Experimental Study of Splitter Plates for Use with Semispan Wing Models

Diebold, Jeff M.; Woodard, Brian S.; Monastero, Marianne C.; Bragg, Michael B.

doi:10.2514/6.2015-1227

Cited by 6 publications

(3 citation statements)

References 7 publications

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“…Finally, a series of experiments was also conducted with a pair of rectangular splitter plates that were installed on the airfoil model to reduce the three-dimensional effects of the flow at the model tips. These plates were fabricated with a dimension of 0.686 m by 0.457 m, following the recommendations of Diebold et al, [34] and were installed at a distance of approximately 50 mm from the floor and ceiling of the test section.…”

Section: Airfoil Installationmentioning

confidence: 99%

Unsteady Flow Physics of Airfoil Dynamic Stall

Gupta

Ansell²

2019

AIAA Journal

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A series of wind tunnel experiments were conducted on an NACA 0012 airfoil undergoing a linear pitch ramp maneuver at a fixed dimensionless pitch rate of Ω + = 0.05 and across three transitional Reynolds numbers, Re c = 0.2 × 10 6 , Re c = 0.5 × 10 6 , and Re c = 1.0 × 10 6. The primary objectives of these experiments were to perform a detailed analysis of the flow evolution, with particular emphasis on the underlying physical mechanisms, and to extract the dominant scales associated with the flow perturbations, for a canonical dynamic stall process. A series of unsteady surface pressure measurements, with a high sampling frequency, were acquired in order to investigate the time-dependent behavior of the flow in the immediate vicinity of the airfoil. These surface pressure measurements were used to identify the region of boundary layer transition during the initial stages of the dynamic stall process. A spatially-contracting laminar separation bubble was also identified near the airfoil leading edge from the characteristic pressure plateau in the surface pressure distribution. The dominant frequencies associated with the laminar separation bubble were extracted using a continuous wavelet transform technique. These frequencies were observed to span a wide range of chordbased Strouhal numbers between St = 50 and St = 105, at Re c = 0.5 × 10 6. The off-body flow evolution was inferred and described using a combination of surface pressure measurements and time-resolved particle image velocimetry. For Re c = 0.2 × 10 6 and Re c = 0.5 × 10 6 , the dynamic stall vortex was observed to emerge from a collective interaction of the discrete vortices that were ejected from the leading edge of the airfoil. At Re c = 1.0 × 10 6 , however, the near-wall vortices were observed to amalgamate into two regions, forming a distinct primary and a secondary coherent structure. After formation, these two structures were observed to interact with each other, following a co-rotating vortex merging process and resulting in the emergence of a single, coherent dynamic stall vortex. The process of emergence of the dynamic stall vortex at Re c = 1.0 × 10 6 , observed from the present experiments, is therefore quite distinct from the classical understanding of the dynamic stall vortex formation, which was observed at the lower Reynolds numbers. The time-dependent spectra of the velocity field were calculated using a combination of empirical mode decomposition and Hilbert transformation. From the velocity spectra, the fluctuations in the flow were observed to attain an amplified state during the initial ejection of vorticity from the leading-edge region of

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Section: Airfoil Installationmentioning

confidence: 99%

Unsteady Flow Physics of Airfoil Dynamic Stall

Gupta

Ansell²

2019

AIAA Journal

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“…The splitter plate eliminates the boundary layer growth on the wind tunnel floor. The splitter plate was modeled according to the guidelines established by Diebold et al (2015). The splitter plate and fairings were combined in a single part, eliminating the need for fasteners.…”

Section: Wind Tunnel and Set-upmentioning

confidence: 99%

Analysis of additively manufactured flexible wing model

Fernandes,

Hu,

Wang

et al. 2023

RPJ

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Purpose This paper aims to assess the feasibility of additively manufactured wind tunnel models. The additively manufactured model was used to validate a computational framework allowing the evaluation of the performance of five wing models. Design/methodology/approach An optimized fighter wing was additively manufactured and tested in a low-speed wind tunnel to obtain the aerodynamic coefficients and deflections at different speeds and angles of attack. The flexible wing model with optimized curvilinear spars and ribs was used to validate a finite element framework that was used to study the aeroelastic performance of five wing models. As a computationally efficient optimization method, homogenization-based topology optimization was used to generate four different lattice internal structures for the wing in this study. The efficiency of the spline-based optimization used for the spar-rib model and the lattice-based optimization used for the other four wings were compared. Findings The aerodynamic loads and displacements obtained experimentally and computationally were in good agreement, proving that additive manufacture can be used to create complex accurate models. The study also shows the efficiency of the homogenization-based topology optimization framework in generating designs with superior stiffness. Originality/value To the best of the authors’ knowledge, this is the first time a wing model with curvilinear spars and ribs was additively manufactured as a single piece and tested in a wind tunnel. This research also demonstrates the efficiency of homogenization-based topology optimization in generating enhanced models of different complexity.

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“…The model has a splitter plate to mitigate boundary layer effects. 24 Both a CAD model and the model installed in the WSU wind tunnel test section are shown in Fig. 1.…”

Section: A Wing Modelmentioning

confidence: 99%

The Application of a Five-Hole Probe Wake-Survey Technique to the Study of Swept Wing Icing Aerodynamics

Lum

Sandhu

Diebold

et al. 2017

9th AIAA Atmospheric and Space Environments Conference

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This paper describes a wake survey system used to improve the understanding of the underlying flowfield and aerodynamics of a swept wing with ice accretions. This system allows the rapid collection and analysis of large amounts of flowfield data by utilizing an array of five-hole probes on a precisely controlled traverse arm. Flowfield structure on the surface of the wing is acquired using an oil flow visualization technique and correlated to the associated wake survey. This method allows quantitative calculations such as spanwise lift and drag to be compared with qualitative measurements and observations to enhance the understanding of the aerodynamics of wings containing ice accretions. Wind tunnel tests for a range of configurations are presented and analyzed in this paper. Results based on this wake survey method are compared with traditional measurement techniques such as force balance measurements to assess their accuracy.

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Experimental Study of Splitter Plates for Use with Semispan Wing Models

Cited by 6 publications

References 7 publications

Unsteady Flow Physics of Airfoil Dynamic Stall

Unsteady Flow Physics of Airfoil Dynamic Stall

Analysis of additively manufactured flexible wing model

The Application of a Five-Hole Probe Wake-Survey Technique to the Study of Swept Wing Icing Aerodynamics

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