embedded3 S2-6: the three closures default ON (oblique distance, transverse centroid correction, fine floor) — RTX_E3_WALL_DISTANCE=face RTX_E3_DIFFUSION_TRANSVERSE=0 RTX_E3_DISTANCE_FLOOR=coarse reproduce every earlier record digit for digit (checked: DFG 2D ny 62 host); DFG 2D D/h 30 c_D -0.19 % -> -0.01 %, 3D ny 124 6.1750 / 0.00844 / 0.1692 inside the bar on both routes

Co-Authored-By: Claude Fable 5.1 <[email protected]>

crates/specialized/rtx-cfd/src/solvers/incompressible/embedded3/step/mod.rs

@@ -100,7 +100,7 @@ pub struct Parameters {
     /// α)|n_t|` (`n_t` the wall normal's part in the face plane) instead
     /// of `φ + ½h(1 − α)`, which over-reads the distance on oblique walls
     /// by `½h(1 − α)(1 − |n_t|)` at every h (S2-5). `Parameters::default()`
-    /// reads `RTX_E3_WALL_DISTANCE=oblique` (default: the recorded form).
+    /// is ON since S2-6 (`RTX_E3_WALL_DISTANCE=face` restores the recorded form).
     pub wall_distance_oblique: bool,
     /// The transverse part of the centroid diffusion (S2-6): two neighbour
     /// faces with different apertures have open-part centroids offset
@@ -108,11 +108,11 @@ pub struct Parameters {
     /// carries `∇u · Δs_⊥` — a first-order wall position on oblique walls
     /// (≈ 0.1 h inside the body). Removed with the faces' own wall-normal
     /// gradients `(u − U_b)/d_f`, in the cross AND the own direction.
-    /// Needs `diffusion_centroid`. `RTX_E3_DIFFUSION_TRANSVERSE=1`.
+    /// Needs `diffusion_centroid`. ON since S2-6 (`RTX_E3_DIFFUSION_TRANSVERSE=0`).
     pub diffusion_transverse: bool,
     /// The wall-distance floor at 0.01 of the smallest spacing instead of
     /// 0.05: the coarse floor doubles the distance of faces with α < 0.1
-    /// (the flat wall's θ 0.95 excess, S2-6). `RTX_E3_DISTANCE_FLOOR=fine`.
+    /// (the flat wall's θ 0.95 excess). ON since S2-6 (`RTX_E3_DISTANCE_FLOOR=coarse`).
     pub distance_floor_fine: bool,
     /// The diffusive exchange of a fluid face with a SOLID neighbour face
     /// over the axis distance to the wall, `δ = min(h, d_f/|n_d|)`, and
@@ -155,11 +155,15 @@ impl Default for Parameters {
                 .ok()
                 .and_then(|v| v.parse().ok())
                 .unwrap_or(1),
+            // The three S2-6 closures are ON by default; `RTX_E3_WALL_DISTANCE=face`,
+            // `RTX_E3_DIFFUSION_TRANSVERSE=0` and `RTX_E3_DISTANCE_FLOOR=coarse`
+            // together reproduce every record before S2-6 digit for digit.
             wall_distance_oblique: std::env::var("RTX_E3_WALL_DISTANCE")
-                .is_ok_and(|v| v == "oblique"),
+                .map_or(true, |v| v != "face"),
             diffusion_transverse: std::env::var("RTX_E3_DIFFUSION_TRANSVERSE")
-                .is_ok_and(|v| v == "1"),
-            distance_floor_fine: std::env::var("RTX_E3_DISTANCE_FLOOR").is_ok_and(|v| v == "fine"),
+                .map_or(true, |v| v != "0"),
+            distance_floor_fine: std::env::var("RTX_E3_DISTANCE_FLOOR")
+                .map_or(true, |v| v != "coarse"),
             wall_exchange_axis: std::env::var("RTX_E3_WALL_EXCHANGE").is_ok_and(|v| v == "axis"),
             pressure_centroid: std::env::var("RTX_E3_PRESSURE_CENTROID").is_ok_and(|v| v == "1"),
             // ON by default since S2-5 (`=0` reproduces the records before it).