Model Testing of Fish Farms for Validation of Analysis Programs

2014 ◽  
Author(s):  
Are Johan Berstad ◽  
Line Fludal Heimstad ◽  
Jørgen Walaunet
Keyword(s):  
Numerical Analysis ◽  
Structural Integrity ◽  
State Of The Art ◽  
Scale Model ◽  
Analysis Tool ◽  
Fish Farms ◽  
Model Experiments ◽  
Cage System ◽  
Aquaculture Industry

This paper presents a case study where results from numerical analysis have been compared to model experiments, performed on a 1/16 scale model. The tested model is a circular cage system with a polyethylene cage. The system is tested both in waves and current. Numerical analysis to document the structural integrity of the fish farms are now a requirement. The state of the art analysis tool used in the aquaculture industry is AquaSim [1]. Results from model experiments are compared to numerical analysis carried out in AquaSim. Uncertainties in the model experiments are investigated and discussed. The differences between the experimental and numerical results are in the same range as the uncertainties.

scholarly journals Stability analysis of an abandoned deep metal mine using numerical analysis tool: A case study

2021 ◽  
Vol 861 (3) ◽  
pp. 032091
Author(s):  
Praveena Das Jennifer ◽  
Sripad R Naik ◽  
P Porchelvan ◽  
Harsha Tadavarthi
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Analysis Tool ◽  
Metal Mine

Numerical Investigation on the Cage-to-Cage Wake Effect: A Case Study of a 4 × 2 Cage Array

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Jaesub Sim ◽  
Hui Cheng ◽  
Karl Gunnar Aarsæther ◽  
Lin Li ◽  
Muk Chen Ong
Keyword(s):  
Drag Force ◽  
Fish Farm ◽  
Fish Farms ◽  
Wake Effect ◽  
Cage System ◽  
Flow Interactions ◽  
Wake Effects ◽  
Fish Cages ◽  
Cage Fish

Abstract Aquaculture has been the world’s fastest-growing food producing method and grown to become the second-largest export industry in Norway during the past 40 years. Usually, the high-value fish such as Atlantic Salmon (Salmo Salar) is raised in a multi-cage fish farm, where the flow interactions between fish cages exist. In this study, the interactions between fish cages are implemented into the numerical program, FhSim, to investigate its influences on the responses of a multi-cage fish farm. Tensions in anchor lines, drag force, and cultivation volume of each cage in a full-scale 4 × 2 multi-cage fish farms under different flow directions are analyzed numerically. The discrepancies of the responses based on three cases, i.e., (i) without any wake effects, (ii) with only cage-to-cage wake effect, and (iii) with all the wake effects, are compared and discussed. The results indicate that neglecting the wake effects will overestimate the total drag force of the eight cages up to 128% and underestimate the total cultivation volume of the eight cages as much as 42%. This study can provide suggestions on how to consider the wake effects during the design of the multiple-cage system.

scholarly journals Accuracy of Simplified Methods for Fatigue Damage Estimation of Exposed Fish Farms

2020 ◽  
Author(s):  
Martin Slagstad ◽  
Pål Takle Bore ◽  
Jørgen Amdahl
Keyword(s):  
Fatigue Damage ◽  
State Of The Art ◽  
Damage Estimation ◽  
Fish Farms ◽  
Safety Level ◽  
Exposed Fish ◽  
Traditional Design ◽  
Modeling Techniques ◽  
Simplified Procedures

Abstract Fish farms are being placed in more exposed locations than earlier, encouraged by the “development licenses” that the Norwegian Directorate of Fisheries have introduced. Traditional design methods for estimating fatigue damage for fish farms are based on formulations given in the code NS - 9415 Marine fish farms. These methods are initially developed for sheltered areas and may not give an adequate level of safety in more exposed locations, where the dynamic response from waves is of greater importance. Accurate calculations using state of the art methods are very time consuming both with respect to man hours, but especially with regard to CPU consumption. Hence, for practical design, simplified procedures, such as combination of the design wave method with an assumed Weibull distribution, are often used to limit the complexity of the analysis as well as the costs. To the authors knowledge, the accuracy of such simplified methods is not well documented for exposed fish farms and with limited full-scale experience it is difficult to conclude that the desired safety level is achieved. This paper addresses this problem by investigating the accuracy of simplified methods to estimate the fatigue damage. A case study of a modern fish farm concept for exposed waters is performed where the simplified methods are compared to more complex time-domain analyses using state of the art modeling techniques.

A Case Study for an Offshore Structure for Aquaculture: Comparison of Analysis With Model Testing

2018 ◽  
Author(s):  
Are Johan Berstad ◽  
Jan Vidar Aarsnes
Keyword(s):  
Numerical Simulations ◽  
Model Test ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Model Testing ◽  
Fish Farms ◽  
Offshore Structure ◽  
Gas Industry ◽  
Aquaculture Industry

This paper presents a case study of a structure of a novel fish farm cage. The “AquaTraz” cage is more similar to structures known to the the oil and gas industry. The cage has the same shape as the normal cages used in the aquaculture industry and can be introduced to existing grid-moorings. Model testing has been carried out and results from the model test are compared with results from numerical simulations using the tool AquaSim. The response deviating from classic fish farms is shown and what extra considerations that should be carried out for this type of systems compared to classic fish farms is discussed.

Centrality Measures

2018 ◽  
Author(s):  
Ginestra Bianconi
Keyword(s):  
State Of The Art ◽  
Centrality Measures ◽  
Eigenvector Centrality ◽  
Multilayer Networks ◽  
Comprehensive Description ◽  
Multilayer Network ◽  
Suitable Definition ◽  
Katz Centrality ◽  
Pagerank Centrality

Defining the centrality of nodes and layers in multilayer networks is of fundamental importance for a variety of applications from sociology to biology and finance. This chapter presents the state-of-the-art centrality measures able to characterize the centrality of nodes, the influences of layers or the centrality of replica nodes in multilayer and multiplex networks. These centrality measures include modifications of the eigenvector centrality, Katz centrality, PageRank centrality and Communicability to the multilayer network scenario. The chapter provides a comprehensive description of the research of the field and discusses the main advantages and limitations of the different definitions, allowing the readers that wish to apply these techniques to choose the most suitable definition for his or her case study.

Experimental Study for SPAR Type Floating Offshore Wind Turbine With Blade-Pitch Control

2013 ◽  
Author(s):  
Toshiki Chujo ◽  
Yoshimasa Minami ◽  
Tadashi Nimura ◽  
Shigesuke Ishida
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Offshore Wind ◽  
Scale Model ◽  
Offshore Wind Turbine ◽  
Experimental Proof ◽  
Pitch Control ◽  
Model Experiments ◽  
North Eastern ◽  
North Eastern Part

The experimental proof of the floating wind turbine has been started off Goto Islands in Japan. Furthermore, the project of floating wind farm is afoot off Fukushima Prof. in north eastern part of Japan. It is essential for realization of the floating wind farm to comprehend its safety, electric generating property and motion in waves and wind. The scale model experiments are effective to catch the characteristic of floating wind turbines. Authors have mainly carried out scale model experiments with wind turbine models on SPAR buoy type floaters. The wind turbine models have blade-pitch control mechanism and authors focused attention on the effect of blade-pitch control on both the motion of floater and fluctuation of rotor speed. In this paper, the results of scale model experiments are discussed from the aspect of motion of floater and the effect of blade-pitch control.

Sign in / Sign up

Export Citation Format

Share Document