Aerodynamic Design and Assessment of Modular Test Section Walls for CFD Validation in Hybrid Anechoic Wind Tunnels

Duetsch-Patel, Julie E.; Vishwanathan, Vidya; Minionis, Jared B.; Totten, E. J.; Gargiulo, Aldo; Fritsch, Daniel J.; Szőke, Máté; Borgoltz, Aurélien; Roy, Christopher J.; Lowe, K. Todd; Devenport, William J.

doi:10.2514/6.2020-2214

Cited by 15 publications

(2 citation statements)

References 7 publications

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“…The flow is tripped in the contraction, 3.54 m upstream of the test section coordinate origin (see Figure 1), such that the measured flow is fully turbulent and free from any transitional effects. Further information regarding the specifics of the wind tunnel facility and experiment configurations can be found in [12][13][14]. The coordinate system is set such that x is streamwise, y is wall-normal, and z is spanwise with corresponding u, v, w velocity components.…”

Section: Experimental Facilities and Methods 21 Facilitymentioning

confidence: 99%

Spatial Resolution Limitations of Particle Image Velocimetry in High Reynolds Number Turbulent Boundary Layers

Vishwanathan

Fritsch

Devenport

et al. 2022

Preprint

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Particle image velocimetry (PIV) has become a standard technique in turbulence experiments for its non-intrusive ability to simultaneously measure multiple points in a flow field. However, inherent volume averaging of the interrogation windows as well as fixed limitations of camera spatial resolution and related hardware set the minimum and maximum scales of structures that can be resolved with this measurement technique. Resolution limitations present themselves as an attenuation of the measured turbulence statistics, seen particularly in the Reynolds wall-normal stress components. This experimental study investigates the impact of hardware-level resolution limitations on the resolved turbulence statistics of PIV measurements made of both rough and smooth wall turbulent boundary layers influenced by external pressure gradients. Velocity fields are measured with PIV using two lens magnifications; one with a baseline lens and one with the addition of a teleconverter lens to view the same flow-field with double magnification (i.e. a finer spatial resolution). A comparison of the turbulence statistics between the rough and smooth wall, components of velocity, and pressure gradient magnitudes are analyzed. The smooth wall turbulence data consistently show a much higher sensitivity to the spatial resolution, particularly for the wall-normal component, due to the smaller eddy length-scales. A fixed camera resolution limits the measured range of scales which affects comparative magnitudes of turbulence for flows with different local Reynolds numbers. The rough wall data measurements show a variable sensitivity to the camera resolution depending on local Reynolds number and streamwise flow history. A statistical convergence study based on the anistropy of turbulence scales is necessary in experimental design for the study of turbulent boundary layers.

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Section: Experimental Facilities and Methods 21 Facilitymentioning

confidence: 99%

Spatial Resolution Limitations of Particle Image Velocimetry in High Reynolds Number Turbulent Boundary Layers

Vishwanathan

Fritsch

Devenport

et al. 2022

Preprint

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show abstract

“…The SWT is capable of reaching a maximum flow speed of approximately 80 m/s, corresponding to a Reynolds number per meter of 5 × 10 6 . The facility features two interchangeable test sections, one of which has highly modular side walls to facilitate model and instrumentation installation (Duetsch-Patel et al, 2020), as well as an instrumented contraction liner to track the surface static pressure through the contraction (Vishwanathan et al, 2020). Measurements over the BeVERLI Hill were performed in a configuration as depicted in Fig.…”

Section: Stability Wind Tunnelmentioning

confidence: 99%

Structural aspects of the attached turbulent boundary layer flow over a hill

et al. 2023

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Three-dimensional turbulent boundary layers under strong pressure gradients and curvature are the rule in real-world flow applications but are typically not well predicted by turbulence models due to isotropic eddy viscosity or equilibrium assumptions. Validation-quality data in complex 3D flows is necessary for continued efforts to improve simulation accuracy. The BeVERLI (Benchmark Validation Experiments for RANS/LES Investigations) Hill bump model, designed specifically for validation experiments, was tested in the Virginia Tech Stability Wind Tunnel to collect validation experiment data on the three-dimensional (3D) boundary layer flow over a 3D hill. Laser Doppler velocimetry measurements on the bump model were used to study the mean flow and turbulence structure and evaluate the impact of pressure gradient and curvature upon the total shear stress in the boundary layer and evaluate the impact of pressure gradient and curvature upon the total shear stress behavior in the near-wall region. From analysis of the BeVERLI Hill flow, including the boundary layer just upstream of the hill, and comparison with the 3D flow around a wing-body junction of Ölçmen et al (2001), it is shown that none of the stations studied exhibit a constant shear stress region over any significant region of the boundary layer. One station on the hill, located in a region Structural Aspects of the Attached Turbulent Boundary Layer Flow Over a Hill with strong spanwise and streamwise pressure gradients, experiences an apparent return to an equilibrium shear stress for x + 2 < 30 due to significantly increased production of u ′ 1 u ′ 2 and u ′2 2 at this station.

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Turbulence and pressure fluctuations in rough wall boundary layers in pressure gradients

et al. 2022

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Aerodynamic Design and Assessment of Modular Test Section Walls for CFD Validation in Hybrid Anechoic Wind Tunnels

Cited by 15 publications

References 7 publications

Spatial Resolution Limitations of Particle Image Velocimetry in High Reynolds Number Turbulent Boundary Layers

Spatial Resolution Limitations of Particle Image Velocimetry in High Reynolds Number Turbulent Boundary Layers

Structural aspects of the attached turbulent boundary layer flow over a hill

Turbulence and pressure fluctuations in rough wall boundary layers in pressure gradients

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