From b42b46dd749f22a7317bba70c0013d437b619143 Mon Sep 17 00:00:00 2001
From: Semih Akkurt <s.akkurt18@imperial.ac.uk>
Date: Fri, 20 Dec 2024 19:49:57 +0000
Subject: [PATCH] Add channel case.

---
 examples/channel/input.x3d | 31 +++++++++++++++
 src/CMakeLists.txt         |  1 +
 src/case/channel.f90       | 77 ++++++++++++++++++++++++++++++++++++++
 src/xcompact.f90           |  4 ++
 4 files changed, 113 insertions(+)
 create mode 100644 examples/channel/input.x3d
 create mode 100644 src/case/channel.f90

diff --git a/examples/channel/input.x3d b/examples/channel/input.x3d
new file mode 100644
index 00000000..322c6a64
--- /dev/null
+++ b/examples/channel/input.x3d
@@ -0,0 +1,31 @@
+&domain_settings
+! Flow case
+flow_case_name = 'channel'
+
+! Global domain length
+L_global = 8d0, 2d0, 4d0
+
+! Global number of cells in each direction
+dims_global = 256, 257, 128
+
+! Domain decomposition in each direction
+nproc_dir = 1, 1, 2
+
+! BC options are 'periodic' | 'neumann' | 'dirichlet'
+BC_x = 'periodic', 'periodic'
+BC_y = 'dirichlet', 'dirichlet'
+BC_z = 'periodic', 'periodic'
+/End
+
+&solver_params
+Re = 4200d0
+time_intg = 'AB3' ! 'AB[1-4]' | 'RK[1-4]'
+dt = 0.005d0
+n_iters = 100000
+n_output = 1000
+poisson_solver_type = 'FFT' ! 'FFT' | 'CG'
+der1st_scheme = 'compact6'
+der2nd_scheme = 'compact6' ! 'compact6' | 'compact6-hyperviscous'
+interpl_scheme = 'optimised' ! 'classic' | 'optimised' | 'aggressive'
+stagder_scheme = 'compact6'
+/End
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 8db0c706..d1b44201 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -11,6 +11,7 @@ set(SRC
   time_integrator.f90
   vector_calculus.f90
   case/base_case.f90
+  case/channel.f90
   case/generic.f90
   case/tgv.f90
   omp/backend.f90
diff --git a/src/case/channel.f90 b/src/case/channel.f90
new file mode 100644
index 00000000..3e140797
--- /dev/null
+++ b/src/case/channel.f90
@@ -0,0 +1,77 @@
+module m_case_channel
+  use iso_fortran_env, only: stderr => error_unit
+
+  use m_allocator, only: allocator_t, field_t
+  use m_base_backend, only: base_backend_t
+  use m_base_case, only: base_case_t
+  use m_common, only: dp
+  use m_mesh, only: mesh_t
+  use m_solver, only: init
+
+  implicit none
+
+  type, extends(base_case_t) :: case_channel_t
+  contains
+    procedure :: boundary_conditions => boundary_conditions_channel
+    procedure :: initial_conditions => initial_conditions_channel
+    procedure :: post_transeq => post_transeq_channel
+    procedure :: postprocess => postprocess_channel
+  end type case_channel_t
+
+  interface case_channel_t
+    module procedure case_channel_init
+  end interface case_channel_t
+
+contains
+
+  function case_channel_init(backend, mesh, host_allocator) result(flow_case)
+    implicit none
+
+    class(base_backend_t), target, intent(inout) :: backend
+    type(mesh_t), target, intent(inout) :: mesh
+    type(allocator_t), target, intent(inout) :: host_allocator
+    type(case_channel_t) :: flow_case
+
+    call flow_case%case_init(backend, mesh, host_allocator)
+
+  end function case_channel_init
+
+  subroutine boundary_conditions_channel(self)
+    implicit none
+
+    class(case_channel_t) :: self
+
+  end subroutine boundary_conditions_channel
+
+  subroutine initial_conditions_channel(self)
+    implicit none
+
+    class(case_channel_t) :: self
+
+    call self%solver%u%fill(1._dp)
+    call self%solver%v%fill(0._dp)
+    call self%solver%w%fill(0._dp)
+
+  end subroutine initial_conditions_channel
+
+  subroutine postprocess_channel(self, t)
+    implicit none
+
+    class(case_channel_t) :: self
+    real(dp), intent(in) :: t
+
+    if (self%solver%mesh%par%is_root()) print *, 'time =', t
+    call self%print_enstrophy(self%solver%u, self%solver%v, self%solver%w)
+    call self%print_div_max_mean(self%solver%u, self%solver%v, self%solver%w)
+
+  end subroutine postprocess_channel
+
+  subroutine post_transeq_channel(self, du, dv, dw)
+    implicit none
+
+    class(case_channel_t) :: self
+    class(field_t), intent(inout) :: du, dv, dw
+
+  end subroutine post_transeq_channel
+
+end module m_case_channel
diff --git a/src/xcompact.f90 b/src/xcompact.f90
index da9ac4aa..30138772 100644
--- a/src/xcompact.f90
+++ b/src/xcompact.f90
@@ -8,6 +8,7 @@ program xcompact
   use m_solver, only: solver_t
   use m_tdsops, only: tdsops_t
   use m_mesh
+  use m_case_channel, only: case_channel_t
   use m_case_generic, only: case_generic_t
   use m_case_tgv, only: case_tgv_t
 
@@ -108,6 +109,9 @@ program xcompact
   if (nrank == 0) print *, 'Flow case: ', flow_case_name
 
   select case (trim(flow_case_name))
+  case ('channel')
+    allocate (case_channel_t :: flow_case)
+    flow_case = case_channel_t(backend, mesh, host_allocator)
   case ('generic')
     allocate (case_generic_t :: flow_case)
     flow_case = case_generic_t(backend, mesh, host_allocator)