!> @file pres.f90 !------------------------------------------------------------------------------! ! This file is part of the PALM model system. ! ! PALM is free software: you can redistribute it and/or modify it under the ! terms of the GNU General Public License as published by the Free Software ! Foundation, either version 3 of the License, or (at your option) any later ! version. ! ! PALM is distributed in the hope that it will be useful, but WITHOUT ANY ! WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR ! A PARTICULAR PURPOSE. See the GNU General Public License for more details. ! ! You should have received a copy of the GNU General Public License along with ! PALM. If not, see . ! ! Copyright 1997-2019 Leibniz Universitaet Hannover !------------------------------------------------------------------------------! ! ! Current revisions: ! ------------------ ! ! ! Former revisions: ! ----------------- ! $Id: pres.f90 4182 2019-08-22 15:20:23Z suehring $ ! Corrected "Former revisions" section ! ! 4015 2019-06-05 13:25:35Z raasch ! variable child_domain_nvn eliminated ! ! 3849 2019-04-01 16:35:16Z knoop ! OpenACC port for SPEC ! ! Revision 1.1 1997/07/24 11:24:44 raasch ! Initial revision ! ! ! Description: ! ------------ !> Compute the divergence of the provisional velocity field. Solve the Poisson !> equation for the perturbation pressure. Compute the final velocities using !> this perturbation pressure. Compute the remaining divergence. !------------------------------------------------------------------------------! SUBROUTINE pres USE arrays_3d, & ONLY: d, ddzu, ddzu_pres, ddzw, dzw, p, p_loc, rho_air, rho_air_zw, & tend, u, v, w USE control_parameters, & ONLY: bc_lr_cyc, bc_ns_cyc, bc_radiation_l, bc_radiation_n, & bc_radiation_r, bc_radiation_s, child_domain, & conserve_volume_flow, coupling_mode, & dt_3d, gathered_size, ibc_p_b, ibc_p_t, & intermediate_timestep_count, intermediate_timestep_count_max, & mg_switch_to_pe0_level, nesting_offline, & psolver, subdomain_size, & topography, volume_flow, volume_flow_area, volume_flow_initial USE cpulog, & ONLY: cpu_log, log_point, log_point_s USE grid_variables, & ONLY: ddx, ddy USE indices, & ONLY: nbgp, ngp_2dh_outer, nx, nxl, nxlg, nxl_mg, nxr, nxrg, nxr_mg, & ny, nys, nysg, nys_mg, nyn, nyng, nyn_mg, nzb, nzt, nzt_mg, & wall_flags_0 USE kinds USE pegrid USE pmc_interface, & ONLY: nesting_mode USE poisfft_mod, & ONLY: poisfft USE poismg_mod USE poismg_noopt_mod USE statistics, & ONLY: statistic_regions, sums_divnew_l, sums_divold_l, weight_pres, & weight_substep USE surface_mod, & ONLY : bc_h IMPLICIT NONE INTEGER(iwp) :: i !< INTEGER(iwp) :: j !< INTEGER(iwp) :: k !< INTEGER(iwp) :: m !< REAL(wp) :: ddt_3d !< REAL(wp) :: d_weight_pres !< REAL(wp) :: localsum !< REAL(wp) :: threadsum !< REAL(wp) :: weight_pres_l !< REAL(wp) :: weight_substep_l !< REAL(wp), DIMENSION(1:3) :: volume_flow_l !< REAL(wp), DIMENSION(1:3) :: volume_flow_offset !< REAL(wp), DIMENSION(1:nzt) :: w_l !< REAL(wp), DIMENSION(1:nzt) :: w_l_l !< CALL cpu_log( log_point(8), 'pres', 'start' ) ! !-- Calculate quantities to be used locally ddt_3d = 1.0_wp / dt_3d IF ( intermediate_timestep_count == 0 ) THEN ! !-- If pres is called before initial time step weight_pres_l = 1.0_wp d_weight_pres = 1.0_wp weight_substep_l = 1.0_wp ELSE weight_pres_l = weight_pres(intermediate_timestep_count) d_weight_pres = 1.0_wp / weight_pres(intermediate_timestep_count) weight_substep_l = weight_substep(intermediate_timestep_count) ENDIF ! !-- Multigrid method expects array d to have one ghost layer. !-- IF ( psolver(1:9) == 'multigrid' ) THEN DEALLOCATE( d ) ALLOCATE( d(nzb:nzt+1,nys-1:nyn+1,nxl-1:nxr+1) ) ! !-- Since p is later used to hold the weighted average of the substeps, it !-- cannot be used in the iterative solver. Therefore, its initial value is !-- stored on p_loc, which is then iteratively advanced in every substep. IF ( intermediate_timestep_count <= 1 ) THEN DO i = nxl-1, nxr+1 DO j = nys-1, nyn+1 DO k = nzb, nzt+1 p_loc(k,j,i) = p(k,j,i) ENDDO ENDDO ENDDO ENDIF ELSEIF ( psolver == 'sor' .AND. intermediate_timestep_count <= 1 ) THEN ! !-- Since p is later used to hold the weighted average of the substeps, it !-- cannot be used in the iterative solver. Therefore, its initial value is !-- stored on p_loc, which is then iteratively advanced in every substep. p_loc = p ENDIF ! !-- Conserve the volume flow at the outflow in case of non-cyclic lateral !-- boundary conditions !-- WARNING: so far, this conservation does not work at the left/south !-- boundary if the topography at the inflow differs from that at the !-- outflow! For this case, volume_flow_area needs adjustment! ! !-- Left/right IF ( conserve_volume_flow .AND. ( bc_radiation_l .OR. & bc_radiation_r ) ) THEN volume_flow(1) = 0.0_wp volume_flow_l(1) = 0.0_wp IF ( bc_radiation_l ) THEN i = 0 ELSEIF ( bc_radiation_r ) THEN i = nx+1 ENDIF DO j = nys, nyn ! !-- Sum up the volume flow through the south/north boundary DO k = nzb+1, nzt volume_flow_l(1) = volume_flow_l(1) + u(k,j,i) * dzw(k) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 1 ) & ) ENDDO ENDDO #if defined( __parallel ) IF ( collective_wait ) CALL MPI_BARRIER( comm1dy, ierr ) CALL MPI_ALLREDUCE( volume_flow_l(1), volume_flow(1), 1, MPI_REAL, & MPI_SUM, comm1dy, ierr ) #else volume_flow = volume_flow_l #endif volume_flow_offset(1) = ( volume_flow_initial(1) - volume_flow(1) ) & / volume_flow_area(1) DO j = nysg, nyng DO k = nzb+1, nzt u(k,j,i) = u(k,j,i) + volume_flow_offset(1) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 1 ) & ) ENDDO ENDDO ENDIF ! !-- South/north IF ( conserve_volume_flow .AND. ( bc_radiation_n .OR. bc_radiation_s ) ) THEN volume_flow(2) = 0.0_wp volume_flow_l(2) = 0.0_wp IF ( bc_radiation_s ) THEN j = 0 ELSEIF ( bc_radiation_n ) THEN j = ny+1 ENDIF DO i = nxl, nxr ! !-- Sum up the volume flow through the south/north boundary DO k = nzb+1, nzt volume_flow_l(2) = volume_flow_l(2) + v(k,j,i) * dzw(k) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 2 ) & ) ENDDO ENDDO #if defined( __parallel ) IF ( collective_wait ) CALL MPI_BARRIER( comm1dx, ierr ) CALL MPI_ALLREDUCE( volume_flow_l(2), volume_flow(2), 1, MPI_REAL, & MPI_SUM, comm1dx, ierr ) #else volume_flow = volume_flow_l #endif volume_flow_offset(2) = ( volume_flow_initial(2) - volume_flow(2) ) & / volume_flow_area(2) DO i = nxlg, nxrg DO k = nzb+1, nzt v(k,j,i) = v(k,j,i) + volume_flow_offset(2) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 2 ) & ) ENDDO ENDDO ENDIF ! !-- Remove mean vertical velocity in case that Neumann conditions are used both at bottom and top !-- boundary. With Neumann conditions at both vertical boundaries, the solver cannot remove !-- mean vertical velocities. They should be removed, because incompressibility requires that !-- the vertical gradient of vertical velocity is zero. Since w=0 at the solid surface, it must be !-- zero everywhere. !-- This must not be done in case of a 3d-nesting child domain, because a mean vertical velocity !-- can physically exist in such a domain. !-- Also in case of offline nesting, mean vertical velocities may exist (and must not be removed), !-- caused by horizontal divergence/convergence of the large scale flow that is prescribed at the !-- side boundaries. !-- The removal cannot be done before the first initial time step because ngp_2dh_outer !-- is not yet known then. IF ( ibc_p_b == 1 .AND. ibc_p_t == 1 .AND. .NOT. nesting_offline & .AND. .NOT. ( child_domain .AND. nesting_mode /= 'vertical' ) & .AND. intermediate_timestep_count /= 0 ) & THEN w_l = 0.0_wp; w_l_l = 0.0_wp DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt w_l_l(k) = w_l_l(k) + w(k,j,i) & * MERGE( 1.0_wp, 0.0_wp, BTEST( wall_flags_0(k,j,i), 3 ) ) ENDDO ENDDO ENDDO #if defined( __parallel ) IF ( collective_wait ) CALL MPI_BARRIER( comm2d, ierr ) CALL MPI_ALLREDUCE( w_l_l(1), w_l(1), nzt, MPI_REAL, MPI_SUM, comm2d, ierr ) #else w_l = w_l_l #endif DO k = 1, nzt w_l(k) = w_l(k) / ngp_2dh_outer(k,0) ENDDO DO i = nxlg, nxrg DO j = nysg, nyng DO k = nzb+1, nzt w(k,j,i) = w(k,j,i) - w_l(k) & * MERGE( 1.0_wp, 0.0_wp, BTEST( wall_flags_0(k,j,i), 3 ) ) ENDDO ENDDO ENDDO ENDIF ! !-- Compute the divergence of the provisional velocity field. CALL cpu_log( log_point_s(1), 'divergence', 'start' ) IF ( psolver(1:9) == 'multigrid' ) THEN !$OMP PARALLEL DO SCHEDULE( STATIC ) PRIVATE (i,j,k) DO i = nxl-1, nxr+1 DO j = nys-1, nyn+1 DO k = nzb, nzt+1 d(k,j,i) = 0.0_wp ENDDO ENDDO ENDDO ELSE !$OMP PARALLEL DO SCHEDULE( STATIC ) PRIVATE (i,j,k) !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) & !$ACC PRESENT(d) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt d(k,j,i) = 0.0_wp ENDDO ENDDO ENDDO ENDIF localsum = 0.0_wp threadsum = 0.0_wp #if defined( __ibm ) !$OMP PARALLEL PRIVATE (i,j,k) FIRSTPRIVATE(threadsum) REDUCTION(+:localsum) !$OMP DO SCHEDULE( STATIC ) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt d(k,j,i) = ( ( u(k,j,i+1) - u(k,j,i) ) * rho_air(k) * ddx + & ( v(k,j+1,i) - v(k,j,i) ) * rho_air(k) * ddy + & ( w(k,j,i) * rho_air_zw(k) - & w(k-1,j,i) * rho_air_zw(k-1) ) * ddzw(k) & ) * ddt_3d * d_weight_pres & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 0 ) & ) ENDDO ! !-- Compute possible PE-sum of divergences for flow_statistics DO k = nzb+1, nzt threadsum = threadsum + ABS( d(k,j,i) ) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 0 ) & ) ENDDO ENDDO ENDDO IF ( intermediate_timestep_count == intermediate_timestep_count_max .OR. & intermediate_timestep_count == 0 ) THEN localsum = localsum + threadsum * dt_3d * weight_pres_l ENDIF !$OMP END PARALLEL #else !$OMP PARALLEL PRIVATE (i,j,k) !$OMP DO SCHEDULE( STATIC ) !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) & !$ACC PRESENT(u, v, w, rho_air, rho_air_zw, ddzw, wall_flags_0) & !$ACC PRESENT(d) DO i = nxl, nxr DO j = nys, nyn DO k = 1, nzt d(k,j,i) = ( ( u(k,j,i+1) - u(k,j,i) ) * rho_air(k) * ddx + & ( v(k,j+1,i) - v(k,j,i) ) * rho_air(k) * ddy + & ( w(k,j,i) * rho_air_zw(k) - & w(k-1,j,i) * rho_air_zw(k-1) ) * ddzw(k) & ) * ddt_3d * d_weight_pres & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 0 ) & ) ENDDO ENDDO ENDDO !$OMP END PARALLEL ! !-- Compute possible PE-sum of divergences for flow_statistics. Carry out !-- computation only at last Runge-Kutta substep. IF ( intermediate_timestep_count == intermediate_timestep_count_max .OR. & intermediate_timestep_count == 0 ) THEN !$OMP PARALLEL PRIVATE (i,j,k) FIRSTPRIVATE(threadsum) REDUCTION(+:localsum) !$OMP DO SCHEDULE( STATIC ) !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i,j,k) & !$ACC REDUCTION(+:threadsum) COPY(threadsum) & !$ACC PRESENT(d) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt threadsum = threadsum + ABS( d(k,j,i) ) ENDDO ENDDO ENDDO localsum = localsum + threadsum * dt_3d * weight_pres_l !$OMP END PARALLEL ENDIF #endif ! !-- For completeness, set the divergence sum of all statistic regions to those !-- of the total domain IF ( intermediate_timestep_count == intermediate_timestep_count_max .OR. & intermediate_timestep_count == 0 ) THEN sums_divold_l(0:statistic_regions) = localsum ENDIF CALL cpu_log( log_point_s(1), 'divergence', 'stop' ) ! !-- Compute the pressure perturbation solving the Poisson equation IF ( psolver == 'poisfft' ) THEN ! !-- Solve Poisson equation via FFT and solution of tridiagonal matrices CALL poisfft( d ) ! !-- Store computed perturbation pressure and set boundary condition in !-- z-direction !$OMP PARALLEL DO PRIVATE (i,j,k) !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) & !$ACC PRESENT(d, tend) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt tend(k,j,i) = d(k,j,i) ENDDO ENDDO ENDDO ! !-- Bottom boundary: !-- This condition is only required for internal output. The pressure !-- gradient (dp(nzb+1)-dp(nzb))/dz is not used anywhere else. IF ( ibc_p_b == 1 ) THEN ! !-- Neumann (dp/dz = 0). Using surfae data type, first for non-natural !-- surfaces, then for natural and urban surfaces !-- Upward facing !$OMP PARALLEL DO PRIVATE( i, j, k ) !$ACC PARALLEL LOOP PRIVATE(i, j, k) & !$ACC PRESENT(bc_h, tend) DO m = 1, bc_h(0)%ns i = bc_h(0)%i(m) j = bc_h(0)%j(m) k = bc_h(0)%k(m) tend(k-1,j,i) = tend(k,j,i) ENDDO ! !-- Downward facing !$OMP PARALLEL DO PRIVATE( i, j, k ) !$ACC PARALLEL LOOP PRIVATE(i, j, k) & !$ACC PRESENT(bc_h, tend) DO m = 1, bc_h(1)%ns i = bc_h(1)%i(m) j = bc_h(1)%j(m) k = bc_h(1)%k(m) tend(k+1,j,i) = tend(k,j,i) ENDDO ELSE ! !-- Dirichlet. Using surface data type, first for non-natural !-- surfaces, then for natural and urban surfaces !-- Upward facing !$OMP PARALLEL DO PRIVATE( i, j, k ) DO m = 1, bc_h(0)%ns i = bc_h(0)%i(m) j = bc_h(0)%j(m) k = bc_h(0)%k(m) tend(k-1,j,i) = 0.0_wp ENDDO ! !-- Downward facing !$OMP PARALLEL DO PRIVATE( i, j, k ) DO m = 1, bc_h(1)%ns i = bc_h(1)%i(m) j = bc_h(1)%j(m) k = bc_h(1)%k(m) tend(k+1,j,i) = 0.0_wp ENDDO ENDIF ! !-- Top boundary IF ( ibc_p_t == 1 ) THEN ! !-- Neumann !$OMP PARALLEL DO PRIVATE (i,j,k) DO i = nxlg, nxrg DO j = nysg, nyng tend(nzt+1,j,i) = tend(nzt,j,i) ENDDO ENDDO ELSE ! !-- Dirichlet !$OMP PARALLEL DO PRIVATE (i,j,k) !$ACC PARALLEL LOOP COLLAPSE(2) PRIVATE(i, j) & !$ACC PRESENT(tend) DO i = nxlg, nxrg DO j = nysg, nyng tend(nzt+1,j,i) = 0.0_wp ENDDO ENDDO ENDIF ! !-- Exchange boundaries for p CALL exchange_horiz( tend, nbgp ) ELSEIF ( psolver == 'sor' ) THEN ! !-- Solve Poisson equation for perturbation pressure using SOR-Red/Black !-- scheme CALL sor( d, ddzu_pres, ddzw, p_loc ) tend = p_loc ELSEIF ( psolver(1:9) == 'multigrid' ) THEN ! !-- Solve Poisson equation for perturbation pressure using Multigrid scheme, !-- array tend is used to store the residuals. !-- If the number of grid points of the gathered grid, which is collected !-- on PE0, is larger than the number of grid points of an PE, than array !-- tend will be enlarged. IF ( gathered_size > subdomain_size ) THEN DEALLOCATE( tend ) ALLOCATE( tend(nzb:nzt_mg(mg_switch_to_pe0_level)+1,nys_mg( & mg_switch_to_pe0_level)-1:nyn_mg(mg_switch_to_pe0_level)+1,& nxl_mg(mg_switch_to_pe0_level)-1:nxr_mg( & mg_switch_to_pe0_level)+1) ) ENDIF IF ( psolver == 'multigrid' ) THEN CALL poismg( tend ) ELSE CALL poismg_noopt( tend ) ENDIF IF ( gathered_size > subdomain_size ) THEN DEALLOCATE( tend ) ALLOCATE( tend(nzb:nzt+1,nysg:nyng,nxlg:nxrg) ) ENDIF ! !-- Restore perturbation pressure on tend because this array is used !-- further below to correct the velocity fields DO i = nxl-1, nxr+1 DO j = nys-1, nyn+1 DO k = nzb, nzt+1 tend(k,j,i) = p_loc(k,j,i) ENDDO ENDDO ENDDO ENDIF ! !-- Store perturbation pressure on array p, used for pressure data output. !-- Ghost layers are added in the output routines (except sor-method: see below) IF ( intermediate_timestep_count <= 1 ) THEN !$OMP PARALLEL PRIVATE (i,j,k) !$OMP DO !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) & !$ACC PRESENT(p, tend) DO i = nxl-1, nxr+1 DO j = nys-1, nyn+1 DO k = nzb, nzt+1 p(k,j,i) = tend(k,j,i) * & weight_substep_l ENDDO ENDDO ENDDO !$OMP END PARALLEL ELSEIF ( intermediate_timestep_count > 1 ) THEN !$OMP PARALLEL PRIVATE (i,j,k) !$OMP DO !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) & !$ACC PRESENT(p, tend) DO i = nxl-1, nxr+1 DO j = nys-1, nyn+1 DO k = nzb, nzt+1 p(k,j,i) = p(k,j,i) + tend(k,j,i) * & weight_substep_l ENDDO ENDDO ENDDO !$OMP END PARALLEL ENDIF ! !-- SOR-method needs ghost layers for the next timestep IF ( psolver == 'sor' ) CALL exchange_horiz( p, nbgp ) ! !-- Correction of the provisional velocities with the current perturbation !-- pressure just computed IF ( conserve_volume_flow .AND. ( bc_lr_cyc .OR. bc_ns_cyc ) ) THEN volume_flow_l(1) = 0.0_wp volume_flow_l(2) = 0.0_wp ENDIF ! !-- Add pressure gradients to the velocity components. Note, the loops are !-- running over the entire model domain, even though, in case of non-cyclic !-- boundaries u- and v-component are not prognostic at i=0 and j=0, !-- respectiveley. However, in case of Dirichlet boundary conditions for the !-- velocities, zero-gradient conditions for the pressure are set, so that !-- no modification is imposed at the boundaries. !$OMP PARALLEL PRIVATE (i,j,k) !$OMP DO !$ACC PARALLEL LOOP COLLAPSE(2) PRIVATE(i, j, k) & !$ACC PRESENT(u, v, w, tend, ddzu, wall_flags_0) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt w(k,j,i) = w(k,j,i) - dt_3d * & ( tend(k+1,j,i) - tend(k,j,i) ) * ddzu(k+1) & * weight_pres_l & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 3 ) & ) ENDDO DO k = nzb+1, nzt u(k,j,i) = u(k,j,i) - dt_3d * & ( tend(k,j,i) - tend(k,j,i-1) ) * ddx & * weight_pres_l & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 1 ) & ) ENDDO DO k = nzb+1, nzt v(k,j,i) = v(k,j,i) - dt_3d * & ( tend(k,j,i) - tend(k,j-1,i) ) * ddy & * weight_pres_l & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 2 ) & ) ENDDO ENDDO ENDDO !$OMP END PARALLEL ! !-- The vertical velocity is not set to zero at nzt + 1 for nested domains !-- Instead it is set to the values of nzt (see routine vnest_boundary_conds !-- or pmci_interp_tril_t) BEFORE calling the pressure solver. To avoid jumps !-- while plotting profiles w at the top has to be set to the values in the !-- height nzt after above modifications. Hint: w level nzt+1 does not impact !-- results. IF ( child_domain .OR. coupling_mode == 'vnested_fine' ) THEN w(nzt+1,:,:) = w(nzt,:,:) ENDIF ! !-- Sum up the volume flow through the right and north boundary IF ( conserve_volume_flow .AND. bc_lr_cyc .AND. bc_ns_cyc .AND. & nxr == nx ) THEN !$OMP PARALLEL PRIVATE (j,k) !$OMP DO DO j = nys, nyn !$OMP CRITICAL DO k = nzb+1, nzt volume_flow_l(1) = volume_flow_l(1) + u(k,j,nxr) * dzw(k) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,nxr), 1 )& ) ENDDO !$OMP END CRITICAL ENDDO !$OMP END PARALLEL ENDIF IF ( conserve_volume_flow .AND. bc_ns_cyc .AND. bc_lr_cyc .AND. & nyn == ny ) THEN !$OMP PARALLEL PRIVATE (i,k) !$OMP DO DO i = nxl, nxr !$OMP CRITICAL DO k = nzb+1, nzt volume_flow_l(2) = volume_flow_l(2) + v(k,nyn,i) * dzw(k) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,nyn,i), 2 )& ) ENDDO !$OMP END CRITICAL ENDDO !$OMP END PARALLEL ENDIF ! !-- Conserve the volume flow IF ( conserve_volume_flow .AND. ( bc_lr_cyc .AND. bc_ns_cyc ) ) THEN #if defined( __parallel ) IF ( collective_wait ) CALL MPI_BARRIER( comm2d, ierr ) CALL MPI_ALLREDUCE( volume_flow_l(1), volume_flow(1), 2, MPI_REAL, & MPI_SUM, comm2d, ierr ) #else volume_flow = volume_flow_l #endif volume_flow_offset(1:2) = ( volume_flow_initial(1:2) - volume_flow(1:2) ) / & volume_flow_area(1:2) !$OMP PARALLEL PRIVATE (i,j,k) !$OMP DO DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt u(k,j,i) = u(k,j,i) + volume_flow_offset(1) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 1 ) & ) ENDDO DO k = nzb+1, nzt v(k,j,i) = v(k,j,i) + volume_flow_offset(2) & * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 2 ) & ) ENDDO ENDDO ENDDO !$OMP END PARALLEL ENDIF ! !-- Exchange of boundaries for the velocities CALL exchange_horiz( u, nbgp ) CALL exchange_horiz( v, nbgp ) CALL exchange_horiz( w, nbgp ) ! !-- Compute the divergence of the corrected velocity field, !-- A possible PE-sum is computed in flow_statistics. Carry out computation !-- only at last Runge-Kutta step. IF ( intermediate_timestep_count == intermediate_timestep_count_max .OR. & intermediate_timestep_count == 0 ) THEN CALL cpu_log( log_point_s(1), 'divergence', 'start' ) sums_divnew_l = 0.0_wp ! !-- d must be reset to zero because it can contain nonzero values below the !-- topography IF ( topography /= 'flat' ) d = 0.0_wp localsum = 0.0_wp threadsum = 0.0_wp !$OMP PARALLEL PRIVATE (i,j,k) FIRSTPRIVATE(threadsum) REDUCTION(+:localsum) #if defined( __ibm ) !$OMP DO SCHEDULE( STATIC ) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt d(k,j,i) = ( ( u(k,j,i+1) - u(k,j,i) ) * rho_air(k) * ddx + & ( v(k,j+1,i) - v(k,j,i) ) * rho_air(k) * ddy + & ( w(k,j,i) * rho_air_zw(k) - & w(k-1,j,i) * rho_air_zw(k-1) ) * ddzw(k) & ) * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 0 ) & ) ENDDO DO k = nzb+1, nzt threadsum = threadsum + ABS( d(k,j,i) ) ENDDO ENDDO ENDDO #else !$OMP DO SCHEDULE( STATIC ) !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) & !$ACC PRESENT(u, v, w, rho_air, rho_air_zw, ddzw, wall_flags_0) & !$ACC PRESENT(d) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt d(k,j,i) = ( ( u(k,j,i+1) - u(k,j,i) ) * rho_air(k) * ddx + & ( v(k,j+1,i) - v(k,j,i) ) * rho_air(k) * ddy + & ( w(k,j,i) * rho_air_zw(k) - & w(k-1,j,i) * rho_air_zw(k-1) ) * ddzw(k) & ) * MERGE( 1.0_wp, 0.0_wp, & BTEST( wall_flags_0(k,j,i), 0 ) & ) ENDDO ENDDO ENDDO ! !-- Compute possible PE-sum of divergences for flow_statistics !$OMP DO SCHEDULE( STATIC ) !$ACC PARALLEL LOOP COLLAPSE(3) PRIVATE(i, j, k) & !$ACC REDUCTION(+:threadsum) COPY(threadsum) & !$ACC PRESENT(d) DO i = nxl, nxr DO j = nys, nyn DO k = nzb+1, nzt threadsum = threadsum + ABS( d(k,j,i) ) ENDDO ENDDO ENDDO #endif localsum = localsum + threadsum !$OMP END PARALLEL ! !-- For completeness, set the divergence sum of all statistic regions to those !-- of the total domain sums_divnew_l(0:statistic_regions) = localsum CALL cpu_log( log_point_s(1), 'divergence', 'stop' ) ENDIF CALL cpu_log( log_point(8), 'pres', 'stop' ) END SUBROUTINE pres