scholarly journals Calculation of the maximum velocity of gravity flow in the pond-clarifier with higher aquatic plants

2020 ◽  
Vol 168 ◽  
pp. 00061
Author(s):  
Yevhen Semenenko ◽  
Tetіana Demchenko ◽  
Artyom Pavlichenko
Keyword(s):  
Free Surface ◽  
Aquatic Plants ◽  
Fluid Velocity ◽  
Maximum Velocity ◽  
Resistance Coefficient ◽  
Gravity Flow ◽  
Recycled Water ◽  
Higher Aquatic Plants ◽  
Two Parameters ◽  
The Given

The analysis of the possible maximum fluid flow rates when using higher aquatic plants for clarification of recycled water in the pondclarifier of the tailing pond has carried out. The study has been performed on the basis of a mathematical model of a plane slow stationary gravity flow of a viscous fluid in two parallel layers. The results of the study made it possible to determine the fluid velocity through a layer of higher aquatic plants floating on a free surface. The maximum possible velocity depending on the layer porosity has been determined. This value is necessary to determine the rational parameters of the process of clarifying technical recycled water from particles of the given hydraulic size, taking into account the pond-clarifier geometric dimensions. It is shown that the velocity in the layer with higher aquatic plants has been determined by the ratio of two parameters of this layer - porosity and dimensionless resistance coefficient. It has been shown that the maximum velocity value coefficient in the layer with plants floating on free surface depends only on porosity of this layer and does not depend on its resistance coefficient.

137Cs and 90Sr Accumulation by Higher Aquatic Plants and Phytoepiphyton in Water Bodies of Urban Territories

2008 ◽  
Vol 44 (1) ◽  
pp. 48-59
Author(s):  
P. D. Klochenko ◽  
G. V. Kharchenko ◽  
V. G. Klenus ◽  
A. Ye. Kaglyan ◽  
T. F. Shevchenko
Keyword(s):  
Aquatic Plants ◽  
Water Bodies ◽  
Higher Aquatic Plants ◽  
Urban Territories

scholarly journals Experiments on generation of surface waves by an underwater moving bottom

2015 ◽  
Vol 471 (2178) ◽  
pp. 20150069 ◽  
Author(s):  
Timothée Jamin ◽  
Leonardo Gordillo ◽  
Gerardo Ruiz-Chavarría ◽  
Michael Berhanu ◽  
Eric Falcon
Keyword(s):  
Free Surface ◽  
Surface Waves ◽  
Surface Deformation ◽  
Fluid Layer ◽  
Fluid Velocity ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass ◽  
Spatio Temporal ◽  
Experimental Findings

We report laboratory experiments on surface waves generated in a uniform fluid layer whose bottom undergoes an upward motion. Simultaneous measurements of the free-surface deformation and the fluid velocity field are focused on the role of the bottom kinematics (i.e. its spatio-temporal features) in wave generation. We observe that the fluid layer transfers bottom motion to the free surface as a temporal high-pass filter coupled with a spatial low-pass filter. Both filter effects are often neglected in tsunami warning systems, particularly in real-time forecast. Our results display good agreement with a prevailing linear theory without any parameter fitting. Based on our experimental findings, we provide a simple theoretical approach for modelling the rapid kinematics limit that is applicable even for initially non-flat bottoms: this may be a key step for more realistic varying bathymetry in tsunami scenarios.

scholarly journals Modeling Free Surface Flows Using Stabilized Finite Element Method

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Deepak Garg ◽  
Antonella Longo ◽  
Paolo Papale
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Free Surface ◽  
Numerical Scheme ◽  
Stokes Equations ◽  
Fluid Velocity ◽  
Computer Code ◽  
Free Surface Flows ◽  
Surface Flows ◽  
Element Method

This work aims to develop a numerical wave tank for viscous and inviscid flows. The Navier-Stokes equations are solved by time-discontinuous stabilized space-time finite element method. The numerical scheme tracks the free surface location using fluid velocity. A segregated algorithm is proposed to iteratively couple the fluid flow and mesh deformation problems. The numerical scheme and the developed computer code are validated over three free surface problems: solitary wave propagation, the collision between two counter moving waves, and wave damping in a viscous fluid. The benchmark tests demonstrate that the numerical approach is effective and an attractive tool for simulating viscous and inviscid free surface flows.

scholarly journals RESEARCH OF THE EJECTING PROPERTIES OF A POLYFRACTION BULK MATERIAL FLOW

2018 ◽  
Vol 3 (3) ◽  
pp. 46-51
Author(s):  
Евгений Попов ◽  
Evgeniy Popov
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Material Flow ◽  
Bulk Material ◽  
Aerodynamic Resistance ◽  
Average Diameter ◽  
Resistance Coefficient ◽  
Free Falling ◽  
The Given

This work is aimed at confirming the adequacy of the probabilistic and statistical approach to determining the aerodynamic resistance coefficient of particles in a flow of the free falling polyfractional material, suggested by the author. The aerodynamic resistance coefficient of particles in a flow of falling material is defined by calculating the probability of finding particles out of air shadows of the neighboring particles. The laboratory experiment was performed on the offered experimental samples of bulk materials having different particle size distribution, but the identical average diameter of particles. The design of a laboratory experimental installation which allows determining the consumption of air, ejected by a polyfractional material flow, was described. The amount of the air, ejected with experimental samples, depends on their particle size distribution that confirms the insufficiency of describing the properties of bulk material only with the average diameter value. The given comparison of results of the analytical calculations with experimental data shows the reliability and adequacy of the calculated values.

scholarly journals On generation and propagation of tsunamis in a shallow running ocean

1978 ◽  
Vol 1 (3) ◽  
pp. 373-390
Author(s):  
Lokenath Debnath ◽  
Uma Basu
Keyword(s):  
Free Surface ◽  
Three Dimensional ◽  
Relative Magnitude ◽  
Ocean Floor ◽  
Surface Elevation ◽  
Free Surface Elevation ◽  
Surface Disturbance ◽  
Fourier And Laplace Transforms ◽  
The Given ◽  
Integral Solutions

A theory is presented of the generation and propagation of the two and the three dimensional tsunamis in a shallow running ocean due to the action of an arbitrary ocean floor or ocean surface disturbance. Integral solutions for both two and three dimensional problems are obtained by using the generalized Fourier and Laplace transforms. An asymptotic analysis is carried out for the investigation of the principal features of the free surface elevation. It is found that the propagation of the tsunamis depends on the relative magnitude of the given speed of the running ocean and the wave speed of the shallow ocean. When the speed of the running ocean is less than the speed of the shallow ocean wave, both the two and the three dimensional free surface elevation represent the generation and propagation of surface waves which decay asymptotically ast−12for the two dimensional case and ast−1for the three dimensional tsunamis. Several important features of the solution are discussed in some detail. As an application of the general theory, some physically realistic ocean floor disturbances are included in this paper.

Nonlinear Local Analysis of Steady Flow About a Ship

1991 ◽  
Vol 35 (04) ◽  
pp. 288-294
Author(s):  
F. Noblesse ◽  
D. M. Hendrix ◽  
L. Kahn
Keyword(s):  
Free Surface ◽  
Fluid Velocity ◽  
Wave Profile ◽  
Local Analysis ◽  
Experimental Measurements ◽  
Surface Boundary ◽  
Nonlinear Method ◽  
Rapid Variation ◽  
Wigley Hull ◽  
Analytical Expressions

A nonlinear local analysis of the steady potential flow at a ship bow and stern, and more generally at any point along a ship waterline, is presented. The hull boundary condition and the nonlinear kinematic and dynamic free-surface boundary conditions are satisfied exactly, at the actual position of the free surface, in this analysis. The bow-flow analysis shows that the free surface at a ship bow is tangent to the stem. This theoretical result appears to agree with existing experimental measurements of steady bow waves of the Wigley hull. Simple analytical expressions defining the fluid velocity at the bow and the stern, and more generally at any point along the wave profile, in terms of the elevation of the free surface at the corresponding point are also given. These analytical expressions and the available experimental measurements of wave profiles along the Wigley hull show that the velocity of the flow disturbance due to this hull is fairly small compared to the hull speed everywhere along the wave profile except in very small regions around the bow and the stern, where the total fluid velocity is nearly equal to the hull speed in magnitude but directed vertically. Nonlinearities therefore appear to be quite important, although only in very small regions surrounding a ship bow and stern. A genuine nonlinear method of calculation must then be able to represent the very rapid variation in the direction of the fluid velocity occurring within small regions around a ship bow and stern. In particular, a sufficiently fine discretization is required in these regions.

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