp ) THEN
168                   IF ( use_single_reference_value )  THEN
169                      l_stable = 0.76_wp * sqrt_e /                            &
170                                    SQRT( g / var_reference * dvar_dz ) + 1E-5_wp
171                   ELSE
172                      l_stable = 0.76_wp * sqrt_e /                            &
173                                    SQRT( g / var(k,j,i) * dvar_dz ) + 1E-5_wp
174                   ENDIF
175                ELSE
176                   l_stable = l_grid(k)
177                ENDIF
178!
179!--             Adjustment of the mixing length
180                IF ( wall_adjustment )  THEN
181                   = MIN( l_wall(k,j,i), l_grid(k), l_stable )
182                   ll = MIN( l_wall(k,j,i), l_grid(k) )
183                ELSE
184                   = MIN( l_grid(k), l_stable )
185                   ll = l_grid(k)
186                ENDIF
187
188      !
189      !--       Compute diffusion coefficients for momentum and heat
190                km(k,j,i) = 0.1_wp * l * sqrt_e
191                kh(k,j,i) = ( 1.0_wp + 2.0_wp * l / ll ) * km(k,j,i)
192
193#if ! defined( __openacc )
194!
195!++             Statistics still have to be realized for accelerators
196!--             Summation for averaged profile (cf. flow_statistics)
197                DO  sr = 0, statistic_regions
198                   sums_l_l(k,sr,tn) = sums_l_l(k,sr,tn) + l * rmask(j,i,sr)
199                ENDDO
200#endif
201             ENDIF
202
203          ENDDO
204       ENDDO
205    ENDDO
206
207#if ! defined( __openacc )
208!
209!++ Statistics still have to be realized for accelerators
210    sums_l_l(nzt+1,:,tn) = sums_l_l(nzt,:,tn)   ! quasi boundary-condition for
211                                                  ! data output
212#endif
213    !$OMP END PARALLEL
214
215!
216!-- Set vertical boundary values (Neumann conditions both at bottom and top).
217!-- Horizontal boundary conditions at vertical walls are not set because
218!-- so far vertical walls require usage of a Prandtl-layer where the boundary
219!-- values of the diffusivities are not needed
220    !$OMP PARALLEL DO
221    !$acc loop
222    DO  i = nxlg, nxrg
223       DO  j = nysg, nyng
224          km(nzb_s_inner(j,i),j,i) = km(nzb_s_inner(j,i)+1,j,i)
225          km(nzt+1,j,i)            = km(nzt,j,i)
226          kh(nzb_s_inner(j,i),j,i) = kh(nzb_s_inner(j,i)+1,j,i)
227          kh(nzt+1,j,i)            = kh(nzt,j,i)
228       ENDDO
229    ENDDO
230
231!
232!-- Set Neumann boundary conditions at the outflow boundaries in case of
233!-- non-cyclic lateral boundaries
234    IF ( outflow_l )  THEN
235       km(:,:,nxl-1) = km(:,:,nxl)
236       kh(:,:,nxl-1) = kh(:,:,nxl)
237    ENDIF
238    IF ( outflow_r )  THEN
239       km(:,:,nxr+1) = km(:,:,nxr)
240       kh(:,:,nxr+1) = kh(:,:,nxr)
241    ENDIF
242    IF ( outflow_s )  THEN
243       km(:,nys-1,:) = km(:,nys,:)
244       kh(:,nys-1,:) = kh(:,nys,:)
245    ENDIF
246    IF ( outflow_n )  THEN
247       km(:,nyn+1,:) = km(:,nyn,:)
248       kh(:,nyn+1,:) = kh(:,nyn,:)
249    ENDIF
250
251    !$acc end kernels
252    !$acc end data
253
254 END SUBROUTINE diffusivities
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