Change to multiphase hybrid coupling - nodal projection

amr-wind/equation_systems/vof/volume_fractions.H

@@ -493,10 +493,11 @@ AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE bool interface_band(
     const int j,
     const int k,
     amrex::Array4<amrex::Real const> const& volfrac,
-    const int n_band = 1) noexcept
+    const int n_band = 1,
+    const amrex::Real tiny = 1e-12) noexcept
 {
     // n_band must be <= number of vof ghost cells (3)
-    constexpr amrex::Real tiny = 1e-12;
+
     // Check if near interface
     amrex::Real VOF_max = 0.0;
     amrex::Real VOF_min = 1.0;

amr-wind/overset/OversetOps.cpp

@@ -82,6 +82,13 @@ void OversetOps::pre_advance_work()
             // Update pressure gradient using sharpened pressure field
             update_gradp();
         }
+        if (!m_disable_nodal_proj) {
+            // Calculate vof-dependent node mask
+            const auto& iblank = m_sim_ptr->repo().get_int_field("iblank_node");
+            const auto& vof = m_sim_ptr->repo().get_field("vof");
+            auto& mask = m_sim_ptr->repo().get_int_field("mask_node");
+            overset_ops::iblank_to_mask_vof(iblank, vof, mask);
+        }
     }
 
     // If pressure gradient will be replaced, store current pressure gradient

amr-wind/overset/overset_ops_routines.H

@@ -5,9 +5,13 @@
 #include "AMReX_MultiFab.H"
 #include "amr-wind/equation_systems/vof/volume_fractions.H"
 #include "amr-wind/overset/overset_ops_K.H"
+#include "amr-wind/core/FieldRepo.H"
 
 namespace amr_wind::overset_ops {
 
+void iblank_to_mask_vof(
+    const IntField& iblank, const Field& vof, IntField& maskf);
+
 // Populate approximate signed distance function using vof field
 void populate_psi(
     amrex::MultiFab& mf_psi,

amr-wind/overset/overset_ops_routines.cpp

@@ -1,6 +1,59 @@
 #include "amr-wind/overset/overset_ops_routines.H"
 
 namespace amr_wind::overset_ops {
+
+void iblank_to_mask_vof(
+    const IntField& iblank, const Field& voff, IntField& maskf)
+{
+    const auto& nlevels = iblank.repo().mesh().finestLevel() + 1;
+    constexpr amrex::Real band_tol = 1e-4;
+
+    for (int lev = 0; lev < nlevels; ++lev) {
+        const auto& ibl = iblank(lev);
+        const auto& vof = voff(lev);
+        auto& mask = maskf(lev);
+
+        const auto& ibarrs = ibl.const_arrays();
+        const auto& vofarrs = vof.const_arrays();
+        const auto& marrs = mask.arrays();
+        amrex::ParallelFor(
+            ibl, ibl.n_grow,
+            [=] AMREX_GPU_DEVICE(int nbx, int i, int j, int k) noexcept {
+                // Default is masking all 0 and -1 iblanks
+                marrs[nbx](i, j, k) = amrex::max(ibarrs[nbx](i, j, k), 0);
+                // Check cells neighboring node for being near interface
+                bool near_interface = false;
+                for (int ii = i - 1; ii < i + 1; ii++) {
+                    for (int jj = j - 1; jj < j + 1; jj++) {
+                        for (int kk = k - 1; kk < k + 1; kk++) {
+                            near_interface =
+                                near_interface ||
+                                amr_wind::multiphase::interface_band(
+                                    ii, jj, kk, vofarrs[nbx], 1, band_tol);
+                        }
+                    }
+                }
+                // Check nodes neighboring node for being near solid
+                bool near_solid = false;
+                for (int ii = i - 1; ii < i + 2; ii++) {
+                    for (int jj = j - 1; jj < j + 2; jj++) {
+                        for (int kk = k - 1; kk < k + 2; kk++) {
+                            near_solid = ibarrs[nbx](ii, jj, kk) == 0
+                                             ? true
+                                             : near_solid;
+                        }
+                    }
+                }
+                // Do mask -1 cells near interface
+                if (ibarrs[nbx](i, j, k) == -1 &&
+                    (near_interface && !near_solid)) {
+                    marrs[nbx](i, j, k) = 1;
+                }
+            });
+    }
+    amrex::Gpu::synchronize();
+}
+
 // Populate approximate signed distance function using vof field
 void populate_psi(
     amrex::MultiFab& mf_psi,
@@ -502,7 +555,7 @@ void replace_gradp(
     amrex::ParallelFor(
         mf_gp, mf_gp.n_grow,
         [=] AMREX_GPU_DEVICE(int nbx, int i, int j, int k) noexcept {
-            if (iblank[nbx](i, j, k) == -1) {
+            if (iblank[nbx](i, j, k) <= 0) {
                 gp[nbx](i, j, k, 0) = gp0[nbx](i, j, k, 0);
                 gp[nbx](i, j, k, 1) = gp0[nbx](i, j, k, 1);
                 gp[nbx](i, j, k, 2) = gp0[nbx](i, j, k, 2);