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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,119 @@ | ||
| #!/usr/bin/env python3 | ||
| """ | ||
| NACA 0012 at M = 0.3, alpha = 2 deg, 200 cells per chord: the 2D_ibm_airfoil_surface_pressure example | ||
| switched to a viscous no-slip wall (Re = 1000 per chord), with frequent snapshots for time averaging. | ||
| Env: RE, T_STOP, T_SAVE, SECOND_ORDER=1 (PR branch only: second-order IB velocities). | ||
| """ | ||
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| import json | ||
| import math | ||
| import os | ||
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| Ma = 0.3 | ||
| alpha_deg = 2.0 | ||
| gamma = 1.4 | ||
| rho_inf, U_inf, chord = 1.0, 1.0, 1.0 | ||
| Re = float(os.environ.get("RE", 1000.0)) | ||
| P_inf = rho_inf * U_inf**2 / (gamma * Ma**2) | ||
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| case = { | ||
| # --- Output --- | ||
| "run_time_info": "T", | ||
| "format": 2, | ||
| "precision": 2, | ||
| "parallel_io": "T", | ||
| "prim_vars_wrt": "T", | ||
| # --- Domain: pre-stretch extents; the stretching maps them outward --- | ||
| "x_domain%beg": -3.0, | ||
| "x_domain%end": 4.0, | ||
| "y_domain%beg": -3.0, | ||
| "y_domain%end": 3.0, | ||
| "m": 1399, | ||
| "n": 1199, | ||
| "p": 0, | ||
| "cyl_coord": "F", | ||
| "stretch_x": "T", | ||
| "a_x": 15.0, | ||
| "x_a": -0.8, | ||
| "x_b": 1.8, | ||
| "loops_x": 2, | ||
| "stretch_y": "T", | ||
| "a_y": 15.0, | ||
| "y_a": -0.7, | ||
| "y_b": 0.7, | ||
| "loops_y": 2, | ||
| # --- Time stepping --- | ||
| "cfl_adap_dt": "T", | ||
| "cfl_target": 0.5, | ||
| "n_start": 0, | ||
| "t_save": 0.2, | ||
| "t_stop": 6.0, | ||
| # --- Numerics --- | ||
| "num_patches": 1, | ||
| "num_fluids": 1, | ||
| "model_eqns": 2, | ||
| "alt_soundspeed": "F", | ||
| "mpp_lim": "F", | ||
| "mixture_err": "T", | ||
| "time_stepper": 3, | ||
| "weno_order": 5, | ||
| "weno_eps": 1.0e-10, | ||
| "weno_Re_flux": "F", | ||
| "weno_avg": "T", | ||
| "avg_state": 2, | ||
| "mapped_weno": "T", | ||
| "null_weights": "F", | ||
| "mp_weno": "F", | ||
| "riemann_solver": 2, | ||
| "low_Mach": 2, | ||
| "wave_speeds": 1, | ||
| "viscous": "T", | ||
| "fd_order": 4, | ||
| # --- Uniform freestream --- | ||
| "patch_icpp(1)%geometry": 3, | ||
| "patch_icpp(1)%x_centroid": 0.0, | ||
| "patch_icpp(1)%y_centroid": 0.0, | ||
| "patch_icpp(1)%length_x": 1.0e3, | ||
| "patch_icpp(1)%length_y": 1.0e3, | ||
| "patch_icpp(1)%vel(1)": U_inf, | ||
| "patch_icpp(1)%vel(2)": 0.0, | ||
| "patch_icpp(1)%pres": P_inf, | ||
| "patch_icpp(1)%alpha_rho(1)": rho_inf, | ||
| "patch_icpp(1)%alpha(1)": 1.0, | ||
| "fluid_pp(1)%gamma": 1.0 / (gamma - 1.0), | ||
| "fluid_pp(1)%eos": "ideal_gas", | ||
| "fluid_pp(1)%Re(1)": Re, | ||
| # --- Characteristic far-field boundaries --- | ||
| "bc_x%beg": -7, | ||
| "bc_x%grcbc_in": "T", | ||
| "bc_x%vel_in(1)": U_inf, | ||
| "bc_x%vel_in(2)": 0.0, | ||
| "bc_x%pres_in": P_inf, | ||
| "bc_x%alpha_rho_in(1)": rho_inf, | ||
| "bc_x%alpha_in(1)": 1.0, | ||
| "bc_x%end": -8, | ||
| "bc_x%grcbc_out": "T", | ||
| "bc_x%pres_out": P_inf, | ||
| "bc_y%beg": -9, | ||
| "bc_y%end": -9, | ||
| # --- IB: NACA 0012 (m must be > 0, so a negligible camber stands in for 0) --- | ||
| "ib": "T", | ||
| "num_ibs": 1, | ||
| "patch_ib(1)%geometry": 4, | ||
| "patch_ib(1)%x_centroid": 0.0, | ||
| "patch_ib(1)%y_centroid": 0.0, | ||
| "patch_ib(1)%airfoil_id": 1, | ||
| "patch_ib(1)%angles(3)": -math.radians(alpha_deg), | ||
| "patch_ib(1)%slip": "F", | ||
| "patch_ib(1)%moving_ibm": 0, | ||
| "ib_airfoil(1)%c": chord, | ||
| "ib_airfoil(1)%t": 0.12, | ||
| "ib_airfoil(1)%p": 0.4, | ||
| "ib_airfoil(1)%m": 1.0e-9, | ||
| } | ||
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| # the parameters for second-order IBM | ||
| case.update({"ib_second_order_vel": "T", "ib_ip_min_dist": 1.5}) | ||
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| print(json.dumps(case, indent=4)) |
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| Original file line number | Diff line number | Diff line change |
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@@ -30,7 +30,7 @@ module m_ibm | |
| implicit none | ||
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| private :: s_compute_image_points, s_compute_interpolation_coeffs, s_interpolate_image_point, s_find_ghost_points, & | ||
| & s_find_num_ghost_points, s_compute_ghost_point_pressure, s_compute_ghost_point_velocity, s_interpolation_weights | ||
| ; public :: s_initialize_ibm_module, s_ibm_setup, s_ibm_correct_state, s_finalize_ibm_module, s_report_ibm_surface | ||
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| !> Ghost points at which the reacting-surface Newton solve did not reach its tolerance, so the point fell back to a chemically | ||
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@@ -85,6 +85,7 @@ contains | |
| @:ACC_SETUP_SFs(corrected_gps) | ||
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| $:GPU_ENTER_DATA(copyin='[num_gps]') | ||
| $:GPU_UPDATE(device='[ib_second_order_vel, ib_ip_min_dist]') | ||
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| if (collision_model > 0) call s_initialize_collisions_module() | ||
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@@ -193,7 +194,7 @@ contains | |
| real(wp), intent(in) :: rho, pres_IP | ||
| real(wp), intent(out) :: pres_GP | ||
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| pres_GP = pres_IP/min(max(1._wp - (abs(gp%levelset) + gp%ip_dist) & | ||
| & *rho/pres_IP*dot_product(patch_ib(gp_patch_id)%force/patch_ib(gp_patch_id)%mass, & | ||
| & gp%levelset_norm), 5.e-1_wp), 2._wp) | ||
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@@ -257,6 +258,9 @@ contains | |
| if (buf > 0._wp) vel_GP = vel_GP + v_blow_eff*norm/buf | ||
| end if | ||
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| ! extrapolate linearly through the boundary intercept, Mittal et al. (2008) | ||
| if (ib_second_order_vel) vel_GP = vel_GP - abs(gp%levelset)/max(gp%ip_dist, sgm_eps)*(vel_IP - vel_GP) | ||
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| end subroutine s_compute_ghost_point_velocity | ||
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| !> Update the conservative variables at the ghost points | ||
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@@ -706,6 +710,7 @@ contains | |
| impure subroutine s_compute_image_points() | ||
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| real(wp) :: dist | ||
| real(wp) :: min_cell_width | ||
| real(wp), dimension(3) :: norm | ||
| real(wp), dimension(3) :: physical_loc | ||
| real(wp) :: temp_loc | ||
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@@ -721,8 +726,8 @@ contains | |
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| bounds_error = .false. | ||
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| $:GPU_PARALLEL_LOOP(private='[q, gp, i, j, k, physical_loc, patch_id, dist, min_cell_width, norm, dim, bound, dir, index, & | ||
| & temp_loc, s_cc]', copy='[bounds_error]', present='[ghost_points]') | ||
| do q = 1, num_gps | ||
| gp = ghost_points(q) | ||
| i = gp%loc(1) | ||
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@@ -740,7 +745,14 @@ contains | |
| patch_id = gp%ib_patch_id | ||
| dist = abs(real(gp%levelset, kind=wp)) | ||
| norm(:) = gp%levelset_norm | ||
| ghost_points(q)%ip_dist = dist | ||
| ! keep the image point stencil off the wall | ||
| if (ib_second_order_vel) then | ||
| min_cell_width = min(dx(i), dy(j)) | ||
| if (p > 0) min_cell_width = min(min_cell_width, dz(k)) | ||
| ghost_points(q)%ip_dist = max(dist, ib_ip_min_dist*min_cell_width) | ||
|
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| end if | ||
| ghost_points(q)%ip_loc(:) = physical_loc(:) + (dist + ghost_points(q)%ip_dist)*norm(:) | ||
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| ! Find the closest grid point to the image point | ||
| do dim = 1, num_dims | ||
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@@ -931,16 +943,12 @@ contains | |
| subroutine s_compute_interpolation_coeffs() | ||
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| real(wp), dimension(2, 2, 2) :: dist | ||
| real(wp), dimension(2, 2, 2) :: fluid_mask | ||
| real(wp), dimension(2, 2, 2) :: interp_coeffs | ||
| type(ghost_point) :: gp | ||
| integer :: q, i, j, k, ii, jj, kk !< Grid indexes and iterators | ||
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| $:GPU_PARALLEL_LOOP(private='[q, i, j, k, ii, jj, kk, dist, gp, interp_coeffs, fluid_mask]', present='[ghost_points]') | ||
| do q = 1, num_gps | ||
| gp = ghost_points(q) | ||
| ! Get the interpolation points | ||
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@@ -954,7 +962,6 @@ contains | |
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| ! get the distance to a cell in each direction | ||
| dist = 0._wp | ||
| do ii = 0, 1 | ||
| do jj = 0, 1 | ||
| if (p == 0) then | ||
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@@ -969,51 +976,17 @@ contains | |
| end do | ||
| end do | ||
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| ! flag the fluid cells of the stencil | ||
| fluid_mask = 0._wp | ||
| do kk = 0, min(p, 1) | ||
| do jj = 0, 1 | ||
| do ii = 0, 1 | ||
| if (ib_markers%sf(i + ii, j + jj, k + kk) == 0) fluid_mask(ii + 1, jj + 1, kk + 1) = 1._wp | ||
| end do | ||
| end do | ||
| end do | ||
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| call s_interpolation_weights(gp, i, j, k, dist, fluid_mask, interp_coeffs) | ||
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| ! An image point buried in a neighboring IB gets no weights at all: its ghost point is | ||
| ! averaged from its own neighbors instead, in s_ibm_correct_state. | ||
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@@ -1025,6 +998,53 @@ contains | |
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| end subroutine s_compute_interpolation_coeffs | ||
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| !> Fluid-masked image-point weights: bilinear for second-order IBM, else inverse distance squared | ||
| subroutine s_interpolation_weights(gp, i, j, k, dist, fluid_mask, interp_coeffs) | ||
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| $:GPU_ROUTINE(parallelism='[seq]') | ||
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| type(ghost_point), intent(in) :: gp | ||
| integer, intent(in) :: i, j, k !< lower corner of the stencil | ||
| real(wp), dimension(2, 2, 2), intent(in) :: dist, fluid_mask | ||
| real(wp), dimension(2, 2, 2), intent(out) :: interp_coeffs | ||
| real(wp), dimension(2, 2, 2) :: weights | ||
| real(wp), dimension(2, 3) :: axis_weight !< (stencil side, dimension) linear weights | ||
| real(wp) :: weight_sum | ||
| integer :: ii, jj, kk, num_z_layers | ||
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| num_z_layers = min(p, 1) + 1 | ||
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| if (ib_second_order_vel) then | ||
| ! bilinear weights, Mittal et al. (2008) | ||
| axis_weight(2, 1) = (gp%ip_loc(1) - x_cc(i))/(x_cc(i + 1) - x_cc(i)) | ||
| axis_weight(2, 2) = (gp%ip_loc(2) - y_cc(j))/(y_cc(j + 1) - y_cc(j)) | ||
| axis_weight(2, 3) = 0._wp | ||
| if (p /= 0) axis_weight(2, 3) = (gp%ip_loc(3) - z_cc(k))/(z_cc(k + 1) - z_cc(k)) | ||
| axis_weight(2,:) = min(max(axis_weight(2,:), 0._wp), 1._wp) ! clamp to the cell edges | ||
| axis_weight(1,:) = 1._wp - axis_weight(2,:) | ||
| do kk = 1, num_z_layers | ||
| do jj = 1, 2 | ||
| do ii = 1, 2 | ||
| weights(ii, jj, kk) = axis_weight(ii, 1)*axis_weight(jj, 2)*axis_weight(kk, 3) | ||
| end do | ||
| end do | ||
| end do | ||
| else | ||
| ! inverse distance squared, Chaudhuri et al. JCP (2011) | ||
| if (minval(dist(:,:,1:num_z_layers)) <= 1.e-16_wp) then | ||
| weights(:,:,1:num_z_layers) = merge(1._wp, 0._wp, dist(:,:,1:num_z_layers) <= 1.e-16_wp) | ||
| else | ||
| weights(:,:,1:num_z_layers) = 1._wp/dist(:,:,1:num_z_layers)**2 | ||
| end if | ||
| end if | ||
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| interp_coeffs = 0._wp | ||
| weights(:,:,1:num_z_layers) = fluid_mask(:,:,1:num_z_layers)*weights(:,:,1:num_z_layers) | ||
| weight_sum = sum(weights(:,:,1:num_z_layers)) | ||
| if (weight_sum > 0._wp) interp_coeffs(:,:,1:num_z_layers) = weights(:,:,1:num_z_layers)/weight_sum | ||
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| end subroutine s_interpolation_weights | ||
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| !> Interpolate primitive variables to a ghost point's image point using bilinear or trilinear interpolation | ||
| subroutine s_interpolate_image_point(q_prim_vf, gp, alpha_rho_IP, alpha_IP, pres_IP, vel_IP, c_IP, r_IP, v_IP, pb_IP, mv_IP, & | ||
| & nmom_IP, pb_in, mv_in, presb_IP, massv_IP, Ys_IP) | ||
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For an image point that is not symmetrically placed among its stencil centers,
vel_IPcomes froms_compute_interpolation_coeffs, whose normalized1/dist**2weights at lines 1017-1028 do not reproduce even a linear velocity field. This new no-slip extrapolation therefore propagates an O(h) image-velocity error into the ghost value and cannot provide the advertised second-order surface velocity; use bilinear/trilinear linear-exact weights or an equivalent correction. The addedCircle -> second order velgoldens use only onen=49grid, so they cannot verify the claimed convergence order.AGENTS.md reference: AGENTS.md:L5-L5
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