Modification of Leishman–Beddoes model incorporating with a new trailing-edge vortex model

Abstract

The Leishman-Beddoes (L-B) model for airfoil dynamic stall is widely used in both helicopter rotor and wind turbine aerodynamics because it has fewer parameters and specific physical conceptions. However, in some cases of airfoil dynamic stall, the differences between the calculated results and experimental data are obvious, especially for the reattachment of airfoil dynamic stall. In order to observe the characteristics of dynamic stall about rotor airfoil, some dynamic stall experiments by PIV technology and CFD simulations based on RANS equations are accomplished. As a result, a trailing-edge vortex is observed which is not considered in the present L-B models. To consider the effect of this trailing-edge vortex on the unsteady aerodynamic characteristic, a new model of trailing-edge vortex is presented in this paper. In this method, the normal force induced by trailing-edge vortex is calculated by a similar methodology as leadingedge vortex, and the moment is modified due to the trailing-edge vortex. Consequently, the aerodynamic loads calculated by the modified L-B model at different reduced frequencies, Mach numbers, and airfoils are closer to the experimental data in the reattachment of dynamic stall. Therefore, it is demonstrated that the new trailing-edge vortex model further reflects the essence of trailing-edge vortex during the process of dynamic stall.

Amplitude Control of Stall-Induced Nonlinear Aeroelastic System Based on Iterative Learning Control and Unified Pitch Motion

“…For instance, an improved trailing-edge vortex model in the reattachment of a dynamic stall was applied to observe the characteristics of a dynamic stall about a rotor blade, with the aerodynamic loads estimated by using the modified B-L model. The dynamic stall responses were tested by using Particle Image Velocimetry technology, and were completely consistent with the theoretical simulation results that reflect the essence of the trailing-edge vortex which occurred in the stall state [6]. Furthermore, it is also an important subject to study the different states and control methods of mild stall and deep stall as well as post-stall phenomena.…”

An improved second-order dynamic stall model for wind turbine airfoils

“…Although many studies have been dedicated to dynamic stall modeling (Gupta and Leishman, 2006;Larsen et al, 2007;Adema et al, 2020;Elgammi and Sant, 2016;Wang and Zhao, 2015;Sheng et al, 2006;Galbraith, 2007;Sheng et al, 2008), engineering calculations in the industry are still relying on the very basic classical dynamic stall models such as the Leishman-Beddoes and Snel models. The reason is the simplicity to tune in the models for different airfoils and for different flow conditions.…”

An improved second order dynamic stall model for wind turbine airfoils

“…Then, the models compute the dynamic force difference required for the reconstruction process. Although many attempts have been dedicated for dynamic stall modeling (Gupta and Leishman, 2006;Larsen et al, 2007;Adema et al, 2019;Elgammi and Sant, 2016;Wang and Zhao, 2015;Sheng et al, 2006;Galbraith, 2007;Sheng et al, 2008), engineering calculations in industry are still relying on the very basic classical dynamic stall models such as the Leishman-Beddoes and Snel models. The reason is the simplicity to tune in the models for different airfoils and for different flow conditions.…”