Evaluation of Flow Field in the Layouts of Cross-Shaped Artificial Reefs

2019 ◽  
Author(s):  
Yanli Tang ◽  
Qi Hu ◽  
Xinxin Wang ◽  
Fenfang Zhao ◽  
Liuyi Huang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Marine Species ◽  
Artificial Reefs ◽  
Aquatic Environments ◽  
Sea Floor ◽  
Transverse Distance ◽  
Sphere Of Influence ◽  
Eddy Flow

Abstract Artificial reefs (ARs) are purposely submerged in natural aquatic environments to provide additional habitat for fish. The reasonable layout of ARs on the sea floor can effectively enhance and support important marine species. This research involves a three-dimensional numerical simulation to analyze the flow effect of three types of AR layouts based on computational fluid dynamics. Through numerical simulation of the flow past the reefs, we can determine the scale of the upwelling and back-eddy flow. Based on the simulation data, the rational transverse distance between two cross-shaped artificial reefs (CSARs) is 6L (L is the length of the single reef), which is used to design the layouts of CSARs. Five indicators have been used to evaluate the flow field effect of these three layouts. According to the comparison of five indications for different layouts of CSAR, it is more reasonable to divide the AR layouts into two categories: upwelling layout and back eddy layout. Finally, the sphere of influence of the AR layouts on the fisheries resource is also discussed.

Analysis and Study of Back Eddy Flow Field Effecting Compact by Angle of Meeting Flow of Reef

2014 ◽  
Vol 501-504 ◽  
pp. 1902-1906
Author(s):  
Kai Min Wang ◽  
Yi Hong Yang ◽  
Yong Chen ◽  
Shu Guang Luan
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Artificial Reefs ◽  
Constant Flow ◽  
Three Dimensional Flow ◽  
Flow Angle ◽  
Dimensional Flow ◽  
Eddy Flow ◽  
Analysis And Study

By changing artificial-reefs meeting flow angle, Use the CFD imitate three-dimensional flow field under the compaction of constant flow, and analyze the effect of back eddy flow field quantitatively. The results show that, with the reduction of the angle of the meeting flow, the length; height; width of back eddy has the tendency of becoming small; when the angle become Ninety the effecting of the back eddys flow field is the best.

Two-Phase Flow Field Numerical Simulation in Scrubber for Exhaust Gas Desulfurization

2014 ◽  
Vol 541-542 ◽  
pp. 1288-1291
Author(s):  
Zhi Feng Dong ◽  
Quan Jin Kuang ◽  
Yong Zheng Gu ◽  
Rong Yao ◽  
Hong Wei Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flue Gas ◽  
Two Phase Flow ◽  
Three Dimensional ◽  
Flue Gas Desulfurization ◽  
Parameter Design ◽  
Phase Flow ◽  
Two Phase ◽  
Entrance Angle

Calculation fluid dynamics software Fluent was used to conduct three-dimensional numerical simulation on gas-liquid two-phase flow field in a wet flue gas desulfurization scrubber. The k-ε model and SIMPLE computing were adopted in the analysis. The numerical simulation results show that the different gas entrance angles lead to internal changes of gas-liquid two-phase flow field, which provides references for reasonable parameter design of entrance angle in the scrubber.

Numerical Simulation and Experimental Verification of the Deposition Concentration of an Unmanned Aerial Vehicle

2019 ◽  
Vol 35 (3) ◽  
pp. 367-376 ◽  
Author(s):  
Qiang Shi ◽  
Hanping Mao ◽  
Xianping Guan
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Unmanned Aerial Vehicle ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Utilization Rate ◽  
Droplet Deposition ◽  
Aerial Vehicle ◽  
Motion Characteristics

Abstract. To analyze the droplet deposition under the influence of the flow field of an unmanned aerial vehicle (UAV), a hand-held three-dimensional (3D) laser scanner was used to scan 3D images of the UAV. Fluent software was used to simulate the motion characteristics of droplets and flow fields under the conditions of a flight speed of 3 m/s and an altitude of 1.5 m. The results indicated that the ground deposition concentration in the nonrotor flow field was high, the spray field width was 2.6 m, and the droplet deposition concentration was 50 to 200 ug/cm2. Under the influence of the rotor flow field, the widest deposition range of droplets reached 12.8 m. Notably, the droplet deposition uniformity worsened, and the concentration range of the droplet deposition was 0 to 500 ug/cm2. With the downward development of the downwash flow field, the overall velocity of the flow field gradually decreased, and the influence interval of the flow field gradually expanded. In this article, the droplet concentration was verified under simulated working conditions by a field experiment, thereby demonstrating the reliability of the numerical simulation results. This research could provide a basis for determining optimal UAV operating parameters, reducing the drift of droplets and increasing the utilization rate of pesticides. Keywords: Unmanned aerial vehicle (UAV), Aerial application, Downwash flow field, Droplet deposition, Simulation analysis.

Study on the Principle of Yarn Splicing of Pneumatic Splicer Using Numerical Simulation

2012 ◽  
Vol 588-589 ◽  
pp. 1355-1358
Author(s):  
Xiao Xing ◽  
Guo Ming Ye
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Numerical Results ◽  
Simulation Results

During the splicing process of pneumatic splicer, the principle of yarn splicing is closely related to the flow field inside the splicing chamber. This paper presents a numerical simulation of the flow char-acteristics inside the splicing chamber of the pneumatic splicer. A three-dimensional grid and the realizable tur¬bulence model are used in this simulation. The numerical results of veloc¬ity vectors distribution inside the chamber are shown. Streamlines starting from the two air injectors are also acquired. Based on the simulation, the principle of yarn splicing of the pneumatic splicer is discussed. The airflow in the splicing chamber can be divided into three regions. In addition, the simulation results have well sup¬ported the principle of yarn splicing of pneumatic splicer claimed by the splicing chamber makers.

Numerical Simulation on Cylinder Flow Field of Diesel

2013 ◽  
Vol 712-715 ◽  
pp. 1330-1334
Author(s):  
Yin Dong Song ◽  
Yin Nan Yuan ◽  
Chun Ping Wu ◽  
Yong Wang Li ◽  
Peng Zhe Qi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Swirl Flow ◽  
Mixing Rate ◽  
Air Mixing ◽  
Reduce Emissions ◽  
Diesel Cylinder ◽  
Cylinder Flow ◽  
Transient Numerical Simulation

Three dimensional transient numerical simulation on cylinder flow field of 4B26 diesel was done by AVL FIRE. Detailed flow field structure of diesel cylinder was calculated. The typical swirl flow and squish flow were established in 4B26 diesel engine chamber. swirl flow and squish flow can increase the fuel and air mixing rate, and can improve diesel combustion and can reduce emissions of pollutants. Oil beam could accelerate the air around it.

Numerical simulation of three-dimensional airflow in a novel dual-feed rotor spinning box

2016 ◽  
Vol 88 (3) ◽  
pp. 237-253 ◽  
Author(s):  
Nicholus Tayari Akankwasa ◽  
Huiting Lin ◽  
Yuze Zhang ◽  
Jun Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Three Dimensional ◽  
Internal Flow ◽  
Velocity Variation ◽  
Positive Pressure ◽  
Three Dimensional Model ◽  
Air Velocity ◽  
Rotor Spinning ◽  
Pressure Profiles

In order to regulate turbulence strength and determine airflow characteristics in a new dual-feed rotor spinning unit, the internal flow field is investigated. A computational fluid dynamics technique is employed to numerically study the three-dimensional model of the internal airflow in the new design. The effects of air velocity variation on turbulence strength, negative pressure, Re, and wall pressure distribution are investigated based on simulation data and previous studies. The results show that the turbulence strength and Re increased with increase in inlet air velocity. Pressure profiles inside the rotor varied significantly with positive pressure observed at the channel exits. Minimal inlet velocity maintains the flow field in the rotor interior below 100 m/s, which gives the ideal turbulence required to minimize yarn quality deterioration. The dual-feed rotor spinning unit showed more orderly streamline patterns with fewer vortices compared to the conventional one. The numerical simulation can provide insights on airflow studies and some guidelines for future prototyping and experiments to further improve the new design.

Simulation and Experimental Analysis of the Effect of Channel Width on Flow Field in Laser Cutting

2009 ◽  
Vol 626-627 ◽  
pp. 171-176 ◽  
Author(s):  
X.J. Sheng ◽  
Jun Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Laser Cutting ◽  
Cone Angle ◽  
Three Dimensional ◽  
Channel Width ◽  
Gas Jet ◽  
Channel Surface ◽  
Symmetrical Model ◽  
Cutting Experiment

A three-dimensional axial symmetrical model of laser cutting is established by adopting N-S equation in the paper, and numerical simulation is put up to analyze the flow field of assist gas in cutting channel. The investigation reveals the law about how channel width affects the dynamic characteristic of gas jet in the cutting process, and the distributions of pressure and velocity of gas jet with different channel widths are shown in the study. The study shows that the intensity of compressed wave and expanded wave in cutting channel declines remarkably with channel width increasing, and the kinetic energy at channel surface drops while the cutting quality is deteriorated. A taper nozzle with cone angle of 30°and a convergence nozzle comprised a parabola equation of are designed for the laser cutting experiment. The experimental results are given at the end of the paper.

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