Flow Characteristics over Double Delta Wings at Low Reynolds Numbers

Karasu, İlyas; Durhasan, Tahir

doi:10.1061/(asce)as.1943-5525.0001155

Cited by 6 publications

(3 citation statements)

References 25 publications

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“…Interestingly, two counter-rotating vortices are observed at X/C = 1.0, an elongated one in size as the leading-edge vortex and another one small in size as the trailing-edge vortex on either side of the flying wing. Various authors reported presence of multiple vortices on the surface of a delta/double delta wing [58][59][60][61]. However, these works on a delta/double delta wing indicate that the trailing edge does not play any role in the generation of these multiple vortices.…”

Section: Mean Vortical Flow Field In the Crossflow Planementioning

confidence: 98%

An experimental investigation on the aerodynamic characteristics and vortex dynamics of a flying wing

Kumar,

Mandal,

Poddar

2024

Aeronaut. j.

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In this paper, we present a detailed experimental investigation mainly on the vortical flow fields and the associated vortex breakdown phenomena over a non-slender flying wing (sweep angle, ${\rm{\Lambda }}$ = 53°). In the process, the aerodynamic coefficients were also determined using a six-component force balance. Surface oil flow visualisation, surface pressure measurements and particle image velocimetry (PIV) measurements, in various crossflow planes and in a longitudinal plane passing through the leading-edge vortex core, were carried out at various Reynolds numbers to understand the flow field over the non-slender flying wing. Aerodynamic characteristics of the flying wing show local peaks and valleys in the pitching moment coefficient. The surface flow visualisation reveals that the nonlinearity of the pitching moment curve is due to the complex nature of vortical flow structures. The flow visualisation also demonstrates the presence of a wave-like surface pattern, and its size is found to reduce with increasing Reynolds numbers. The present PIV measurements confirm that this wave-like surface pattern is associated with vortex breakdown phenomena. These measurements also reveal that the vortex breakdown has not reached the apex of the wing, even at post-stall angle-of-attack. For pre-stall ( $\alpha $ = 20°) flow regimes, it is observed that the location of the vortex breakdown moves downstream as the Reynolds number increases, but this influence is minimised at near-stall ( $\alpha $ = 25°) and post-stall ( $\alpha $ = 30°) flow regimes. Reconstructed velocity field using the first 10 dominant proper orthogonal decomposition (POD) modes reveals that the nature of the vortex breakdown over the flying wing is a spiral-type vortex breakdown.

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Section: Mean Vortical Flow Field In the Crossflow Planementioning

confidence: 98%

An experimental investigation on the aerodynamic characteristics and vortex dynamics of a flying wing

Kumar,

Mandal,

Poddar

2024

Aeronaut. j.

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“…It is noteworthy that after exceeding the critical angle of attack, in the case of the FF aircraft, the slowest C N growth slows down. This means that the FlatFlyer has very good aerodynamic characteristics after a stall (after exceeding the critical angle of attack) [26]. It should be assumed that the plane will be falling slightly and that the altitude loss needed to get it out of the stall will be relatively small.…”

Section: Comparison Of the Basic Coefficients Of The Flatflyer Model With Other Flying Solutionsmentioning

confidence: 99%

A Flow Analysis Using a Water Tunnel of an Innovative Unmanned Aerial Vehicle

Lis

Januszko

Dobrocinski³

2021

Applied Sciences

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The purpose of this article is to present and discuss the results of a non-standard unnamed aerial vehicle construction with a constant cross-section square-shaped avionic profile. Based on the model’s in-air observed maneuverability, the research of avionic construction behavior was carried out in a water tunnel. The results show the model’s specific lift capabilities in comparison to classical avionic constructions. The characteristic results of the lift coefficient showed that the unmanned aerial vehicle presents favorable features than classic avionic constructions. The model was created with the prospect of using it in the future for dual-use purposes, where unmanned aerial vehicles are currently experiencing very rapid development. When creating the prototype, the focus was on low production cost, as well as convenience in operation. The development of this type of breakthrough avionic solution, which shows extraordinary maneuverability, may contribute to increasing the popularity and, above all, the availability of unmanned aerial vehicles for the largest possible group of recipients because of high avionic properties in relation to the technical construction complexity.

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“…For decades, the flow around the wing has had a wide range of applications because of practical significance (Lee et al , 2018; Qi et al , 2014). Experimental research on the delta wing has been an important method (Ghimire and Bailey, 2017; Karasu and Durhasan, 2020; Marzanek and Rival, 2019) and numerical simulation of flow around delta wing has been developed (Li et al , 2020). The influence of slip boundary on the National Advisory Committee for Aeronautics wing has been studied and the drag can be effectively reduced by the slip boundary (Wang et al , 2018b), but the flow around delta wing with fluid slip has not been simulated numerically.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on slip flow using the discrete unified gas-kinetic scheme

Guo

Hou

Guan

et al. 2021

HFF

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Purpose This paper aims to explore the mechanism of the slip phenomenon at macro/micro scales, and analyze the effect of slip on fluid flow and heat transfer, to reduce drag and enhance heat transfer. Design/methodology/approach The improved tangential momentum accommodation coefficient scheme incorporated with Navier’s slip model is introduced to the discrete unified gas kinetic scheme as a slip boundary condition. Numerical tests are simulated using the D2Q9 model with a code written in C++. Findings Velocity contour with slip at high Re is similar to that without slip at low Re. For flow around a square cylinder, the drag is reduced effectively and the vortex shedding frequency is reduced. For flow around a delta wing, drag is reduced and lift is increased significantly. For Cu/water nanofluid in a channel with surface mounted blocks, drag can be reduced greatly by slip and the highest value of drag reduction (DR) (67.63%) can be obtained. The highest value of the increase in averaged Nu (11.78%) is obtained by slip at Re = 40 with volume fraction φ=0.01, which shows that super-hydrophobic surface can enhance heat transfer by slip. Originality/value The present study introduces and proposes an effective and superior method for the numerical simulation of fluid/nanofluid slip flow, which has active guidance meaning and applied value to the engineering practice of DR, heat transfer, flow control and performance improvement.

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Flow Characteristics over Double Delta Wings at Low Reynolds Numbers

Cited by 6 publications

References 25 publications

An experimental investigation on the aerodynamic characteristics and vortex dynamics of a flying wing

An experimental investigation on the aerodynamic characteristics and vortex dynamics of a flying wing

A Flow Analysis Using a Water Tunnel of an Innovative Unmanned Aerial Vehicle

Numerical study on slip flow using the discrete unified gas-kinetic scheme

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