Design of an Infinite-Swept-Wing Glove for In-Flight Discrete-Roughness-Element Experiment

Tufts, Matthew W.; Reed, Helen L.; Saric, William S.

doi:10.2514/1.c032490

Cited by 9 publications

(4 citation statements)

References 26 publications

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“…The work in this paper considers the boundary layer over a swept NLF wing (G-IIB, TAMU-0706 wing glove) designed by Tufts et al 19 at Texas A & M University. The design of TAMU-0706 wing glove has improved upon that of Belisle et al 11 with a truly uniform flow in the spanwise direction and substantially improved stability characteristics.…”

Section: Flow Conditions and Numerical Methodologymentioning

confidence: 99%

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Direct Numerical Simulation of Receptivity to Roughness in a Swept-Wing Boundary Layer at High Reynolds Numbers

Nicholson

Zhang

Duan

et al. 2018

2018 Fluid Dynamics Conference

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Direct numerical simulations (DNS) are performed to examine the receptivity to roughness in a spatially developing three-dimensional boundary layer over an infinite-swept natural-laminar-flow wing at a freestream Mach number of 0.75 and a chord Reynolds number of approximately 25 million based on the long, swept chord. Stationary crossflow disturbances are excited by applying either critically spaced discrete cylinders of micron size or naturally occurring distributed roughness in the leading-edge region. The DNS data show that the spanwise spectral content of the excited crossflow disturbances is highly dependent upon the shape of roughness elements, and the initial growth of the crossflow structures is a nonlinear function of the element height. The linear growth rate of the excited crossflow disturbances predicted by DNS shows good agreement with linear parabolized stability equations. The receptivity study lays the foundation for investigating the stabilization of the naturally most unstable steady crossflow mode by using spanwise periodic DREs.

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Section: Flow Conditions and Numerical Methodologymentioning

confidence: 99%

“…Figure 5. (a) Surface pressure coefficient Cp obtained from the DNS and RANS for the infiniteswept wing (without roughness) in comparison with the results in Tufts et al19 The inset provides a zoomed-in view of all Cp curves over the leading edge. (b) Density contours of the baseflow obtained from the RANS calculation of the entire wing and the current DNS.…”

mentioning

confidence: 99%

Direct Numerical Simulation of Receptivity to Roughness in a Swept-Wing Boundary Layer at High Reynolds Numbers

Nicholson

Zhang

Duan

et al. 2018

2018 Fluid Dynamics Conference

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“…T he Class-Shape Transformation (CST) parametrization method 1, 2, 3 has become an increasingly popular method for creating analytical representations of the surface coordinates of various components of aerospace vehicles. 4,5,6,7 CST parametrization can be used to represent a wide variety of two-and threedimensional shapes with a modest number of parameters, and it provides built-in design variables for use in shape optimization. The use of analytical functions means that the surface representation is smooth and continuous to as fine a degree as desired, without the need for interpolation between discrete points.…”

Section: Nomenclaturementioning

confidence: 99%

Three-Dimensional Piecewise-Continuous Class-Shape Transformation of Wings

Olson

2015

16th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference

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Class-Shape Transformation (CST) is a popular method for creating analytical representations of the surface coordinates of various components of aerospace vehicles. A wide variety of two-and three-dimensional shapes can be represented analytically using only a modest number of parameters, and the surface representation is smooth and continuous to as fine a degree as desired. This paper expands upon the original two-dimensional representation of airfoils to develop a generalized three-dimensional CST parametrization scheme that is suitable for a wider range of aircraft wings than previous formulations, including wings with significant non-planar shapes such as blended winglets and box wings. The method uses individual functions for the spanwise variation of airfoil shape, chord, thickness, twist, and reference axis coordinates to build up the complete wing shape. An alternative formulation parametrizes the slopes of the reference axis coordinates in order to relate the spanwise variation to the tangents of the sweep and dihedral angles. Also discussed are methods for fitting existing wing surface coordinates, including the use of piecewise equations to handle discontinuities, and mathematical formulations of geometric continuity constraints. A subsonic transport wing model is used as an example problem to illustrate the application of the methodology and to quantify the effects of piecewise representation and curvature constraints.

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“…the critical wavelength mode) from growing, hence delaying the turbulent onset. Appropriately spanwise spaced roughness have been demonstrated to be capable of delivering extended laminar flow both in laboratory experiments and flight tests (Crawford et al, 2015;Tufts et al, 2014). A recent experiment also examined the effect of DREs in a moderate-level disturbance facility (Saeed et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

On the effect of discrete roughness on crossflow instability in very low turbulence environment

Placidi

Bokhorst

Atkin

2016

8th AIAA Flow Control Conference

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This is the published version of the paper.This version of the publication may differ from the final published version. Wind tunnel experiments were conducted in a low-turbulence environment (T u < 0.006%) on the stability of 3D boundary layers. The effect of two different distributions of discrete roughness elements (DREs) on crossflow vortices disturbances and their growth was evaluated. As previously reported, DREs are found to be an effective tool in modulating the behaviour of crossflow modes. However, the effect of 24µm DREs was found to be weaker than previously thought, possibly due to the low level of environmental disturbances herewith. Preliminary results suggest that together with the height of the DREs and their spanwise spacing, their physical distribution across the surface also intimately affects the stability of 3D boundary layers. Finally, crossflow vortices are tracked along the chord of the model and their merging is captured. This phenomena is accompanied by a change in the critical wavelength of the dominant mode. Permanent repository link

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Design of an Infinite-Swept-Wing Glove for In-Flight Discrete-Roughness-Element Experiment

Cited by 9 publications

References 26 publications

Direct Numerical Simulation of Receptivity to Roughness in a Swept-Wing Boundary Layer at High Reynolds Numbers

Direct Numerical Simulation of Receptivity to Roughness in a Swept-Wing Boundary Layer at High Reynolds Numbers

Three-Dimensional Piecewise-Continuous Class-Shape Transformation of Wings

On the effect of discrete roughness on crossflow instability in very low turbulence environment

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