إضافة ملف nswe_solver.f90 في المسار الصحيح

src/core/nswe_solver.f90

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+! TSU-WAVE NSWE Solver (Fortran 90)
+! Nonlinear Shallow-Water Equations for Tsunami Propagation
+
+module nswe_solver
+  implicit none
+  real, parameter :: g = 9.81  ! gravity
+  real, parameter :: rho = 1025.0  ! seawater density
+  
+contains
+
+  subroutine solve_nswe(eta, u, v, H, nx, ny, dt, dx, dy, nt)
+    ! Solve 2D Nonlinear Shallow-Water Equations
+    implicit none
+    integer, intent(in) :: nx, ny, nt
+    real, intent(inout) :: eta(nx, ny), u(nx, ny), v(nx, ny)
+    real, intent(in) :: H(nx, ny)
+    real, intent(in) :: dt, dx, dy
+    
+    integer :: i, j, t
+    real :: eta_new(nx, ny), u_new(nx, ny), v_new(nx, ny)
+    real :: du_dx, du_dy, dv_dx, dv_dy, deta_dx, deta_dy
+    
+    do t = 1, nt
+      ! Continuity equation
+      do i = 2, nx-1
+        do j = 2, ny-1
+          du_dx = (u(i+1,j) - u(i-1,j)) / (2*dx)
+          dv_dy = (v(i,j+1) - v(i,j-1)) / (2*dy)
+          eta_new(i,j) = eta(i,j) - dt * ((H(i,j) + eta(i,j)) * (du_dx + dv_dy))
+        end do
+      end do
+      
+      ! Momentum equations (simplified)
+      do i = 2, nx-1
+        do j = 2, ny-1
+          deta_dx = (eta_new(i+1,j) - eta_new(i-1,j)) / (2*dx)
+          u_new(i,j) = u(i,j) - dt * (u(i,j) * (u(i+1,j)-u(i-1,j))/(2*dx) + &
+                                       v(i,j) * (u(i,j+1)-u(i,j-1))/(2*dy) + &
+                                       g * deta_dx)
+          
+          deta_dy = (eta_new(i,j+1) - eta_new(i,j-1)) / (2*dy)
+          v_new(i,j) = v(i,j) - dt * (u(i,j) * (v(i+1,j)-v(i-1,j))/(2*dx) + &
+                                       v(i,j) * (v(i,j+1)-v(i,j-1))/(2*dy) + &
+                                       g * deta_dy)
+        end do
+      end do
+      
+      ! Update boundaries
+      call apply_boundary_conditions(eta_new, u_new, v_new, nx, ny)
+      
+      ! Copy back
+      eta = eta_new
+      u = u_new
+      v = v_new
+    end do
+    
+  end subroutine solve_nswe
+  
+  subroutine apply_boundary_conditions(eta, u, v, nx, ny)
+    implicit none
+    integer, intent(in) :: nx, ny
+    real, intent(inout) :: eta(nx, ny), u(nx, ny), v(nx, ny)
+    integer :: i, j
+    
+    ! Zero-gradient at boundaries
+    ! Left boundary
+    eta(1,:) = eta(2,:)
+    u(1,:) = u(2,:)
+    v(1,:) = v(2,:)
+    
+    ! Right boundary
+    eta(nx,:) = eta(nx-1,:)
+    u(nx,:) = u(nx-1,:)
+    v(nx,:) = v(nx-1,:)
+    
+    ! Bottom boundary
+    eta(:,1) = eta(:,2)
+    u(:,1) = u(:,2)
+    v(:,1) = v(:,2)
+    
+    ! Top boundary
+    eta(:,ny) = eta(:,ny-1)
+    u(:,ny) = u(:,ny-1)
+    v(:,ny) = v(:,ny-1)
+    
+  end subroutine apply_boundary_conditions
+
+end module nswe_solver