merge upstream/master

Author: wilfonba

docs/documentation/case.md

@@ -455,6 +455,7 @@ See @ref equations "Equations" for the mathematical models these parameters cont
 | `mp_weno`                  | Logical | Monotonicity preserving WENO |
 | `muscl_order`              | Integer | MUSCL order [1,2] |
 | `muscl_lim`                | Integer | MUSCL Slope Limiter: [1] minmod; [2] monotonized central; [3] Van Albada; [4] Van Leer; [5] SUPERBEE |
+| `muscl_eps`                | Real    | MUSCL limiter slope-product threshold (default: hard-coded thresholds; set to 0 for textbook behavior) |
 | `flux_lim`                 | Integer | Flux limiter for post-process: [1] minmod; [2] MUSCL; [3] OSPRE; [4] SUPERBEE |
 | `int_comp`                 | Logical | THINC Interface Compression |
 | `ic_eps`                   | Real    | Interface compression threshold (default: 1e-4) |
@@ -552,6 +553,10 @@ It is recommended to set `weno_eps` to $10^{-6}$ for WENO-JS, and to $10^{-40}$
 - `muscl_lim` specifies the slope limiter that is used in 2nd order MUSCL Reconstruction by an integer from 1 through 5.
 `muscl_lim = 1`, `2`, `3`, `4`, and `5` correspond to minmod, monotonized central, Van Albada, Van Leer, and SUPERBEE, respectively.
 
+- `muscl_eps` controls the slope-product activation threshold for all MUSCL limiters.
+When not set (default), the threshold is 1e-9 for minmod/MC, and 1e-6 for others.
+Setting `muscl_eps = 0` gives textbook limiter behavior where limiters activate whenever both slopes have the same sign.
+
 - `int_comp` activates interface compression using THINC used in MUSCL Reconstruction, with control parameters (`ic_eps`, and `ic_beta`).
 
 - `riemann_solver` specifies the choice of the Riemann solver that is used in simulation by an integer from 1 through 4.

docs/index.html

@@ -58,6 +58,7 @@
             { name: "Mach 0.3 flow over a corgi (2M STL)", image: "res/simulations/u.png", computer: "HiPerGator", computerUrl: "https://www.rc.ufl.edu/about/hipergator/",                                     accelerators: "2 GPUs",    walltime: "80s",  source: "https://www.youtube.com/watch?v=O8dSRqHLp_o" },
             // Shock-droplet
             { name: "Shedding water droplet",              image: "res/simulations/a.png", computer: "Summit",     computerUrl: "https://www.olcf.ornl.gov/summit/",                                            accelerators: "960 V100s", walltime: "4h",   source: "https://www.youtube.com/watch?v=Gjj-qZkXcrg" },
+            { name: "1K resolved particles",               image: "res/simulations/x.jpg", computer: "Phoenix",    computerUrl: "https://www.pace.gatech.edu/",                                                 accelerators: "4 A100s",   walltime: "~1.5h", source: "https://www.youtube.com/watch?v=ufisHG0KkOU" },
             // Biomedical & acoustics
             { name: "Burstwave lithotripsy",               image: "res/simulations/k.png", computer: "Delta",      computerUrl: "https://www.ncsa.illinois.edu/research/project-highlights/delta/",              accelerators: "128 A100s", walltime: "30m",  source: "https://www.youtube.com/watch?v=XWsUTaJXGF8" },
             { name: "Cavitation fragments kidney stone",   image: "res/simulations/d.png", computer: "Summit",     computerUrl: "https://www.olcf.ornl.gov/summit/",                                            accelerators: "576 V100s", walltime: "30m",  source: "https://doi.org/10.48550/arXiv.2305.09163" },
@@ -74,6 +75,7 @@
             { name: "Breakup of vibrated interface",       image: "res/simulations/f.png", computer: "Summit",     computerUrl: "https://www.olcf.ornl.gov/summit/",                                            accelerators: "128 V100s", walltime: "4h",   source: "https://www.youtube.com/watch?v=XQ3g1oSg8mc" },
             { name: "Viscous Taylor-Green vortex",         image: "res/simulations/h.png", computer: "Delta",      computerUrl: "https://www.ncsa.illinois.edu/research/project-highlights/delta/",              accelerators: "128 A100s", walltime: "17h",  source: "https://www.youtube.com/watch?v=7i2h08dlDQw" },
             { name: "Mach 1.5 shock-helium bubble",        image: "res/simulations/t.png", computer: "Phoenix",    computerUrl: "https://www.pace.gatech.edu/",                                                 accelerators: "1 A100",    walltime: "1h",   source: "https://www.youtube.com/watch?v=zDJoe0NYZsQ" },
+            { name: "Sphere collision and wall rebound",   image: "res/simulations/w.jpg", computer: "Phoenix",    computerUrl: "https://www.pace.gatech.edu/",                                                 accelerators: "4 A100s",   walltime: "~2h",   source: "https://www.youtube.com/watch?v=5ugLuDtV0C0" },
         ];
 
         const scalings = [

docs/res/simulations/w.jpg

@@ -152,6 +152,7 @@ module m_global_parameters
     logical :: nv_uvm_pref_gpu  !< Enable explicit gpu memory hints (default FALSE)
     !> @}
 
+    real(wp)           :: muscl_eps                    !< MUSCL limiter slope-product threshold
     real(wp)           :: weno_eps                     !< Binding for the WENO nonlinear weights
     real(wp)           :: teno_CT                      !< Smoothness threshold for TENO
     logical            :: mp_weno                      !< Monotonicity preserving (MP) WENO
@@ -201,6 +202,7 @@ module m_global_parameters
         $:GPU_DECLARE(create='[recon_type, muscl_order, muscl_polyn, muscl_lim]')
     #:endif
 
+    $:GPU_DECLARE(create='[muscl_eps]')
     $:GPU_DECLARE(create='[mpp_lim, model_eqns, mixture_err, alt_soundspeed]')
     $:GPU_DECLARE(create='[avg_state, mp_weno, weno_eps, teno_CT, hypoelasticity]')
     $:GPU_DECLARE(create='[hyperelasticity, hyper_model, elasticity, low_Mach]')
@@ -547,6 +549,7 @@ contains
         model_eqns = dflt_int
         mpp_lim = .false.
         time_stepper = dflt_int
+        muscl_eps = dflt_real
         weno_eps = dflt_real
         teno_CT = dflt_real
         mp_weno = .false.
@@ -892,7 +895,16 @@ contains
             $:GPU_UPDATE(device='[igr, igr_order, igr_iter_solver]')
         #:endif
 
-        ! Initialize viscous fluid count and curvature tracking
+        ! muscl_eps: use per-limiter defaults when user did not set it
+        if (f_is_default(muscl_eps)) then
+            if (muscl_lim <= 2) then
+                muscl_eps = 1e-9_wp  ! minmod, MC
+            else
+                muscl_eps = 1e-6_wp  ! Van Albada, Van Leer, SUPERBEE
+            end if
+        end if
+
+        ! Initialize counts: viscous fluids, surface-tension interfaces, curvature interfaces
         Re_size = 0
         Re_size_max = 0
 
@@ -1254,6 +1266,7 @@ contains
             $:GPU_UPDATE(device='[num_fluids, num_dims, viscous, num_vels, nb, muscl_lim]')
         #:endif
 
+        $:GPU_UPDATE(device='[muscl_eps]')
         $:GPU_UPDATE(device='[dir_idx, dir_flg, dir_idx_tau]')
 
         $:GPU_UPDATE(device='[relax, relax_model, palpha_eps, ptgalpha_eps]')

docs/res/simulations/x.jpg

@@ -169,27 +169,26 @@ contains
                                     slope = 0._wp
 
                                     if (muscl_lim == 1) then  ! minmod
-                                        if (slopeL*slopeR > 1e-9_wp) then
+                                        if (slopeL*slopeR > muscl_eps) then
                                             slope = min(abs(slopeL), abs(slopeR))
                                         end if
                                         if (slopeL < 0._wp) slope = -slope
                                     else if (muscl_lim == 2) then  ! MC
-                                        if (slopeL*slopeR > 1e-9_wp) then
+                                        if (slopeL*slopeR > muscl_eps) then
                                             slope = min(2._wp*abs(slopeL), 2._wp*abs(slopeR))
                                             slope = min(slope, 5e-1_wp*(abs(slopeL) + abs(slopeR)))
                                         end if
                                         if (slopeL < 0._wp) slope = -slope
                                     else if (muscl_lim == 3) then  ! Van Albada
-                                        if (abs(slopeL) > 1e-6_wp .and. abs(slopeR) > 1e-6_wp .and. abs(slopeL + slopeR) &
-                                            & > 1e-6_wp .and. slopeL*slopeR > 1e-6_wp) then
+                                        if (slopeL*slopeR > muscl_eps) then
                                             slope = ((slopeL + slopeR)*slopeL*slopeR)/(slopeL**2._wp + slopeR**2._wp)
                                         end if
                                     else if (muscl_lim == 4) then  ! Van Leer
-                                        if (abs(slopeL + slopeR) > 1.e-6_wp .and. slopeL*slopeR > 1.e-6_wp) then
+                                        if (slopeL*slopeR > muscl_eps) then
                                             slope = 2._wp*slopeL*slopeR/(slopeL + slopeR)
                                         end if
                                     else if (muscl_lim == 5) then  ! SUPERBEE
-                                        if (slopeL*slopeR > 1e-6_wp) then
+                                        if (slopeL*slopeR > muscl_eps) then
                                             slope = -1._wp*min(-min(2._wp*abs(slopeL), abs(slopeR)), -min(abs(slopeL), &
                                                                & 2._wp*abs(slopeR)))
                                         end if

src/simulation/m_global_parameters.fpp

@@ -217,7 +217,7 @@ contains
         type(scalar_field), dimension(sys_size), intent(inout) :: q_cons_vf
         integer, intent(in)                                    :: j, k, l
         #:if not MFC_CASE_OPTIMIZATION and USING_AMD
-            real(wp), dimension(2) :: alpha_rho, alpha
+            real(wp), dimension(3) :: alpha_rho, alpha
         #:else
             real(wp), dimension(num_fluids) :: alpha_rho, alpha
         #:endif

src/simulation/m_muscl.fpp

@@ -88,7 +88,7 @@ contains
 
         namelist /user_inputs/ case_dir, run_time_info, m, n, p, dt, &
             t_step_start, t_step_stop, t_step_save, t_step_print, &
-            model_eqns, mpp_lim, time_stepper, weno_eps, &
+            model_eqns, mpp_lim, time_stepper, weno_eps, muscl_eps, &
             rdma_mpi, teno_CT, mp_weno, weno_avg, &
             riemann_solver, low_Mach, wave_speeds, avg_state, &
             bc_x, bc_y, bc_z, &