Assessment of current rotor design comparison practices based on high-fidelity CFD methods

Abstract

This paper provides an assessment of current rotor design comparison practices. First, the employed CFD method is validated for a number of rotor designs and is shown to achieve accurate performance predictions in hover and high-speed forward flight. Based on CFD results, a detailed investigation is performed in terms of comparing different rotor designs. The CFD analysis highlighted the need of high fidelity methods due to the subtle aerodynamics involved in advanced planforms. Nevertheless, the paper suggests that the correct basis for comparison in terms of performance metrics must be used to inform decisions about the suitability of the rotor blades designs for specific applications. In particular, when comparing blades of advanced planforms, direct torque and thrust comparisons are better than the commonly used lift to drag ratio and figure of merit.

A data-driven reduced-order model for rotor optimization

“…Specifically for wind turbine applications, significant progress has been made by the National Renewable Energy Laboratory (NREL) in streamlining the progress of completing large-eddy simulation (LES) atmospheric boundary layer simulations coupled with wind turbines through their OpenFAST tool sets (Jonkman, 2013). Through leveraging such tool sets, studies of isolated rotors have been shown to be capable of resolving flow fields relevant for performance and loads of isolated rotors in hover/forward flight (Fitzgibbon et al, 2020), during rotorcraft pitch-up maneuvers (Abhishek et al, 2011), and in rotorship wake interactions (Crozon et al, 2018). Many recent publications have demonstrated the feasibility of deploying such modeling techniques for wind turbine applications.…”

A Data-Driven Reduced Order Model for Rotor Optimization

“…have been developed to help streamline the process of CFD simulation of rotors. Large Eddy Simulation (LES) (Smagorinsky, 1963) and Detached Eddy Simulations (DES) (Spalart, 1997) studies of isolated rotors have shown to be capable of resolving flow fields relevant for performance and loads of isolated rotors in hover/forward flight (Fitzgibbon et al, 2020), during rotorcraft pitch up maneuvers (Abhishek et al, 2011), and rotor-ship wake interactions (Crozon et al, 2018). In a recent publication by Sood et al (2022), high-fidelity LES simulations were completed for five different inflow conditions of the Lillgrund wind farm.…”