Numerical studies of undulation control on dynamic stall for reverse flows

• 作 者: Biao Wang Jian Liu Yunjun Yang Zhixiang Xiao
• 机 构: School of Aerospace Engineering,Tsinghua University,Beijing 100084,China“,”China Aerodynamics Resear
• 出 处: 力学学报（英文版）
• 发表日期: 2020年2期
• 关键词: DDES-AC model Dynamic stall Reverse flow Undulating leading edge Flow control

The delayed detached-eddy simulation with adaptive coefficient (DDES-AC) method is used to simulate the baseline and leading-edge undulation control of dynamic stall for the reverse flow past a finite-span wing with NACA0012 airfoil. The numerical results of the baseline configuration are compared with available measurements. DDES and DDES-AC perform differently when predicting the primary and secondary dynamic stalls. Overall, DDES-AC performs better owing to the decrease of grey area between the strong shear layer and the fully three-dimensional separated flow. Moreover, the effects of the undulating leading-edge on the forces, lift gradients, and instantaneous flow structures are explored. Compared with the uncontrolled case, the lift gradient in the primary dynamic stall is reduced from 18.4 to 8.5, and the secondary dynamic stall disappears. Therefore, periodic unsteady air-loads are also reduced. Additionally, the control mechanism of the wavy leading edge (WLE) is also investigated by comparison with the straight leading edge (SLE). No sudden breakdown of strong vortices is the main cause for WLE control.