Flow Structure on Nonslender Delta Wing: Reynolds Number Dependence and Flow Control

Zharfa, Mohammadreza; Ozturk, Ilhan; Yavuz, Mehmet Metin

doi:10.2514/1.j054495

Cited by 18 publications

(4 citation statements)

References 20 publications

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“…Earlier vortex breakdown was discovered for this wing configuration due to non-slender wing characteristics. The present finding also supported the previous study on non-slender delta wing [5,7,10,21] which concluded that the vortex breakdown moved upstream as α increased. In Figure 6(c), it is noticeable that the suction peak of the primary vortex increases when the Reynolds number is increased.…”

Section: Clean Wing Configuration (No Propeller)supporting

confidence: 92%

Effects of the Propeller Advance Ratio on Delta Wing UAV Leading Edge Vortex

Kasim

Segard

Mat

et al. 2019

IJAME

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Delta wing is a triangular-shaped platform that can be applied into the unmanned aerial vehicle (UAV) or drone applications. However, the flow above the delta wing is governed by complex leading-edge vortex structures which result in complicated aerodynamics behaviour. At higher angles of attack, the vortex burst can take place when the swirling flow is unable to sustain the adverse pressure gradient. More studies are needed to understand these vortex phenomena. This paper addresses an experimental study of active flow control called propeller on a generic 55° swept angle sharp-edged delta wing model. In this experiment, a propeller was placed at two different locations. The first location was at the apex of the wing while the second position was at the rear of the wing. The experiments were conducted in a 1.5 × 2.0 m2 closed-loop wind tunnel facility at Universiti Teknologi Malaysia. The freestream velocities were set at 20 m/s and 25 m/s. The research consisted of an intensive surface pressure measurement above the wing surface to investigate the effects of rotating propeller towards the leading-edge vortex. The experiments were divided into four configurations. The clean wing configuration was performed without the propeller and followed by pusher-propeller configuration using 10-inch 9-inch propellers. The final configuration was the tractor-propeller with a 10-inch propeller. The results emphasise the influences of the propeller size and its location corresponding to vortex properties above the delta-winged UAV model. The findings had indicated that the vortex peak is increased when the propeller is installed for both pusher and tractor configurations. The results also indicate that the pressure coefficient is increased when the propeller advance ratio increases.

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Section: Clean Wing Configuration (No Propeller)supporting

confidence: 92%

Effects of the Propeller Advance Ratio on Delta Wing UAV Leading Edge Vortex

Kasim

Segard

Mat

et al. 2019

IJAME

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“…Details on LSM are available in previous works along with the fundamental equations [18,19]. FSI technique [25] is often applied where a deformation in the solid structure is expected due to its interaction with the fluid flow [26,27] (for more details, see [28]). FSI incorporates an ALE method to take into account the mesh deformation caused by the movement and the impact of droplet and particle [29], and thereby, droplet and particle become freely moving meshes.…”

Section: Methodsmentioning

confidence: 99%

Building pathways to full encapsulation processes

Shamsipour

Manshadi

Khojasteh

et al. 2021

ICLASS

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Encapsulation, i.e. the coating of tiny solid or liquid particles in a liquid film, has received a growing interest among scholars due to its practical applications, especially in food and pharmaceutical industries. Encapsulation technology is used in coating and controlling drug delivery by protecting the active agents from environmental pressures (e.g., heat, oxygen) and unsought colours/odours. In practice, when dealing with solid particles, this process occurs through impacting liquid droplets of the coating material upon the agent particles. While, in reality, droplet and particle can freely move before and after the collision, a vast majority of the previous efforts to characterize drop-particle impact outcomes have considered that one of the two components is stationary. This study numerically investigates the head-on collisions between freely moving droplet of a glycerine-water solution or synthetic fluids, and freely moving dry spherical particles. In order to achieve this results, a novel 2D axisymmetric Level Set simulation includes fluid-structure interaction (FSI) and an arbitrary Lagrangian-Eulerian (ALE) technique The relative impact velocity and drop-to-particle density ratio are varied across the simulation cases to indicate the importance of variations in momentum. These preliminary results indicate that optimising the momentum is a key factor in achieving a full and stable encapsulation, requiring further research.

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“…Figure 13(a, e, c, and g) shows that the minimum suction pressure, i.e. minimum mean −C p values, occurs near the reattachment location, as indicated by the velocity vectors of the flow field, similar to a swept delta wing [62], whereas the peak suction pressure (mean −C p ) occurs near the vortex core, albeit with slight offset towards the leading edge. On the other hand, Fig.…”

Section: Surface Pressure Measurementsmentioning

confidence: 97%

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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Flow Structure on Nonslender Delta Wing: Reynolds Number Dependence and Flow Control

Cited by 18 publications

References 20 publications

Effects of the Propeller Advance Ratio on Delta Wing UAV Leading Edge Vortex

Effects of the Propeller Advance Ratio on Delta Wing UAV Leading Edge Vortex

Building pathways to full encapsulation processes

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

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