rtx-cfd: the deformed cylinder–flag outline's edge fractions come from the UNDEFORMED straight edge (x_tip_ref), so the patch topology is the mesh family's and not the deformation's — the P5-1 gate run died at the first bend with set_mesh refusing 143 → 144 wall cells; the P5-0 test now gates ns across amplitudes (143 at −80 / +40 / +80 mm)

Co-Authored-By: Claude Fable 5.1 <[email protected]>
Claude-Session: https://claude.ai/code/session_0116sg1Qz1gMv9hdcKP1XUam

crates/specialized/rtx-fsi/tests/fsi2_harness/overset.rs

@@ -24,7 +24,7 @@ use rtx_cfd::{CfdConfig, CfdResult};
 use rtx_fea::mesh::{Mesh, NodeId};
 use rtx_fsi::{FluidFace, WettedSurface};
 
-use super::{flag_mesh, inflow_for, BenchmarkCase, Interface, H, L, NU_F, RHO_F};
+use super::{flag_mesh, inflow_for, BenchmarkCase, Interface, FLAG_X1, H, L, NU_F, RHO_F};
 
 const CYL_CENTRE: [f64; 2] = [0.2, 0.2];
 const CYL_R: f64 = 0.05;
@@ -157,6 +157,7 @@ impl OversetFluid {
             CYL_R,
             FLAG_T,
             &interface.edges(&zero_d),
+            FLAG_X1,
             h,
             FILLET,
             6.0 * h,
@@ -246,6 +247,7 @@ impl OversetFluid {
             CYL_R,
             FLAG_T,
             &self.interface.edges(d),
+            FLAG_X1,
             self.h,
             FILLET,
             6.0 * self.h,