Improvements on the Beddoes-Leishman dynamic stall model for low speed applications

Flexible wing and rotor blade designs operating at low Mach number (M <= 0.3) environments may undergo or need to avoid stall flutter and, therefore, accurately predict dynamic stall airloads. At the preliminary stage, aeroelastic calculations routines place a limit on computational expenses and demand low-order models. However, the semi-empirical dynamic stall models used for such purposes still present some flaws for low freestream speeds, especially under stall onset and light stall conditions. Given that, the present paper proposes improvements for the Beddoes-Leishman model. Building upon past modifications for the low-speed dynamic stall, several modeling strategies for the onset of stall, reattachment, and vortex-shedding processes are introduced. These enhancements are extensively validated with previously available experimental data for the symmetric NACA 0012 and cambered AMES-01 airfoils, showing superior results over the base model for virtually all conditions tested, albeit requiring up to 40% longer computational time. (C) 2021 Elsevier Ltd. All rights reserved.