Assessing relevant roughness scales for accurate predictions of iced airfoils in both glaze and rime conditions

ORAL

Abstract

Accurately predicting aircraft performance degradation due to icing is crucial for certifying next-generation aircraft designs. Current ice accretion models often simulate ice growth as two-dimensional and lacking small scale distributed roughness observed in ice accretion experiments. To evaluate the impact of local roughness on aerodynamic loads of iced airfoils, we conducted RANS and wall modeled LES analyses on a hierarchy of filtered ice shapes under rime and glaze conditions. Baseline shapes of realistic ice were derived from laser scans of ice formed on a NACA23012 airfoil at the NASA Glenn IRT. We generated increasingly smoothed ice shapes using a volume-preserving Laplacian smoothing algorithm to the limit of two-dimensional shapes like those generated from ice accretion models. For glaze ice with horn-like structures, filtered roughness scales minimally affect lift, drag, and pressure profiles. However, for rime ice conditions, removing the smallest roughness scales significantly alters the lift curve to the extent of mispredicting the stall condition. This highlights the need for either artificially generated roughness in rime-iced environments or improved sub-grid roughness models.

*We acknowledge the funding support from Stanford University's Center for Turbulence Research Summer Program, NASA's TTT Program, the Boeing Company, the DoD SMART Fellowship, the Woodruff School of Mechanical Engineering at Georgia Institute of Technology, and the European Union under grant agreement No 101072551.

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Presenters

  • Brett Bornhoft

    • Air Force Research Laboratory
    • Stanford University

Authors

  • Tommaso Bellosta

    • Politecnico di Milano

  • Alessandro Donizetti

    • Politecnico di Milano

  • Federico Zabaleta

    • Center for Turbulence Research, Stanford University

  • Brett Bornhoft

    • Air Force Research Laboratory
    • Stanford University

  • Suhas Jain

    • Woodruff School of Mechanical Engineering, Georgia Institute of Technology, USA. Center for Turbulence Research, Stanford Universty, USA
    • Georgia Institute of Technology, Flow Physics and Computational Sciences Lab
    • Woodruff School of Mechanical Engineering, Georgia Tech
    • Flow Physics and Computational Science Lab, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA
    • Woodruff School of Mechanical Engineering, Georgia Institute of Technology; Center for Turbulence Research, Stanford University
    • George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA

  • Sanjeeb T Bose

    • Cadence Design Systems, Inc and Institute for Computational and Mathematical Engineering, Stanford University
    • Cascade Technologies, Inc.

  • Alberto Guardone

    • Politecnico di Milano