Skin friction fields on delta wings

Woodiga, Sudesh; Liu, Tianshu

doi:10.1007/s00348-009-0686-6

Cited by 27 publications

(11 citation statements)

References 26 publications

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“…Liu et al (24) and Woodinga and Liu. (25) have investigated the flow over a 65°delta wing at a Reynolds number based on root chord of 4.1E4 in a water tunnel and in air at 4.4E5. The objective of their investigations was to demonstrate techniques for the extraction of skin friction fields, from surface luminescent dye visualizations in water and Global Luminescent Oil Film (GLOF) in air.…”

Section: Qualitative Comparisons With Other Datamentioning

confidence: 99%

A computational study of laminar-flow secondary separation on a slender delta wing

Jones¹,

Riley

2018

Aeronaut. j.

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The laminar flow over a slender delta wing at incidence has been extensively studied both experimentally and theoretically using vortex sheet methods. These vortex sheet methods have generally been successful apart from the prediction of the secondary boundary-layer separation induced by the primary vortex. This paper revisits the problem using computational fluid dynamics (CFD) and focusses on the effects of the secondary flow separation. The modelling approach is briefly summarised, and the results are compared with flow measurements and results from vortex sheet methods. The computations show very good agreement with measurements for the surface pressures and total head contours. The results help to understand the complex structure of the leading edge vortex flow, and the associated secondary separation of the boundary layer. They indicate that inviscid mechanisms dominate the larger scale features, and highlight a possible mechanism for the development of an instability in the leading edge vortex sheet.

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Section: Qualitative Comparisons With Other Datamentioning

confidence: 99%

A computational study of laminar-flow secondary separation on a slender delta wing

Jones¹,

Riley

2018

Aeronaut. j.

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“…High-resolution skin friction fields on the delta wings were obtained by using the GLOF skin friction meter. 31–33 This technique is based on surface luminescent oil visualization that represents the oil-film thickness distribution. The evolution equation relating the luminescent intensity to skin friction is derived in the image plane, which has the same mathematical form as the physics-based optical flow equation.…”

Section: Experimental Technique and Setupmentioning

confidence: 99%

“…8,9,17–20 The global luminescent oil-film (GLOF) technique allows mapping of topological features such as singular points, reattachment and separation lines, and other subtle features associated with vortex bursting and vortex interactions. 31,32 The previous study focused on the changes in the topological structures of skin friction fields for a 65° delta wing and a 76/40° double-delta wing with the juncture fillets as AoA was increased. The effects of the juncture fillets on vortex breakdown and performance characteristics of a 76/40° double-delta wing were also evaluated.…”

Section: Introductionmentioning

confidence: 99%

Effects of pitch, yaw, and roll on delta wing skin friction topology

Woodiga

Liu

Ramasamy

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part G:

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High-resolution skin friction fields in separated flows over a 65° delta wing and a 76/40° double-delta wing with different junction fillets are obtained by using quantitative global skin friction diagnostics based on luminescent oil visualizations. The topological features such as separation and attachment lines on these delta wings are identified, and the effects of the pitch, yaw, and roll angles on the skin friction topology are studied systematically. The topological consistency of the measured skin friction fields on the delta wings is examined by using the Poincare–Bendixson index formula.

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“…These two tornado vortices occupy almost 50 % of the cavity floor when a store is placed in the cavity. The fluorescence-oil-flow visualization technique uses light with a specific wavelength and energy to irradiate the oil pigment, which can better reveal the details of wall flow structures (Woodiga & Liu 2009; Chen et al. 2017).…”

Section: Introductionmentioning

confidence: 99%

Evolution of tornado-like vortices in three-dimensional compressible rectangular cavity flows

Luo

Tian

et al. 2023

J. Fluid Mech.

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The spatial structure and time evolution of tornado-like vortices in a three-dimensional cavity are studied by topological analysis and numerical simulation. The topology theory of the unsteady vortex in the rectangular coordinate system (Zhang, Zhang & Shu, J. Fluid Mech., vol. 639, 2009, pp. 343–372) is generalized to the curvilinear coordinate system. Two functions $\lambda (q_1,t)$ and $q(q_1,t)$ are obtained to determine the topology structure of the sectional streamline pattern in the cross-section perpendicular to the vortex axis and the meridional plane, respectively. The spiral direction of the sectional streamlines in the cross-section perpendicular to the vortex axis depends on the sign of $\lambda (q_1,t)$ . The types of critical points in the meridional plane depend on the sign of $q(q_1,t)$ . The relation between the critical points of the streamline pattern in the meridional plane and that in the cross-section perpendicular to the vortex axis is set up. The flow in a three-dimensional rectangular cavity is numerically simulated by solving the three-dimensional Navier–Stokes equations using high-order numerical methods. The spatial structures and the time evolutions of the tornado-like vortices in the cavity are analysed with our topology theory. Both the bubble type and spiral type of vortex breakdown are observed. They have a close relationship with the vortex structure in the cross-section perpendicular to the vortex axis. The bubble-type breakdown has a conical core and the core is non-axisymmetric in the sense of topology. A criterion for the bubble type and the spiral type based on the spatial structure characteristic of the two breakdown types is provided.

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Skin friction fields on delta wings

Cited by 27 publications

References 26 publications

A computational study of laminar-flow secondary separation on a slender delta wing

A computational study of laminar-flow secondary separation on a slender delta wing

Effects of pitch, yaw, and roll on delta wing skin friction topology

Evolution of tornado-like vortices in three-dimensional compressible rectangular cavity flows

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