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Assessment of Delayed Detached-Eddy Simulation of Dynamic Stall on a Rotor

  • Johannes LetzgusEmail author
  • Pascal Weihing
  • Manuel Keßler
  • Ewald Krämer
Conference paper
Part of the Notes on Numerical Fluid Mechanics and Multidisciplinary Design book series (NNFM, volume 143)

Abstract

High-fidelity unsteady Reynolds–averaged Navier–Stokes (URANS) and Menter-SST delayed detached-eddy simulations (DDES) of dynamic stall on a rotor with cyclic pitch control are presented and compared to experimental surface pressures and particle-image-velocimetry (PIV) data. Before the dynamic-stall event, the DDES suffers from modeled-stress depletion (MSD) leading to grid-induced separation (GIS) due to a breakdown of the boundary-layer shielding function \(f_d\). Combined with the “grey-area” problem, this leads to severe erroneous load peaks. After dynamic stall, flow is completely separated and only DDES shows realistic small-scale, incoherent vortical structures. Two approaches are investigated to eliminate MSD/GIS: Firstly, increasing the empirical constant \(C_{d1}\) of the \(f_d\) function to 30 basically eliminates GIS. Secondly, a non-local, grid-independent vorticity-integrated algebraic DES, which replaces the \(f_d\) function, is introduced that provides robust boundary-layer shielding and enables the LES mode in case of massive flow separation.

Notes

Acknowledgements

This work was funded by DFG grant Untersuchung der dreidimensionalen dynamischen Strömungsablösung an Rotorblättern (investigation of three-dimensional dynamic stall on rotor blades). Computing resources were provided by the High Performance Computing Centre Stuttgart (HLRS) under project HELISIM.

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Copyright information

© Springer Nature Switzerland AG 2020

Authors and Affiliations

  • Johannes Letzgus
    • 1
    Email author
  • Pascal Weihing
    • 1
  • Manuel Keßler
    • 1
  • Ewald Krämer
    • 1
  1. 1.Institute of Aerodynamics and Gas DynamicsUniversity of StuttgartStuttgartGermany

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