A Numerical Parameter Study on Current Forces on Circular Aquaculture Net Cages

2013 ◽  
Author(s):  
Trygve Kristiansen
Keyword(s):  
Experimental Data ◽  
Current Velocity ◽  
Recent Experimental Data ◽  
Parameter Study ◽  
Force Model ◽  
Scaling Effects ◽  
Numerical Parameter ◽  
Solidity Ratio ◽  
Net Cage ◽  
Net Cages

The focus in this paper is on current forces on circular aquaculture nets, and how they vary with different parameters. The main parameters are current velocity and profile, solidity ratio of the net, sinker weights and net depth. The drag force on the net is calculated by a newly developed screen type force model. A subset of the calculations are validated by recent experimental data. The presented results are meant to represent a basis for discussing how current loads on a net cage vary with different environmental and strucural parameters. Scaling effects are discussed.

Numerical Analysis of Net Cage Dynamic Behavior Due to Concurrent Waves and Current

2009 ◽  
Author(s):  
Katsuya Suzuki ◽  
Shinsuke Torisawa ◽  
Tsutomu Takagi
Keyword(s):  
Dynamic Behavior ◽  
Wave Height ◽  
Current Velocity ◽  
Large Body ◽  
Pressure Sensors ◽  
Computational Method ◽  
Volume Deformation ◽  
Net Cage ◽  
Net Cages ◽  
A Current

Large offshore net cages have been rather successful in reducing coastal contamination and developing aquacultural technology for raising large body-size species such as bluefin tuna. Deformation and shrinkage of net cages due to severe current and waves is one of the main causes of mortality of cultivated fish, and is thus of great concern for marine cage aquaculture. Even though the cage depth can be determined by pressure sensors at several locations on the cage, this is generally insufficient to measure the deformation and shrinkage. In this study, the dynamic shape and volume of a net cage under the influence of current and waves was analyzed using a numerical net geometry simulator previously validated by tank tests. The dynamic behavior of finite mass points distributed on the net cage under various wave and current conditions was simulated in detail, and reduction coefficients of the volume were calculated by the positions of these mass points on the cage. A drastic reduction of the cage volume occurred for a current velocity of 0.28–0.39 m/s. As the current velocity increased, the deepest point of the cage changed position, moving toward the downstream direction. The effective reduction of cage volume for a wave height of 3 m and a current velocity of 0.26 m/s was the same as that for a wave height of 5 m without any current. These results suggest that the volume deformation must be based on the actual measured depth of each part of the net cage, that the combination of wave levels and current velocities may have synergistic effects on the reduction of cage volume, and that our computational method is valid for estimating the volume reduction of a net cage under the influence of a concurrent wave and current field.

Fusion and Breakup Reactions of 17S + 208Pb and 15C + 232ThHalo Nuclei Systems

2015 ◽  
Vol 11 (2) ◽  
pp. 2972-2978
Author(s):  
Fouad A. Majeed ◽  
Yousif A. Abdul-Hussien
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Fusion Reaction ◽  
Fusion Cross Section ◽  
Reaction Cross ◽  
Recent Experimental Data ◽  
Barrier Distribution ◽  
Coupled Channel ◽  
Total Fusion ◽  
Full Quantum

In this study the calculations of the total fusion reaction cross section have been performed for fusion reaction systems 17F + 208Pb and 15C + 232Th which involving halo nuclei by using a semiclassical approach.The semiclassical treatment is comprising the WKB approximation to describe the relative motion between target and projectile nuclei, and Continuum Discretized Coupled Channel (CDCC) method to describe the intrinsic motion for both target and projectile nuclei. For the same of comparsion a full quantum mechanical clacualtions have been preforemd using the (CCFULL) code. Our theorticalrestuls are compared with the full quantum mechaincialcalcuations and with the recent experimental data for the total fusion reaction  checking the stability of the distancesThe coupled channel calculations of the total fusion cross section σfus, and the fusion barrier distribution Dfus. The comparsion with experiment proves that the semiclassiacl approach adopted in the present work reproduce the experimental data better that the full quantal mechanical calcautions. 

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