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pbl_solver.f90 3.6 KiB
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  • ! Created by Andrey Debolskiy on 29.11.2024.
    
    module pbl_solver
        use parkinds, only: rf=>kind_rf, im=>kind_im
        use scm_state_data
        use pbl_turb_data
        implicit none
    
        public factorize_tridiag
        public solve_tridiag
        public fill_tridiag
        public solve_diffusion
        contains
        subroutine factorize_tridiag(ktvd, kl, aa, bb, cc, prgna, prgnz)
            implicit none
            integer, intent(in)              :: ktvd, kl
            real, intent(in),  dimension(kl) :: aa, bb, cc
            real, intent(out), dimension(kl) :: prgna, prgnz
    
            integer :: k
    
            prgna(ktvd) = cc(ktvd) / bb(ktvd)
            do k = ktvd+1, kl
                prgnz(k) = 1.0e0 / (bb(k) - aa(k) * prgna(k-1))
                prgna(k) = cc(k) * prgnz(k)
            end do
        end subroutine factorize_tridiag
    
        !> reduce tridiagonal system to bidiagonal after matrix factorization
        !!              - bb(k) y(k) + cc(k) y(k+1) = -f(k), k = ktvd
        !! aa(k) y(k-1) - bb(k) y(k) + cc(k) y(k+1) = -f(k), k = ktvd+1..kl-1
        !! aa(k) y(k-1) - bb(k) y(k)                = -f(k), k = kl
        !! assuming cc(kl) = 0.0
        !! reduced system is
        !! y(k) - prgna(k) y(k+1) = prgnb(k), k = ktvd..kl-1
        !! y(k)                   = prgnb(k), k = kl
        !! then solve via backward substitution
        subroutine solve_tridiag(ktvd, kl, aa, bb, cc, ff, prgna, prgnz, y)
            implicit none
            integer, intent(in)              :: ktvd, kl
            real, intent(in),  dimension(kl) :: aa, bb, cc, ff
            real, intent(in),  dimension(kl) :: prgna, prgnz
            real, intent(out), dimension(kl) :: y
    
            integer :: k
            real :: prgnb(kl)
    
            prgnb(ktvd) = ff(ktvd) / bb(ktvd)
            do k = ktvd+1, kl
                prgnb(k) = prgnz(k) * (ff(k) + aa(k) * prgnb(k-1))
            end do
            y(kl) = prgnb(kl)
            do k = kl-1, ktvd, -1
                y(k) = prgna(k) * y(k+1) + prgnb(k)
            end do
        end subroutine solve_tridiag
    
        subroutine fill_tridiag(aa, bb, cc, rho, kdiff, kbltop, grid, dt)
            use pbl_grid, only: pblgridDataType
            implicit none
            real, dimension(*), intent(in):: rho, kdiff
            real, intent(in):: dt
            integer, intent(in):: kbltop
            type(pblgridDataType),intent(in):: grid
    
            real, dimension(*), intent(out):: aa, bb, cc
    
            real:: dtdz
            integer:: k
    
            !nulify before top boundary
            aa(1:kbltop) = 0.0
            bb(1:kbltop) = 0.0
            cc(1:kbltop) = 0.0
            !top boundary condition: flux = 0
            k = kbltop
            dtdz = dt / (grid%dzc(k))
            aa(k) = 0
            cc(k) = (kdiff(k)/rho(k)) * dtdz / grid%dze(k)
    
            do k = kbltop + 1, grid%kmax -1
                dtdz = dt / (grid%dzc(k))
                aa(k) = (kdiff(k - 1)/rho(k)) * dtdz / grid%dze(k-1)
                cc(k) = (kdiff(k)/rho(k)) * dtdz / grid%dze(k)
                bb(k) = 1.0 + aa(k) + cc(k)
            end do
    
            !bottom boundary
            k = grid%kmax
            dtdz = dt / (grid%dzc(k))
            aa(k) = (kdiff(k-1)/rho(k)) * dtdz / grid%dze(k-1)
            bb(k) = 1.0 + aa(k)
            cc(k) = 0.0
        end subroutine fill_tridiag
    
        subroutine solve_diffusion(bl, bl_old, turb, fluid, grid)
            use scm_state_data, only : stateBLDataType
            use pbl_turb_data, only : turbBLDataType
            use phys_fluid, only: fluidParamsDataType
            use pbl_grid, only : pblgridDataType
            implicit none
            type(stateBLDataType), intent(out):: bl
            type(stateBLDataType), intent(in):: bl_old
            type(turbBLDataType), intent(in):: turb
            type(fluidParamsDataType), intent(in) :: fluid
            type(pblgridDataType), intent(in) :: grid
    
        end subroutine solve_diffusion
    end module pbl_solver