source: palm/trunk/SOURCE/diffusivities.f90 @ 1037

Last change on this file since 1037 was 1037, checked in by raasch, 9 years ago

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1 SUBROUTINE diffusivities( var, var_reference )
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!
23!
24! Former revisions:
25! -----------------
26! $Id: diffusivities.f90 1037 2012-10-22 14:10:22Z raasch $
27!
28! 1036 2012-10-22 13:43:42Z raasch
29! code put under GPL (PALM 3.9)
30!
31! 1015 2012-09-27 09:23:24Z raasch
32! OpenACC statements added + code changes required for GPU optimization,
33! adjustment of mixing length to the Prandtl mixing length at first grid point
34! above ground removed
35!
36! 667 2010-12-23 12:06:00Z suehring/gryschka
37! nxl-1, nxr+1, nys-1, nyn+1 replaced by nxlg, nxrg, nysg, nyng
38!
39! 137 2007-11-28 08:50:10Z letzel
40! Bugfix for summation of sums_l_l for flow_statistics
41! Vertical scalar profiles now based on nzb_s_inner and ngp_2dh_s_inner.
42!
43! 97 2007-06-21 08:23:15Z raasch
44! Adjustment of mixing length calculation for the ocean version.
45! This is also a bugfix, because the height above the topography is now
46! used instead of the height above level k=0.
47! theta renamed var, dpt_dz renamed dvar_dz, +new argument var_reference
48! use_pt_reference renamed use_reference
49!
50! 57 2007-03-09 12:05:41Z raasch
51! Reference temperature pt_reference can be used in buoyancy term
52!
53! RCS Log replace by Id keyword, revision history cleaned up
54!
55! Revision 1.24  2006/04/26 12:16:26  raasch
56! OpenMP optimization (+sums_l_l_t), sqrt_e must be private
57!
58! Revision 1.1  1997/09/19 07:41:10  raasch
59! Initial revision
60!
61!
62! Description:
63! ------------
64! Computation of the turbulent diffusion coefficients for momentum and heat
65! according to Prandtl-Kolmogorov
66!------------------------------------------------------------------------------!
67
68    USE arrays_3d
69    USE control_parameters
70    USE grid_variables
71    USE indices
72    USE pegrid
73    USE statistics
74
75    IMPLICIT NONE
76
77    INTEGER ::  i, j, k, omp_get_thread_num, sr, tn
78
79    REAL    ::  dvar_dz, l, ll, l_stable, sqrt_e, var_reference
80
81    REAL    ::  var(nzb:nzt+1,nysg:nyng,nxlg:nxrg)
82
83
84!
85!-- Default thread number in case of one thread
86    tn = 0
87
88!
89!-- Initialization for calculation of the mixing length profile
90    sums_l_l = 0.0
91
92!
93!-- Compute the turbulent diffusion coefficient for momentum
94    !$OMP PARALLEL PRIVATE (dvar_dz,i,j,k,l,ll,l_stable,sqrt_e,sr,tn)
95!$  tn = omp_get_thread_num()
96
97!
98!-- Data declerations for accelerators
99    !$acc data present( dd2zu, e, km, kh, l_grid, l_wall, nzb_s_inner, rif, var )
100    !$acc kernels
101
102!
103!-- Introduce an optional minimum tke
104    IF ( e_min > 0.0 )  THEN
105       !$OMP DO
106       !$acc loop
107       DO  i = nxlg, nxrg
108          DO  j = nysg, nyng
109             !$acc loop vector( 32 )
110             DO  k = 1, nzt
111                IF ( k > nzb_s_inner(j,i) )  THEN
112                   e(k,j,i) = MAX( e(k,j,i), e_min )
113                ENDIF
114             ENDDO
115          ENDDO
116       ENDDO
117    ENDIF
118
119    !$OMP DO
120    !$acc loop
121    DO  i = nxlg, nxrg
122       DO  j = nysg, nyng
123          !$acc loop vector( 32 )
124          DO  k = 1, nzt
125
126             IF ( k > nzb_s_inner(j,i) )  THEN
127
128                sqrt_e = SQRT( e(k,j,i) )
129!
130!--             Determine the mixing length
131                dvar_dz = atmos_ocean_sign * &  ! inverse effect of pt/rho gradient
132                          ( var(k+1,j,i) - var(k-1,j,i) ) * dd2zu(k)
133                IF ( dvar_dz > 0.0 ) THEN
134                   IF ( use_reference )  THEN
135                      l_stable = 0.76 * sqrt_e / &
136                                 SQRT( g / var_reference * dvar_dz ) + 1E-5
137                   ELSE
138                      l_stable = 0.76 * sqrt_e / &
139                                 SQRT( g / var(k,j,i) * dvar_dz ) + 1E-5
140                   ENDIF
141                ELSE
142                   l_stable = l_grid(k)
143                ENDIF
144!
145!--             Adjustment of the mixing length
146                IF ( wall_adjustment )  THEN
147                   = MIN( l_wall(k,j,i), l_grid(k), l_stable )
148                   ll = MIN( l_wall(k,j,i), l_grid(k) )
149                ELSE
150                   = MIN( l_grid(k), l_stable )
151                   ll = l_grid(k)
152                ENDIF
153
154      !
155      !--       Compute diffusion coefficients for momentum and heat
156                km(k,j,i) = 0.1 * l * sqrt_e
157                kh(k,j,i) = ( 1.0 + 2.0 * l / ll ) * km(k,j,i)
158
159             ENDIF
160
161#if ! defined( __openacc )
162!
163!++          Statistics still have to be realized for accelerators
164!--          Summation for averaged profile (cf. flow_statistics)
165             DO  sr = 0, statistic_regions
166                sums_l_l(k,sr,tn) = sums_l_l(k,sr,tn) + l * rmask(j,i,sr)
167             ENDDO
168#endif
169
170          ENDDO
171       ENDDO
172    ENDDO
173
174#if ! defined( __openacc )
175!
176!++ Statistics still have to be realized for accelerators
177    sums_l_l(nzt+1,:,tn) = sums_l_l(nzt,:,tn)   ! quasi boundary-condition for
178                                                  ! data output
179#endif
180    !$OMP END PARALLEL
181
182!
183!-- Set vertical boundary values (Neumann conditions both at bottom and top).
184!-- Horizontal boundary conditions at vertical walls are not set because
185!-- so far vertical walls require usage of a Prandtl-layer where the boundary
186!-- values of the diffusivities are not needed
187    !$OMP PARALLEL DO
188    !$acc loop
189    DO  i = nxlg, nxrg
190       DO  j = nysg, nyng
191          km(nzb_s_inner(j,i),j,i) = km(nzb_s_inner(j,i)+1,j,i)
192          km(nzt+1,j,i)            = km(nzt,j,i)
193          kh(nzb_s_inner(j,i),j,i) = kh(nzb_s_inner(j,i)+1,j,i)
194          kh(nzt+1,j,i)            = kh(nzt,j,i)
195       ENDDO
196    ENDDO
197
198!
199!-- Set Neumann boundary conditions at the outflow boundaries in case of
200!-- non-cyclic lateral boundaries
201    IF ( outflow_l )  THEN
202       km(:,:,nxl-1) = km(:,:,nxl)
203       kh(:,:,nxl-1) = kh(:,:,nxl)
204    ENDIF
205    IF ( outflow_r )  THEN
206       km(:,:,nxr+1) = km(:,:,nxr)
207       kh(:,:,nxr+1) = kh(:,:,nxr)
208    ENDIF
209    IF ( outflow_s )  THEN
210       km(:,nys-1,:) = km(:,nys,:)
211       kh(:,nys-1,:) = kh(:,nys,:)
212    ENDIF
213    IF ( outflow_n )  THEN
214       km(:,nyn+1,:) = km(:,nyn,:)
215       kh(:,nyn+1,:) = kh(:,nyn,:)
216    ENDIF
217
218    !$acc end kernels
219    !$acc end data
220
221 END SUBROUTINE diffusivities
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