Onset of dynamic stall of tubercled wings

Zhao, Ming; Xu, Lianchao; Tang, Zhizhong; Zhang, Xiaolu; Zhao, Bo; Liu, Zhengxian; Wei, Zhaoyu

doi:10.1063/5.0057730

Cited by 16 publications

(3 citation statements)

References 38 publications

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“…At the large AOA, the visualization image of the oil flow in the leading-edge region of the WLE airfoil indicates that the WLE will generate vortices in the spanwise direction. Previous studies [17,21,42] also showed that the pressure distribution differed at the spreading nodular crest and trough, resulting in different influences of the vortices on the flow field at the crest and trough of the WLEs. The velocity distribution of the flow field at the WLEs crest and WLEs trough is different, resulting from the streamwise vortices' influence on the spreading direction.…”

Section: Discussion On Control Mechanism Of Wlesmentioning

confidence: 95%

Experimental Investigation of the Effect of Bio-Inspired Wavy Leading-Edges on Aerodynamic Performance and Flow Topologies of the Airfoil

Du,

Jiang,

Yang

et al. 2024

Aerospace

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The characteristic of delayed airfoil stalls caused by the bio-inspired Wavy Leading-Edges (WLEs) has attracted extensive attention. This paper investigated the effect of WLEs on the aerodynamic performance and flow topologies of the airfoil through wind tunnel experiments, while also discussing the flow control mechanism of WLEs. The result shows that, at small Angle of Attack (AOA), the flow through the WLEs exhibits periodic and symmetrical characteristics, where flow vortices upwash at the trough and downwash at the crest, resulting in flow from the crest to the trough. Upwash leads to the formation of a localized three-dimensional laminar separation bubble (LSB) structure at the leading edge of the trough section. At large AOA after baseline airfoil stall, the flow on the airfoil surface of WLEs presents a two-period pattern along the spanwise direction, and the separation zone and the attachment zone appear alternately, indicating that the control effect of delayed stall is accomplished by reducing the separation zone on the airfoil surface. The alternating occurrence of the separation and attachment zones is the result of intricate interactions among flows passing through multiple WLEs. This interaction causes the convergence of high-momentum attached airflows on both sides, thereby constraining the spread of the separation from the leading edge and enabling the re-attachment of separated air. The research results of this paper provide a reference for researchers to reveal the flow control mechanism of WLEs more comprehensively.

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Section: Discussion On Control Mechanism Of Wlesmentioning

confidence: 95%

Experimental Investigation of the Effect of Bio-Inspired Wavy Leading-Edges on Aerodynamic Performance and Flow Topologies of the Airfoil

Du,

Jiang,

Yang

et al. 2024

Aerospace

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“…14 Another popular strategy is the use of deployable actuators such as trailing edge flaps, [15][16][17] leading-edge minitabs, 18 and vortex generators. 19 Nature-inspired concepts, such as leading-edge tubercles 20 and bio-inspired alula, 21,22 have also been explored for altering the dynamics of the LEV and the process of dynamic stall.…”

Section: Introductionmentioning

confidence: 99%

Lift tailoring on unsteady airfoils with leading-edge vortex shedding using an inverse aerodynamic approach

Suresh Babu,

Narsipur,

Gopalarathnam

2024

Physics of Fluids

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In this paper, we present a physics-informed approach to tailor the lift profile of an unsteady airfoil through the execution of an appropriate maneuver. In previous research, a low-order aerodynamic model based on the unsteady thin airfoil theory was developed for predicting the flowfield and loads on airfoils undergoing arbitrary motions. The theory was phenomenologically augmented using the concept of leading edge suction parameter (LESP) to incorporate the capability to predict intermittent leading edge vortex (LEV) shedding. The criticality of LESP was used to predict the onset and termination of LEV shedding and thus model the effect of LEVs on the flowfield and loads for a prescribed motion. In the current work, an inverse aerodynamic formulation is developed based on this framework for tackling the inverse problem: to obtain the motion kinematics required for generating a prescribed lift profile for an airfoil operating in the dynamic-stall regime. The LEV-modeling capability of the aerodynamic model enables the motion-design algorithm to take into account the effect of complex phenomena, such as dynamic stall and LEV shedding, which are not taken into account in previous research approaches. Several case studies are presented to demonstrate various scenarios such as lift tracking using pitching and heaving motions, lift cancellation during unsteady motion, and the generation of a given lift profile using two equivalent motions. The kinematic profiles generated by the inverse formulation are also simulated using a high-fidelity unsteady computational fluid dynamics solver to validate the predictions.

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“…The spatial computational domains for resolving the dynamic stall are discretized into up to 10 6 grid nodes to obtain sufficient accuracy. 25,26 Therefore, CFD models are high order, requiring considerably computational cost. In addition, the major issue of large-scale complex flow modeling is the reduction of the computational cost while preserving numerical accuracy.…”

Section: Introductionmentioning

confidence: 99%

Low order modeling of dynamic stall using vortex particle method and dynamic mode decomposition

Nguyen

Duong

Trinh

et al. 2023

International Journal of Micro Air Vehicles

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Low order modelings are performed in this paper, including iterative Brinkman penalized vortex method (IBVM) and data-driven dynamic mode decomposition (DMD) for dynamic stall study of symmetric airfoil. The data are extracted from IBVM as input for flow field reconstruction using combinations of DMD dominant modes, representing extracted flow features. The primary mode together with its harmonics, and the mean mode are termed to be dominant for the airfoil wake duplication at fixed angles of attack ([Formula: see text]) ranging from [Formula: see text] to [Formula: see text]. For the dynamic stall duplication, at small and large pitching amplitudes, the nearfield and farfield vorticty contours from the DMD generally agree well with those from the IBVM. In addition, the lift coefficient from the DMD collapses well with that from the IBVM and the experiment.

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Onset of dynamic stall of tubercled wings

Cited by 16 publications

References 38 publications

Experimental Investigation of the Effect of Bio-Inspired Wavy Leading-Edges on Aerodynamic Performance and Flow Topologies of the Airfoil

Experimental Investigation of the Effect of Bio-Inspired Wavy Leading-Edges on Aerodynamic Performance and Flow Topologies of the Airfoil

Lift tailoring on unsteady airfoils with leading-edge vortex shedding using an inverse aerodynamic approach

Low order modeling of dynamic stall using vortex particle method and dynamic mode decomposition

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