scholarly journals Study on the Separate Characteristics of Oil Spill Driven by Combined Water and Wind in Braided Rivers

2018 ◽  
Vol 246 ◽  
pp. 01118
Author(s):  
Jie Mu ◽  
Xiaoqing Liu ◽  
Chao Ma ◽  
Binbin Wu ◽  
Ruozhu Shen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Oil Pollution ◽  
Velocity Ratio ◽  
Flux Ratio ◽  
Quantitative Relationship ◽  
Particle Model ◽  
Wind Effect ◽  
Width Ratio ◽  
Two Dimensional ◽  
Braided Rivers

In general, there are many bifurcations in natural rivers. When the oil spilled accident occurred at the upstream of bifurcation and was not controlled in time, the pollution scale would be expanded and the treatment would become harder as the oil slick entered into braided river driven by combined water and wind. To Study the separate law at the bifurcation in rivers, a two-dimensional numerical simulation model of oil spilled was established by oil particle model theory on the basis of two-dimensional hydrodynamic model. The quantitative relationship between the oil separate ratio and the flux ratio, velocity ratio, width ratio was obtained driven by water. The wind effect on the proportion of oil separate was also discussed based on the oil spilled numerical simulation. This study will provide technical support for forecast and response of oil pollution in braided rivers.

scholarly journals A Random Angular Bend Algorithm for Two- Dimensional Discrete Modeling of Granular Materials

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2169 ◽  
Author(s):  
Zhenyu Wang ◽  
Lin Wang ◽  
Wengang Zhang
Keyword(s):  
Numerical Simulation ◽  
Granular Materials ◽  
Geometric Model ◽  
Detection Algorithm ◽  
Irregular Shape ◽  
Particle Flow Code ◽  
Particle Model ◽  
Two Dimensional ◽  
Solid Foundation ◽  
Random Particle

Generation of particles with irregular shape and the overlap detection are crucial for numerical simulation of granular materials. This paper presents a systematic approach to develop a two-dimensional random particle model for numerical simulation of granular materials. Firstly, a random angular bend (RAB) algorithm is proposed and coded in Python to simulate the geometric model of individual particle with irregular shape. Three representative parameters are used to quantitatively control the shape feature of generated polygons in terms of three major aspects, respectively. Then, the generated geometrical models are implemented into particle flow code PFC2D to construct the clump library. The clumps are created via the mid-surface method. Besides, an overlap detection algorithm is developed to address the difficulties associated with spatial allocation of irregularly shaped particles. Finally, two application examples are adopted to validate the feasibility of the proposed algorithm in the numerical modeling of realistic granular materials. The study provides a solid foundation for the generation and simulation of the granular materials based on angular bend theory.

Design of Blasting Scheme Based on Numerical Simulation

2013 ◽  
Vol 353-356 ◽  
pp. 1364-1369
Author(s):  
Zhen Hui Li ◽  
Yue Tang Zhao ◽  
Cheng Chu
Keyword(s):  
Numerical Simulation ◽  
Peak Velocity ◽  
Velocity Ratio ◽  
Quantitative Relationship ◽  
Vibration Velocity ◽  
Refined Oil ◽  
Oil Pipeline ◽  
Transmission Pipeline ◽  
Under Construction ◽  
Different Thickness

Operating safety of adjacent pre-constructed pipeline must be insured when the crude oil and refined oil pipeline is under construction. Applying finite element method, the peak velocities of observed points located at test segment and operating segment of West to East Gas Transmission Pipeline were calculated, and the ratio of the two peak velocities in different relative positions was also obtained. Taking advantage of quantitative relationship between the detonation charge and vibration velocity of particle on the pipeline, the ratio of detonation charge is derived from the peak velocity ratio, thereby the blasting scheme of West to East Gas Transmission Pipeline with different thickness is ascertained. This method is not only economical and convenient, but also has no damage to the pipeline, which also works for other blast schemes of different conditions.

Numerical analysis and explore of asymmetrical fluid flow in a two-sided lid-driven cavity

2020 ◽  
Vol 14 (3) ◽  
pp. 7269-7281
Author(s):  
El Amin Azzouz ◽  
Samir Houat
Keyword(s):  
Velocity Ratio ◽  
Two Dimensional ◽  
Lower Side ◽  
Square Cavity ◽  
Driven Cavity ◽  
Parallel Motion ◽  
Bottom Cavity ◽  
Secondary Vortices ◽  
Volume Method ◽  
Fluid Characteristics

The two-dimensional asymmetrical flow in a two-sided lid-driven square cavity is numerically analyzed by the finite volume method (FVM). The top and bottom walls slide in parallel and antiparallel motions with various velocity ratio (UT/Ub=λ) where |λ|=2, 4, 8, and 10. In this study, the Reynolds number Re1 = 200, 400, 800 and 1000 is applied for the upper side and Re2 = 100 constant on the lower side. The numerical results are presented in terms of streamlines, vorticity contours and velocity profiles. These results reveal the effect of varying the velocity ratio and consequently the Reynolds ratio on the flow behaviour and fluid characteristics inside the cavity. Unlike conventional symmetrical driven flows, asymmetrical flow patterns and velocity distributions distinct the bulk of the cavity with the rising Reynolds ratio. For λ>2, in addition to the main vortex, the parallel motion of the walls induces two secondary vortices near the bottom cavity corners. however, the antiparallel motion generates two secondary vortices on the bottom right corner. The parallel flow proves affected considerably compared to the antiparallel flow.

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