Seunghyun Joo

Seunghyun Joo

Research Associate at Seoul National University | Looking for a PhD position

pyhyp-rotor-overset-generator: Open-Source Overset Mesh Generation for Rotors

DOI GitHub

🔍 Project Overview

Open-source toolchain that turns a plain-text per-section planform table (r/R, chord, twist about 0.25c, LE position, airfoil) into a complete overset (chimera) mesh system for rotor CFD:

  • Blade component mesh — a watertight structured surface marched into a wall-resolved (y+ ≈ 1) hexahedral boundary layer with pyHyp (typical mean non-orthogonality ~2°)
  • Full rotor — automatic replication of the blade volume about the rotor axis (nBlades)
  • Background mesh — structured Cartesian grid with a rotor refinement box (spacing given in tip chords), growing geometrically outward
  • Output is plain PLOT3D (+ ParaView VTK export), so the meshes are solver-agnostic.

⚙️ Key Features

Non-degenerate watertight tip-cap topology

pyHyp’s normal-consistency check rejects any collapsed cap edge, so blade tips are closed with Coons-TFI caps whose four edges are exact point subsets of the blade perimeter (leading-edge nose arc / surfaces / blunt-TE seal) — the marcher sees only supported node topologies. Optional capDome rounds the tip cap.

Robust real-airfoil support

Selig and Lednicer coordinate files (e.g. straight from the UIUC database) are auto-detected, resampled with a cubic spline in √x space and noise-filtered, with the leading-edge point spacing automatically scaled to the estimated nose radius.

Overset-aware spacing control

autoMatch solves the geometric-series design problem so the outermost wall-normal blade cell lands just below the background refinement spacing — the classic overset donor-quality rule — validated against marched volumes to within ~2%.

📦 Examples & Validation

Four fully-worked examples ship with the repository — the Caradonna–Tung hover rotor, a tapered/swept blade with an airfoil transition, a NACA 23012 blade, and a UH-60-style blade using the real Sikorsky SC1095 section — all marching to completion with final pyHyp Min Quality ≈ 0.42.

🔗 Links