Experimental and Numerical Investigations of the Hydrodynamic Characteristics, Twine Deformation, and Flow Field Around the Netting Structure Composed of Two Types of Twine Materials for Midwater Trawls

Thierry, Bruno Nyatchouba Nsangue; Tang, Hao; Achile, Njomoue Pandong; Xu, Liuxiong; Zhou, Cheng; Hu, Fuxiang

doi:10.1007/s11802-021-4740-1

Cited by 11 publications

(6 citation statements)

References 44 publications

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“…The notion that the velocity reduction increased with decreasing tilt angle and mesh opening was demonstrated in the flow study around the fishing net by Bouhoubeiny et al 25 , Druault et al 20 , and Bi et al 48 . This trend was also confirmed by the study of the turbulent flow around the bottom trawl net by Druault et al 24 , and Thierry et al 14 .…”

Section: Discussionsupporting

confidence: 64%

“…For the improvement of trawl selectivity, they predominantly examined the mesh size in relation to the fish size 10 , 11 . However, to better understand the engineering performance and the selectivity of trawl nets, the coupled dynamics of the unsteady turbulent flow developing inside and around the trawl net and fluttering motions of trawl should be considered as the main factors affecting trawl performance 12 – 14 . Indeed, the intense motion of the water can severely deform the trawl net leading to the development of unsteady turbulent flows 15 , 16 .…”

Section: Introductionmentioning

confidence: 99%

“…The analysis of the complex interaction between unsteady turbulent flow and the moving trawl structure including catch is a fundamental scientific topic that has drawn increased attention and studies in scientific research in both simulation and experimental work 20 – 22 . This analysis provides a better understanding of the flow behavior and oscillatory motions of the trawl net, thus affords relevant information for the analysis of hydrodynamic forces and selectivity via the fish response, such as the herding response or escape behavior 10 , 14 . Indeed, the fluid flow loads inside and around a trawl net structure can be clarified in static and dynamic loads, and are directly related to its elastic and dynamic instabilities 13 , 23 .…”

Section: Introductionmentioning

confidence: 99%

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Turbulent flow interacting with flexible trawl net structure including simulation catch in flume tank

Thierry

Tang

Liu

et al. 2023

Sci Rep

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The interaction between fluid and the midwater trawl with stocked catches is extremely complex, but essential to improve the understanding of the drag force acting on the trawl, the behavior of the fishing structure during a trawling process, and to predict its selectivity process. The present study assesses the turbulent characteristics inside and around the midwater trawls with catch and without catch linked to its fluttering motion. The analysis is based on three-dimensional electromagnetic current velocity meter measurements performed in the multiple points inside and outside different parts of a 1/35 scaled midwater trawl model with the aim of access the main turbulent flow structure inside and around the gear. Time-averaged normalized flow velocity fields and turbulent flow parameters were analyzed from the measured flow data. Furthermore, Fourier analysis was conducted by watching the time–frequency Power spectrum content of instantaneous flow velocities fields, the fluttering trawl motions, turbulent kinetic energy, and momentum flux. Based on successive analyzes of mean flow characteristics and turbulent flow parameters, it has been demonstrated that the presence of catch inside the trawl net impacts the evolution of unsteady turbulent flow by creating large trawl fluttering motions that strongly affect the flow passage. The results showed that the time-averaged normalized streamwise and transverse flow velocities inside and around the trawl net with catch were 12.41% lower compared with that obtained inside and around the trawl without catch. The turbulent length scale and turbulent Reynolds number obtained in the different part of the trawl net with catch were about 33.05% greater than those obtained on the trawl net without catch, confirming that the unsteady turbulent flow developing inside and around the midwater trawl is influence by the catch and liner. It is observed that the motions of both the trawl without catch and the trawl with catch are mainly of a low-frequency activity and another component related to unsteady turbulent flow street. A complex fluid–structure interaction is then demonstrated where the fluttering motions of the trawl net affect the fluid flow inside and around trawl net, the fluid force, turbulent pattern, and simultaneously, the periodic unsteady turbulent flow influence the trawl motions.

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Section: Discussionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Turbulent flow interacting with flexible trawl net structure including simulation catch in flume tank

Thierry

Tang

Liu

et al. 2023

Sci Rep

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“…Additionally, another reason, apart from what we mentioned above, was that because of the higher resistance performance of PE netting material, the PE nettings have a lower sinking performance compared to PA and PES nettings. The other reason was that, according to Thierry et al [20], the hydrodynamic forces of PA and PES netting were lower than those obtained using PE netting, which is probably why the nettings made with PES and PA nettings sink faster and have better sinking performance compared to the ones made with PE netting under the same other conditions. Thus, according to Kim et al [29] and the present study, a greater-density model net sinks faster than a lower-density model net.…”

Section: Effect Of Twine Materials and Knot Types On The Netting Sink...mentioning

confidence: 94%

“…The solidity ratio is the ratio between the projected area of a netting panel and its outline area, i.e., the total area enclosed by the netting panel. According to Thierry et al [20], the solidity ratio of a netting panel is expressed as follows:…”

Section: Experiments Samplesmentioning

confidence: 99%

Sinking Behavior of Netting Panels Made with Various Twine Materials, Solidity Ratios, Knot Types, and Leadline Weights in Flume Tank

Shan,

Tang,

Thierry

et al. 2023

JMSE

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Netting is an important component of fishing gear design, and its ability to sink determines the effectiveness of fishing gears such as purse seines, falling nets, and stick-held nets. Therefore, it is crucial to thoroughly investigate the sinking parameters (sinking depth and sinking speed) of the netting panel as a function of the leadline weights using various twine materials, knot types, and solidity ratios. In this study, a generalized additive model (GAM) was utilized to analyze the impact of each factor on the sinking performances of the netting. The results revealed that the sinking depth of the netting was positively correlated with sinking time and leadline weight. However, the netting featured a maximum sinking depth limit, indicating that the sinking depth would not increase beyond a leadline weight of 69.5 g. During the initial phase of the sinking process, the sinking velocity of each netting panel initially increased but gradually decreased over time. The incorporation of a leadline weight reduced sinking time. Thereby, polyester netting exhibited the shortest average sinking time. A comparison of netting types with similar solidity ratios showed that the maximum sinking depth of the nylon netting was 13.20% and 10.11% greater than that of polyethylene and polyester nettings, respectively. In addition, nylon nets’ time average sinking speed was 64.58% and 4.62% greater than that of polyethylene and polyester nettings, respectively. The analysis of the GAM model clearly showed that the leadline weight has a significant effect on the netting sinking speed and depth. To ensure that the netting can reach its maximum sinking speed, it is strongly recommended to use nylon and polyester nettings with a low solidity ratio, i.e., a lower twine diameter and greater mesh size with a higher leadline weight, when constructing fishing gear such as purse seines with higher net leadline weights.

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Examining engineering performance of midwater trawl with different horizontal spread ratio, floatage, and weight parameters: A case study of model net for Antarctic krill fisheries

Thierry

Tang

Achille

et al. 2022

International Journal of Naval Architecture and Ocean Engineeri

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Experimental and Numerical Investigations of the Hydrodynamic Characteristics, Twine Deformation, and Flow Field Around the Netting Structure Composed of Two Types of Twine Materials for Midwater Trawls

Cited by 11 publications

References 44 publications

Turbulent flow interacting with flexible trawl net structure including simulation catch in flume tank

Turbulent flow interacting with flexible trawl net structure including simulation catch in flume tank

Sinking Behavior of Netting Panels Made with Various Twine Materials, Solidity Ratios, Knot Types, and Leadline Weights in Flume Tank

Examining engineering performance of midwater trawl with different horizontal spread ratio, floatage, and weight parameters: A case study of model net for Antarctic krill fisheries

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