embedded3 S2-3d: face-momentum unsteady term for the box (Mask::box_momentum_rates, Solver::previous_apertures); falsifier prints the residual against it

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

crates/specialized/rtx-cfd/tests/embedded3_falsifier.rs

@@ -210,6 +210,8 @@ struct Record {
     fy_lag: f64,
     /// The force the momentum equation applied (shear on u*, exchange on uⁿ).
     fy_applied: f64,
+    /// The box route with the scheme's own (face control volume) momentum rate.
+    fy_cv_faces: f64,
     fresh: usize,
     skipped: usize,
     p_far: f64,
@@ -320,6 +322,15 @@ fn run(scheme: WallScheme, moving: bool, dt: f64, t_end: f64) -> Run {
             false,
             solver.previous_volumes(),
         )[1] / lz;
+        let (rate_faces, rate_cells) = mask.box_momentum_rates(
+            &field,
+            dt,
+            RHO,
+            (margin, N - margin, margin, N - margin, 0, nz),
+            solver.previous_apertures(),
+            solver.previous_volumes(),
+        );
+        let fy_cv_faces = fy_cv + (rate_cells[1] - rate_faces[1]) / lz;
         let p_far = field.p[g.cell(kp, jp, ip)];
         let mut ke = 0.0;
         for k in 0..nz {
@@ -357,6 +368,7 @@ fn run(scheme: WallScheme, moving: bool, dt: f64, t_end: f64) -> Run {
             fy_floor,
             fy_lag,
             fy_applied,
+            fy_cv_faces,
             fresh: result.fresh_cells,
             skipped,
             p_far,
@@ -370,13 +382,15 @@ fn run(scheme: WallScheme, moving: bool, dt: f64, t_end: f64) -> Run {
         };
         let mean = |f: &dyn Fn(&Record) -> f64| records.iter().map(f).sum::<f64>() / n;
         println!(
-            "    route residual (wall − box) RMS {:.3e} → with the floor source {:.3e}, with the closure lag {:.3e}, both {:.3e}, APPLIED form {:.3e} (mean {:+.3e}); means wall {:+.3e} box {:+.3e} floor {:+.3e} lag {:+.3e}; box RMS {:.3e}",
+            "    route residual (wall − box) RMS {:.3e} → with the floor source {:.3e}, with the closure lag {:.3e}, both {:.3e}, APPLIED form {:.3e} (mean {:+.3e}), against the FACE-momentum box {:.3e} (its mean {:+.3e}); means wall {:+.3e} box {:+.3e} floor {:+.3e} lag {:+.3e}; box RMS {:.3e}",
             rms(&|r| r.fy - r.fy_cv),
             rms(&|r| r.fy + r.fy_floor - r.fy_cv),
             rms(&|r| r.fy + r.fy_lag - r.fy_cv),
             rms(&|r| r.fy + r.fy_floor + r.fy_lag - r.fy_cv),
             rms(&|r| r.fy_applied - r.fy_cv),
             mean(&|r| r.fy_applied),
+            rms(&|r| r.fy - r.fy_cv_faces),
+            mean(&|r| r.fy_cv_faces),
             mean(&|r| r.fy),
             mean(&|r| r.fy_cv),
             mean(&|r| r.fy_floor),