Optical flow estimation in aerated flows

Bung, Daniel B.; Valero, Daniel

doi:10.1080/00221686.2016.1173600

Cited by 72 publications

(40 citation statements)

References 16 publications

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“…Optical methods have also been used in aerated flows, the Bubble Image Velocimetry being the Particle Image Velocimetry version for aerated flows; however, the accuracy reached is not comparable. Computer Vision methods (such as Optical Flow) are arising as a robust alternative for air-water flows [102][103][104][105]108].…”

Section: Discussion On Experimental Uncertaintiesmentioning

confidence: 99%

Numerical Simulation of Hydraulic Jumps. Part 1: Experimental Data for Modelling Performance Assessment

Valero

Viti

Gualtieri

2018

Water

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Hydraulic jumps have been the object of extensive experimental investigation, providing the numerical community with a complete case study for models’ performance assessment. This study constitutes an exhaustive literature review on hydraulic jumps’ experimental datasets. Both mean and turbulent parameters characterising hydraulic jumps are comprehensively discussed, presenting at least a reference to one dataset. Three studies stand out over other datasets due to their completeness. Using them as reference for model validation may ensure homogeneous and comparable performance assessment for the upcoming numerical models. Experimental inaccuracies are also addressed, allowing the numerical modeller to understand the uncertainties of reduced physical models and its limitations. Part 2 presents the three-dimensional numerical investigations to date and their main achievements.

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Section: Discussion On Experimental Uncertaintiesmentioning

confidence: 99%

Numerical Simulation of Hydraulic Jumps. Part 1: Experimental Data for Modelling Performance Assessment

Valero

Viti

Gualtieri

2018

Water

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“…Rashwan et al [13] proposed a modified optical flow algorithm to improve the stability of the system based on tensor voting filtering. Bung et al [14] used a pyramid multi-resolution model to filter the aerated-water flow image, and then to calculate the optical flow based on the HS algorithm, thereby estimating the dynamics of the aerated-water flow. Bengtsson et al [15] proved that the optical flow estimation can track the target motion by using a camera to alternately capture the multi-frame sequence image of the moving targets.…”

Section: Related Workmentioning

confidence: 99%

Research on Moving Target Tracking Based on FDRIG Optical Flow

Gong

Wang²

2019

Symmetry

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Aiming at the problem of moving target recognition, a moving target tracking model based on FDRIG optical flow is proposed. First, the optical flow equation was analyzed from the theory of optical flow. Then, with the energy functional minimization, the FDRIG optical flow technique was proposed. Taking a road section of a university campus as an experimental section, 30 vehicle motion sequence images were considered as objects to form a vehicle motion sequence image with a complex background. The proposed FDRIG optical flow was used to calculate the vehicle motion optical flow field by the Halcon software. Comparable with the classic Horn and Schunck (HS) and Lucas and Kande (LK) optical flow algorithm, the monitoring results proved that the FDRIG optical flow was highly precise and fast when tracking a moving target. The Ettlinger Tor traffic scene was then taken as the second experimental object; FDRIG optical flow was used to analyze vehicle motion. The superior performance of the FDRIG optical flow was further verified. The whole research work shows that FDRIG optical flow has good performance and speed in tracking moving targets and can be used to monitor complex target motion information in real-time.

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“…For the setup analyzed in this paper, Bung [13] suggested h 75 , that is, the flow depth with 75% mean air concentration, as the lower extension of the surface waves. Figure 1a shows an exemplary frame taken from a high-speed video in the quasi-uniform flow region of a model test with 1:2 slope (ϕ = 26.6 • ), s = 6 cm step height and a specific discharge of q = 0.07 m 2 /s (compare [36]). The level of h 75 , detected with an air concentration probe, is also indicated.…”

Section: Specific Air-water Interfacementioning

confidence: 99%

Re-Aeration on Stepped Spillways with Special Consideration of Entrained and Entrapped Air

Bung

Valero

2018

Geosciences

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As with most high-velocity free-surface flows, stepped spillway flows become self-aerated when the drop height exceeds a critical value. Due to the step-induced macro-roughness, the flow field becomes more turbulent than on a similar smooth-invert chute. For this reason, cascades are oftentimes used as re-aeration structures in wastewater treatment. However, for stepped spillways as flood release structures downstream of deoxygenated reservoirs, gas transfer is also of crucial significance to meet ecological requirements. Prediction of mass transfer velocities becomes challenging, as the flow regime differs from typical previously studied flow conditions. In this paper, detailed air-water flow measurements are conducted on stepped spillway models with different geometry, with the aim to estimate the specific air-water interface. Re-aeration performances are determined by applying the absorption method. In contrast to earlier studies, the aerated water body is considered a continuous mixture up to a level where 75% air concentration is reached. Above this level, a homogenous surface wave field is considered, which is found to significantly affect the total air-water interface available for mass transfer. Geometrical characteristics of these surface waves are obtained from high-speed camera investigations. The results show that both the mean air concentration and the mean flow velocity have influence on the mass transfer. Finally, an empirical relationship for the mass transfer on stepped spillway models is proposed.

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Optical flow estimation in aerated flows

Cited by 72 publications

References 16 publications

Numerical Simulation of Hydraulic Jumps. Part 1: Experimental Data for Modelling Performance Assessment

Numerical Simulation of Hydraulic Jumps. Part 1: Experimental Data for Modelling Performance Assessment

Research on Moving Target Tracking Based on FDRIG Optical Flow

Re-Aeration on Stepped Spillways with Special Consideration of Entrained and Entrapped Air

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