Capturing wake capture: a 2D numerical investigation into wing–wake interaction aerodynamics

Li, Hao; Nabawy, Mostafa R. A.

doi:10.1088/1748-3190/ac98e5

Cited by 6 publications

(9 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It occurs due to the flow induced by two counter-rotating forefoil wake vortices during pronation, represented by an arrow in figure 5(a). Such type of flow phenomena, where the foil interacts with its own wake vortices generated during previous stroke, is known as 'wake capture' or 'wing-wake interaction' [33][34][35]. This causes an early shedding of the forefoil TEV (figure 5 Figure 6 shows that thrust generation (negative C H ) mostly occurs during upstroke, whereas downstroke plays a smaller role.…”

Section: Resultsmentioning

confidence: 99%

Effect of stroke plane inclination on the hovering aerodynamic performance of tandem flapping foils

Tiwari,

Chandel

2024

Bioinspir. Biomim.

View full text Add to dashboard Cite

The four-winged form of dragonfly and damselfly allows them to fly with great agility and endurance, which is accomplished by independently controlling the kinematics of each wing. In this study, we have performed numerical simulations of two tandem airfoils oscillating along an inclined stroke plane at Re=157. We investigated the effect of stroke plane angle (β) of forefoil and hindfoil on the aerodynamic performance of dragonflies (or damselflies) hovering flight. The simulations are carried out for parallel and non-parallel stroke planes of forefoil and hindfoil oscillating with three phase differences i.e., ϕ=0^o, 90^o and 180^o. For parallel stroke planes, the results show that total lift increases with β whereas total thrust decreases. Also, the total lift as well as thrust reduces with an increase in ϕ. The forefoil performance is affected by the flow induced by hindfoil leading-edge vortices (LEVs), and the hindfoil interaction with forefoil wake vortices significantly affects the hindfoil performance. The results show that non-parallel stroke planes have detrimental effects on the total lift for ϕ=0^o and 90^o. However, for ϕ=180^o, lift augmentation of 46% is obtained in the case where the forefoil stroke plane angle is smaller than the hindfoil. The results obtained during this investigation can help in optimizing the wing kinematics during the Micro-Air-Vehicles (MAVs) development.

show abstract

Section: Resultsmentioning

confidence: 99%

Effect of stroke plane inclination on the hovering aerodynamic performance of tandem flapping foils

Tiwari,

Chandel

2024

Bioinspir. Biomim.

View full text Add to dashboard Cite

show abstract

“…Reynolds number is known to affect the shape of vortex structures in a profound way, which would in turn affect the amplitude of the wake capture force peaks. The recent study of Li & Nabawy [36] has shown that the wake capture effect becomes stronger as the Reynolds number increases over ). Finally, the use of different switching gains to fit different experimental results should not be seen as a major concern as it was shown that the way the model input parameters affect the wake capture results is independent from the value of the switching gain.…”

Section: Limitations Of the Current Modelmentioning

confidence: 98%

“…I believe it is useful to stop here and consider the aspect ratio effect on wake capture lift, in light of some of the recent findings within the flapping wing aerodynamics field [35,36]. In particular, a recent experimental campaign from Addo-Akoto et al [35] considered the wing aspect ratio influence on wake capture aerodynamics.…”

Section: Sensitivity To Input Parametersmentioning

confidence: 99%

“…Note that recent experimental and numerical studies [37][38][39] have confirmed that wing tip stall occurs for revolving/flapping wings at radial wing locations greater than 3.5-5 times the mean geometric chord (measured from the centre of rotation). This takes me to a recent numerical study by Li and Nabawy [36], which conducted a comprehensive numerical analysis on wake capture aerodynamics of two-dimensional wings.…”

Section: Sensitivity To Input Parametersmentioning

confidence: 99%

See 1 more Smart Citation

A simple model of wake capture aerodynamics

Nabawy

2023

J. R. Soc. Interface.

Self Cite

View full text Add to dashboard Cite

Flapping wings may encounter or ‘capture’ the wake from previous half-stroke, leading to local changes in the instantaneous aerodynamic force on the wing at the start of each half-stroke. In this paper, I developed a simple approach to integrating prediction of these wake capture effects into existing analytical quasi-steady models for hovering insect flapping flight. The local wake flow field is modelled as an additional induced velocity component normal to the stroke plane of the flapping motion that is blended/switched in at the start of each half-stroke. Comparison of model results against experimental data in the literature shows satisfactory agreement in predicting the wake capture lift and drag variations for eight different test cases. Sensitivity analysis shows that the form of the translation velocity time history has a significant effect on the magnitude of wake capture forces. Profiles that retain high translational velocity right up to stroke reversal evoke a much larger effect from wake capture compared with sinusoidal. This result is significant because while constant flapping translation velocity profiles can be generated in the laboratory, the very high accelerations required near stroke reversals incur high mechanical cost that prevents practical adoption in nature or engineered flapping flight vehicles.

show abstract

“…In contrast, the LEV of a 2-D aerofoil always sheds in a translating motion. This discrepancy in the spatial-temporal status of the LEV can affect the wing–wake interaction because the LEV attachment status has been proven to determine the specific contribution of inter-vortex jet and single-vortex suction mechanisms (Li & Nabawy 2022). Specifically, how the unsteady evolution of an outboard LEV affects the wing–wake interaction is still unclear.…”

Section: Introductionmentioning

confidence: 99%

Coexistence of dual wing–wake interaction mechanisms during the rapid rotation of flapping wings

Chen,

2024

J. Fluid Mech.

View full text Add to dashboard Cite

Insects flip their wings around each stroke reversal and may enhance lift in the early stage of a half-stroke. The possible lift-enhancing mechanism of this rapid wing rotation and its strong connection with wake vortices are still underexplored, especially when unsteady leading-edge vortex (LEV) behaviours occur. Here, we numerically studied the lift generation and underlying vorticity dynamics during the rapid rotation of a low aspect ratio flapping wing at a Reynolds number ( ${\textit {Re}}$ ) of 1500. Our findings prove that when the outboard LEV breaks down, an advanced rotation can still enhance the lift in the early stage of a half-stroke, which originates from an interaction with the breakdown vortex in the outboard region. This interaction, named the breakdown-vortex jet mechanism, results in a jet and thus a higher pressure on the upwind surface, including a stronger wingtip suction force on the leeward surface. Although the stable LEV within the mid-span retains its growth and location during an advanced rotation, it can be detrimental to lift enhancement as it moves underneath the wing. Therefore, for a flapping wing at ${\textit {Re}}\sim 10^3$ , the interactions with stable and breakdown leading-edge vortices lead to the single-vortex suction and breakdown-vortex jet mechanisms, respectively. In other words, the contribution of wing–wake interaction depends on the spanwise location. The current work also implies the importance of wing kinematics to this wing–wake interaction in flapping wings, and provides an alternative perspective for understanding this complex flow phenomenon at ${\textit {Re}}\sim 10^3$ .

show abstract

Capturing wake capture: a 2D numerical investigation into wing–wake interaction aerodynamics

Cited by 6 publications

References 57 publications

Effect of stroke plane inclination on the hovering aerodynamic performance of tandem flapping foils

Effect of stroke plane inclination on the hovering aerodynamic performance of tandem flapping foils

A simple model of wake capture aerodynamics

Coexistence of dual wing–wake interaction mechanisms during the rapid rotation of flapping wings

Contact Info

Product

Resources

About