Volumetric particle tracking velocimetry with improved algorithms using a two-view shadowgraph system

Wu, Yu; Zhao, C.Y.; Wang, Qian

doi:10.1088/1361-6501/ac6934

Cited by 5 publications

(3 citation statements)

References 35 publications

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“…Since the early 1980s, experimental fluid mechanics has undergone a revolutionary development with research in particle image velocimetry (PIV) [14]. Three-dimensional particle-tracking velocimetry is a technique based on the reconstruction of single-particle trajectories over long sequences, and it allows an accurate evaluation of the Lagrangian properties [15] unlike the 3D PIV technique, which estimates the average velocity of particles in an Euler frame with the spatial correlation method [16]. In this research, flow measurement is done using the 'Shake-The-Box' (STB) particle tracking algorithm technique.…”

Section: Introductionmentioning

confidence: 99%

Experiments of Lift-Bending Response on a Slender UAV Wing Structure with Control Surface under Extreme Flow Turbulence

Ayele,

Maldonado,

Parameswaran

2024

Aerospace

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The aeroelastic response of lightweight low-speed aircrafts with slender wings under extreme flow turbulence intensity is not well understood. Experiments on a commercial unmanned aerial vehicle (UAV) with a 3 m wingspan and aspect ratio of 13.6 were performed in a large open-return wind tunnel with extreme flow turbulence intensity of ≈10%. The wing bending displacement and the flow beneath the wing were measured by using laser-displacement sensors and tomographic particle image velocimetry (PIV) techniques, respectively. The unsteady lift produced by the wing was also measured by using a high-capacity load cell at an angle of attack of two degrees for three freestream velocities of 13.4 m/s, 17.9 m/s, and 26.8 m/s, representing the UAV’s stall speed, a speed approximately equal to the cruise speed, and a speed considerably higher than the cruise speed, respectively. It was found that a high flow turbulence intensity with large integral length scales relative to the wing chord plays a dominant role in the large unsteady lift and wing displacements measured. The power spectral density (PSD) of the wing structural vibration shows that flow shedding from the wing and the integral length scales have a significant impact on the overall power inherent in the bending vibration of the wing. Computations of the vorticity isosurfaces in the flow measurement volume surrounding the aileron reveal a striking observation: an aileron deflection of 10° becomes less effective in producing additional spanwise vorticity, which is proportional to circulation and lift at 26.8 m/s since the freestream already has elevated levels of vorticity. A paradigm shift in design is suggested for light aircraft structures with slender wings operating in highly turbulent flow, which is to employ multiple control surfaces in order to respond to this flow and mitigate large bending or torsion displacements and the probability of structural failure.

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Section: Introductionmentioning

confidence: 99%

Experiments of Lift-Bending Response on a Slender UAV Wing Structure with Control Surface under Extreme Flow Turbulence

Ayele,

Maldonado,

Parameswaran

2024

Aerospace

View full text Add to dashboard Cite

show abstract

“…Since the early 1980s, experimental fluid mechanics has undergone a revolutionary development with research in particle image velocimetry (PIV) [14]. Three dimensional particle tracking velocimetry is a technique based on reconstruction of single particle trajectories over long sequences, and it allows an accurate evaluation of the Lagrangian properties [15] unlike the 3D PIV technique which estimates the average velocity of particles in an Euler frame with the spatial-correlation method [16]. In this study, flow measurement is done using the 'Shake-The-Box' (STB) particle tracking algorithm technique.…”

Section: Introductionmentioning

confidence: 99%

Experiments of Lift-Bending Response on a Slender UAV Wing Structure with Control Surface under Extreme Flow Turbulence

Ayele,

Maldonado,

Parameswaran

2023

Preprint

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The aeroelastic response of lightweight low-speed aircraft with slender wings under extreme flow turbulence intensity is not well-understood. Experiments on a commmercial unmanned aerial vehicle (UAV) with a 3-meter wingspan and aspect ratio of 13.6 were performed in a large open-return wind tunnel with extreme flow turbulence intensity of T∞≈10%. The structural dynamics of the wing in the bending mode and the flow beneath the wing to capture the effect of aileron deflection was measured using laser displacement sensors and tomographic particle image velocimetry (PIV) techniques. The unsteady lift produced by the wing was also measured using a high-capacity load cell at an angle of attack, α of 2 degrees for three freestream velocities U∞ of 13.4 m/s, 17.9 m/s, and 26.8 m/s representing the UAV’s stall through cruise speed. It was found that high flow turbulence intensity with large integral length scales relative to the wing chord plays a dominant role in the large unsteady lift and wing displacements measured. The power spectral density (PSD) of wing structural vibration shows that flow shedding from the wing and the integral length scales have a significant impact on the overall power inherent in the bending vibration of the wing. Computation of vorticity iso-surfaces in the flow measurement volume surrounding the aileron reveal a striking observation; aileron deflection, δa of 10∘becomes less effective in producing additional spanwise vorticity, which is proportional to circulation and lift, at U∞ of 26.8 m/s because the freestream already has elevated levels of vorticity. A paradigm shift in design is suggested for light aircraft structures with slender wings operating in highly turbulent flow, which is to employ multiple control surfaces in order to respond to this flow and mitigate large bending or torsion displacements and the probability of structural failure.

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“…The synthetic data tests showed a correctness over 99% around 0.03 ppp. The algorithm has been further improved and tested by practical experiments [36]. The results indicated that more reasonable particle trajectories could be identified and the trajectory interruptions under dense particle conditions were greatly reduced.…”

Section: Introductionmentioning

confidence: 99%

A parametric study of 3D PTV algorithms based on a two-view collimated imaging model

Wang

Zhu²,

Zhao³

2022

Meas. Sci. Technol.

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The volumetric Lagrangian measurements of droplet or turbulent flow using particle tracking methods have attracted intensive attentions recently. The performance of three-dimensional particle tracking velocimetry (3D PTV) is highly relying on the algorithms. Most of the existing 3D PTV algorithms are developed for multi-view systems, which cannot be applied directly to two-view systems due to the lack of enough geometry constraints. In the current study, three different 3D PTV algorithms applicable for two-view systems have been investigated parametrically using synthetic data. The imaging model is established on a two-view collimated shadowgraph imaging setup, which features with high framing rate, large test volume and long depth focus. The performance of three algorithms has been tested under different image particle densities and displacement-spacing ratios. The correctness of 3D reconstruction and tracking, as well as the number of ghost particles are obtained and compared comprehensively. The results indicate that significant improvement has been achieved through dedicated designed algorithms. The comparative study has revealed the potential of each algorithm with extremely limited geometry constraints in two-view systems, which may serve as guidance for choosing appropriate algorithms under different test conditions.

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Volumetric particle tracking velocimetry with improved algorithms using a two-view shadowgraph system

Cited by 5 publications

References 35 publications

Experiments of Lift-Bending Response on a Slender UAV Wing Structure with Control Surface under Extreme Flow Turbulence

Experiments of Lift-Bending Response on a Slender UAV Wing Structure with Control Surface under Extreme Flow Turbulence

Experiments of Lift-Bending Response on a Slender UAV Wing Structure with Control Surface under Extreme Flow Turbulence

A parametric study of 3D PTV algorithms based on a two-view collimated imaging model

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