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CHT Boundary Layers

Video topic: near-wall/boundary-layer meshing at CHT interfaces — why it's the single biggest lever on h accuracy, and how much resolution is actually enough.

Talking points:

  • y+ under 1 — boundary-layer meshing at a CHT interface makes or breaks convective h accuracy; under-resolving the near-wall region is the most common way to get a plausible-looking but wrong answer. (Ansys FENSAP-ICE)
  • How many layers through a thin solid wall — 3–5 element layers, not one; a single-layer solid mesh under-resolves the conduction gradient through thin walls. (Ansys FENSAP-ICE)
  • Inflation layers at the solid-fluid interface — hex/prism elements in thin near-wall regions, and why sharp edges/thin walls cause numerical instability if not handled. (Neural Concept)
  • Coarse near-wall meshing → poor gradient capture — insufficient boundary-layer/inflation resolution at the interface directly degrades temperature-gradient accuracy, not just velocity. (Ansys Innovation Space / CFX forum)
  • Mesh orthogonality companion mistake — bad orthogonality angle at a fluid-solid interface (rule of thumb: keep under 10°) causes unphysical hot spots even when near-wall resolution looks fine on paper. (Ansys forum)

Sources:

  • Ansys [UNAVAILABLE -- was: https://trafolo.atlassian.net/wiki/spaces/Documentat/pages/581271553/Ansys] — FENSAP-ICE (y+, layer count) and Innovation Space forum (orthogonality, near-wall resolution) entries
  • Neural Concept — interface meshing entry