Visualization and PIV study of wing-tip vortices for three different tip configurations

Sohn, Myung-Hwan; Chang, Jo Won

doi:10.1016/j.ast.2011.02.005

Cited by 33 publications

(18 citation statements)

References 10 publications

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“…Several studies have been reported in literature, which return the qualitative inspection of the vortex structure (Sohn and Chang 2012). Other works have quantitatively revealed complex flow features such as secondary vortices around delta wings, vortex breakdown and shear layer instabilities (Furman and Breitsamter 2013;Wang et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Helium-filled soap bubbles for vortex core velocimetry

2017

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Section: Introductionmentioning

confidence: 99%

Helium-filled soap bubbles for vortex core velocimetry

2017

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“…The secondary and tertiary vortices merges into the primary vortex within one chord from the trailing edge of the wing and the form an axialsymmetric vortical structure with axial velocity higher then the freestream (jet-like). As Freymuth et al [3] stated, flow visualization seems to be the best approach to obtain clues about complex vortical structures and many studies on this phenomenon begins with flow visualizations [2,4,5]. Since the squared tip is a source of singularities in theoretical or numerical analysis, the study of flow over such geometry is particularly significant [6].…”

Section: Introductionmentioning

confidence: 99%

Vortex formation on squared and rounded tip

Giuni

Green

2013

Aerospace Science and Technology

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The vortical flow originated from the tip of a NACA 0012 rectangular wing is described in its initial formation and development over a rounded and a squared tip. Smoke visualizations show the rolling-up kinematic and evolution of the vortical systems moving the plane towards the trailing edge. The presence of intense secondary vortices affects the primary vortex unsteadiness and shape during the formation and in the early wake. Stereoscopic Particle Image Velocimetry is used to describe vorticity, axial velocity and turbulent kinetic energy distributions of the vortex during the formation and in the early wake at different angles of attack of the wing. The rolling-up of the vorticity sheet around the vortex system is strongly influenced by the vortex shape and the intensity of secondary vortices. Turbulence coming from secondary structures and shear layers is wrapped into the roll-up of the vortex and high levels of turbulence are measured in the vortex core. However, a laminar vortex core is observed for the lower angle of attack in the early wake. Comparing the meandering of the vortex for the two wingtip geometries, two different sources of the vortex fluctuation in the wake are identified: the interaction of secondary vortices moving around the primary vortex and the rolling-up of the vorticity sheet. Lastly, measurements in the wake of the wing at zero incidence are also presented showing a distinctive counter rotating vortex pair.

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“…Sohn [49] has done experimental studies with NACA airfoils by using the smoke-wire technique to produce visible streak lines and images captured and analyzed by PIV methods. The free-stream velocity was 26.0 m/s, and the corresponding Reynolds number was 4.12 Â 10 5 .…”

Section: Ldv Measurementmentioning

confidence: 99%