Structural analysis of aquaculture net cages in current

Moe, Heidi; Fredheim, Arne; Hopperstad, O.S.

doi:10.1016/j.jfluidstructs.2010.01.007

Cited by 113 publications

(73 citation statements)

References 14 publications

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“…Nevertheless, few authors (e.g., Lader et al 2008, Lee et al 2008Moe et al, 2010) have found that the internal volume loss of an aquaculture net pen may fluctuate between 20% and 70% when considering current speeds ranging between 0.13 and 1.0 m s -1 (Table 3). …”

Section: Discussionmentioning

confidence: 99%

“…These culture systems correspond to highly flexible hydro elastic structures, composed by a great number of structural elements (Kristiansen & Faltinsen, 2012) and are affected by hydrodynamic forces that modify their shape (Lader & Enerhaug, 2005). The effects of the forces generated by currents and ocean waves on the deformation of the net pens have been studied through numerical models by different authors (Aarsnes et al, 1990;Berstad et al, 2004;Lee et al, 2005;Huang et al, 2006;Lee et al, 2008;Moe et al, 2010). Few authors have conducted tests in tanks and constructed commercial size prototypes, in a more practical approach, in order to study the ocean dynamic loading (Lader & Enerhaug, 2005;Lader et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Volume loss of an aquaculture net pen due to current speed and linear weight of sinker ring

López

Hurtado

Queirolo

et al. 2015

lajar

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ABSTRACT. The internal volume of aquaculture net pens is an important variable to fish comfort during the culture process. In this research, a module of net pens was modelled using the finite element (FE) software AquaSim®. The net pens deformation was analyzed under different current speeds (0.25, 0.50 and 0.75 m s ). It was found that under the most severe condition, that is, the highest current speed and the lowest linear weight of the sinker ring (0.75 m s -1 and 25 kg m -1 , respectively), the volume loss with respect to initial undeformed net pen volume reached a maximum value of 53%. This occurred in the net pen firstly exposed to currents. Based on modeling results, a relationship between net pen volume loss due to the combined effects of both water current speed and linear weights of the sinker rings is proposed. Key words: net pen deformation, current speed, sinker ring, Chile. , respectivamente), la pérdida de volumen de la primera jaula del módulo alcanzó 53%. A partir de los resultados obtenidos en los modelos, se determinó una función que relaciona la pérdida de volumen de la jaula con la velocidad de corriente y el peso lineal del anillo cortacorrientes. Palabras clave: deformación de la jaula, velocidad de corriente, anillo cortacorriente, Chile.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Volume loss of an aquaculture net pen due to current speed and linear weight of sinker ring

López

Hurtado

Queirolo

et al. 2015

lajar

View full text Add to dashboard Cite

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“…This type of force model has been extensively applied in e.g. Moe et al (2010), Xu et al (2013a), Xu et al (2013b) and Huang et al (2006).…”

Section: Calculation Of the Quadratic Drag Resistance Coefficientsmentioning

confidence: 99%

Investigations on the porous resistance coefficients for fishing net structures

Chen

Christensen

2016

Journal of Fluids and Structures

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The porous media model has been successfully applied to numerical simulation of current and wave interaction with traditional permeable coastal structures such as breakwaters. Recently this model was employed to simulate flow through and around fishing net structures, where the unknown porous resistance coefficients were adjusted by fitting the available experimental data. In the present paper, a new approach was proposed to calculate the porous resistance coefficients based on the transformation of Morison type load model. The transformation follows the principle that the total forces acting on a net panel from Morison type load model should be equal to the forces obtained from the porous media model. In order to account for the interaction effects in-between the twines, two coefficients were introduced, and they were calibrated by minimizing the least square error function. Extensive validation cases were carried out to examine the performance of the numerical model. This includes steady current flow through plane net panels and circular fish cages, and wave interaction with plane net panels. A variety of fishing nets with different solidity ratios were used in the validation cases, from which it was seen that the overall agreement between the numerical and experimental results is fair.

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“…If the volume enclosed by the net is not sufficiently large, the space and the oxygen supply for the fish inside may be severely limited, so flexible net structures are considered an essential component of an aquaculture cage. Fluid flows interact with flexible nets in a nonlinear manner (Moe et al 2010;Lader et al 2007). The flow patterns are closely related to factors including the porosity and the geometry (Fredheim 2005;Gansel et al 2012) of the net.…”

Section: Introductionmentioning

confidence: 99%

“…When a fluid flows through a net cage, the velocity of the flow is reduced, and downstream nets then encounter a flow of lower velocity (Fredheim 2005;Berstad et al 2012;Lee et al 2008). Moreover, the resulting fluid loads on the net are dependent on various factors such as the net solidity, the Reynolds number (Re), the flow angle relative to the mesh and local accelerations of the flow between the twines (Moe et al 2010). Under the hydrodynamic forces, the net may undergo large deformations (Balash et al 2009;Sala et al 2004).…”

Section: Introductionmentioning

confidence: 99%

A Hybrid Empirical-Numerical Method for Hydroelastic Analysis of a Floater-and-Net System

et al. 2016

Journal of Ship Research

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Because of scale effects and inappropriate hydrodynamic models, the nonlinear hydroelastic response of net cages used for fish farming cannot be analyzed precisely with traditional model testing or combinations of FEMs (finite element methods) and load models. In this study, an innovative hybrid method is proposed to determine the hydroelastic response of full-scale floater-and-net systems more accurately. In this method, the net for the fish cage was vertically and peripherally divided into similar interconnected sections with different hydrodynamic parameters, which were assumed to be uniformly distributed over each section. A model of a typical section was subjected to various towing velocities, oscillation periods and amplitudes in a towing tank to simulate the potential motions of all sections in the net under various currents, waves and floater movements. By analyzing the measured hydrodynamic force from this test section, a hydrodynamic force database for a typical net section under various currents, waves and floater motions was built. Finally, based on an FEM, the modified Morison equation and the hydrodynamic force database, the hydroelastic behavior of the full-scale fish cage was calculated with an iterative scheme. It is demonstrated that this hybrid method is able to produce correct hydroelastic response for both steady and oscillatory flows. The hydroelastic response of a 2D example of a full-length net panel with steady currents and floater oscillations was studied in detail.

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Structural analysis of aquaculture net cages in current

Cited by 113 publications

References 14 publications

Volume loss of an aquaculture net pen due to current speed and linear weight of sinker ring

Volume loss of an aquaculture net pen due to current speed and linear weight of sinker ring

Investigations on the porous resistance coefficients for fishing net structures

A Hybrid Empirical-Numerical Method for Hydroelastic Analysis of a Floater-and-Net System

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