scholarly journals Computation of 3D Water Flows by the Double Potential Method for the Simulation of Electromagnetic Water Purification

2020 ◽  
Vol 226 ◽  
pp. 02021 ◽  
Author(s):  
Nikita Tarasov ◽  
Sergey Polyakov ◽  
Tatiana Kudryashova
Keyword(s):  
Water Purification ◽  
Numerical Scheme ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Potential Method ◽  
Software Implementation ◽  
Three Dimensional Flow ◽  
Exponential Transformation ◽  
Water Flows ◽  
Volume Method

In this paper, we discuss the modeling of the electromagnetic water purification. This model requires a velocity distribution in a study domain. For that purpose, the double potential method for simulating incompressible viscous fluid flows was used. The system of equations was discretized with the help of the finite volume method using an exponential transformation for the vortex calculation. As a result, a software implementation of the developed numerical scheme was obtained. The simulation of the three-dimensional flow was carried out in a study domain. The results were compared with Ansys CFD. The comparison showed a good degree of consistency between the two distributions. Using the obtained velocity field, we simulated the process of water purification using the induction of the electromagnetic field.

Using the DLR-F6 Aircraft Model for the Evaluation of the Academic CFD Code “Galatea”

2014 ◽  
Author(s):  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Large Fraction ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Fluid Flows ◽  
Wind Tunnels ◽  
Navier Stokes ◽  
Test Case ◽  
Tetrahedral Elements ◽  
Computational Performance ◽  
Volume Method

Nowadays, the research in the aerospace scientific field relies strongly on CFD (Computational Fluid Dynamics) algorithms, avoiding (initially at least) a large fraction of the extremely time and money consuming experiments in wind tunnels. In this paper such a recently developed academic CFD code, named Galatea, is presented in brief and validated against a benchmark test case. The prediction of compressible fluid flows is succeeded by the relaxation of the Reynolds Averaged Navier-Stokes (RANS) equations, along with appropriate turbulence models (k-ε, k-ω and SST), employed on three-dimensional unstructured hybrid grids, composed of prismatic, pyramidical and tetrahedral elements. For the discretization of the computational field a node-centered finite-volume method is implemented, while for improved computational performance Galatea incorporates an agglomeration multigrid methodology and a suitable parallelization strategy. The proposed algorithm is evaluated against the Wing-Body (WB) and the Wing-Body-Nacelles-Pylons (WBNP) DLR-F6 aircraft configurations, demonstrating its capability for a good performance in terms of accuracy and geometric flexibility.

Amplification of three-dimensional perturbations during parallel vortex–cylinder interaction

2007 ◽  
Vol 573 ◽  
pp. 457-478
Author(s):  
X. LIU ◽  
J. S. MARSHALL
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Front Surface ◽  
Inviscid Flow ◽  
Reynolds Numbers ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Flow Features ◽  
Volume Method ◽  
Proper Orthogonal

A computational study has been performed to examine the amplification of three-dimensional flow features as a vortex with small-amplitude helical perturbations impinges on a circular cylinder whose axis is parallel to the nominal vortex axis. For sufficiently weak vortices with sufficiently small core radius in an inviscid flow, three-dimensional perturbations on the vortex core are indefinitely amplified as the vortex wraps around the cylinder front surface. The paper focuses on the effect of viscosity in regulating amplification of three-dimensional disturbances and on assessing the ability of two-dimensional computations to accurately model parallel vortex–cylinder interaction problems. The computations are performed using a multi-block structured finite-volume method for an incompressible flow, with periodic boundary conditions along the cylinder axis. Growth of three-dimensional flow features is examined using a proper-orthogonal decomposition of the Fourier-transformed vorticity field in the azimuthal and axial directions. The interaction is examined for different axial wavelengths and amplitudes of the initial helical vortex waves and for three different Reynolds numbers.

scholarly journals Vortex Valve – Principle, Design and Application

2018 ◽  
Vol 11 (2) ◽  
pp. 9
Author(s):  
Karel Adámek ◽  
Jan Kolář ◽  
Pavel Peukert
Keyword(s):  
Numerical Simulation ◽  
Flow Characteristic ◽  
Three Dimensional ◽  
Flow Fields ◽  
Water Levels ◽  
Three Dimensional Flow ◽  
One Dimensional ◽  
Transitional Area ◽  
Water Flows ◽  
High Flows

The paper contains the overview of so-called vortex valve, used as outlet device on retention reservoirs for retention of rainstorms and later slow outflow into drainage etc. Simple one-dimensional equations are well known, but for complex three-dimensional flow fields inside the valve the method of flow numerical simulation is used. Particular paragraphs contain the theory of flow fields inside, explanation of branched flow characteristic, separated by transitional area, basics of designing and influence of both inlet/outlet opening sizes on the form of characteristic, valve adaptation for high flows at low water levels etc. Results are used for designing of new model series of valves for various water flows and levels.

Numerical Analysis of Three-Dimensional Flows of Wormlike Micelles Solutions Through Abrupt Contraction Using a Modified Bautista-Manero Model

2011 ◽  
Author(s):  
Takehiro Yamamoto
Keyword(s):  
Structural Change ◽  
Cross Section ◽  
Numerical Scheme ◽  
Three Dimensional ◽  
Wormlike Micelles ◽  
Orientation Behavior ◽  
Shear Deformations ◽  
Limited Region ◽  
Abrupt Contraction ◽  
Volume Method

Startup flows of wormlike micelles solutions in a three-dimensional rectangular abrupt contraction channel are numerically simulated using a modified Bautista-Manero model as a constitutive equation. The numerical scheme applied is based on the finite volume method with the PISO algorithm, and the DEVSS method is employed to stabilize the numerical computation. Temporal changes in micelle network structures are investigated based on the analysis of the fluidity, which represents the structural change in micelle networks. The numerical results indicate that the orientation behavior of micelle networks around the entrance to the contraction remarkably changes with time. Around the entrance, micelle networks undergo strong elongation and shear deformations and hence the deformation of network is accelerated. Furthermore, the velocity distribution in a cross section takes a plug-like profile similarly to that of viscoplastic fluids because the fluidity rapidly changes near channel walls, where the shear rate is high. Three-dimensional patterns in the distribution of the fluidity appear more remarkably at high Weissenberg numbers, while in a conduit downstream of a contraction part they appears in a limited region near the walls where the fluidity rapidly changes.

Three-Dimensional Flow Problems in a Lid-Driven Cubical Cavity with a Circular Cylinder

2017 ◽  
Vol 18 (3-4) ◽  
pp. 187-196 ◽  
Author(s):  
Faycel Hammami ◽  
Basma Souayeh ◽  
Brahim Ben-Beya
Keyword(s):  
Reynolds Number ◽  
Circular Cylinder ◽  
Transverse Velocity ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Number Range ◽  
Driven Cavity ◽  
Flow Problems ◽  
Volume Method ◽  
Cubical Cavity

AbstractThree-dimensional numerical simulations were conducted for lid-driven cavity phenomena around an inner circular cylinder positioned in the center of a cubic enclosure in the Reynolds number range of (100≤Re≤2000) at the Prandtl number of Pr=0.71. The numerical method is based on the finite volume method (FVM) and multigrid acceleration. In this study, the transition of the flow regime from steady state to the unsteady state and consequent three-dimensionality in the system induced by the increase of Reynolds number to (Re=1798) were investigated. By increasing further Reynolds number over the critical value, the flow in the cavity exhibits a complex behavior. Typical distributions of the transverse velocity contours and kinetic energy fields at (Re=2000) have been obtained.

Numerical investigation of aerodynamic effects of opposite wrap-around fins at supersonic speeds

2018 ◽  
Vol 233 (7) ◽  
pp. 2410-2425 ◽  
Author(s):  
Amir Bagheri ◽  
Mahmoud Pasandidehfard ◽  
Seyed Ali Tavakoli Sabour
Keyword(s):  
Numerical Simulations ◽  
Research Work ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Opening Angle ◽  
Three Dimensional Flow ◽  
Rolling Moment ◽  
Drag Coefficients ◽  
Mach Numbers ◽  
Volume Method

In this research work, using numerical simulations, the three-dimensional flow around a standard projectile is investigated with two fin arrangement models, namely opposite and conventional wrap-around fins. Eliminating the rolling moment and investigation of aerodynamic performance of the new geometries are the purpose of this paper. Finite volume method is used to undertake the numerical simulations where flow is considered to be compressible, steady, nonviscous, and three-dimensional. For this purpose, the research begins with simulating the flow around a projectile with conventional fin arrangement and then the obtained values of drag coefficients and rolling moment are compared against experimental data, indicating the validity of the simulation results. After then, the effect of wrap-around fins in an opposite arrangement is investigated, with the results compared against those of the conventional configuration. The opposite fins are investigated at different opening angles and joint position, while the area of fins shading is assumed constant in all cases. Simulations were conducted at three Mach numbers of 1.5, 2.5, and 3.5, different angles of attack ranging within 0–14°, and lateral wind angles up to 8°. According to the results, the rolling moment in conventional wrap-around fins is a result of the pressure difference between sides of the fins, so that it can be avoided by configuring the fins in an opposite arrangement, which contributes to slightly higher drag coefficients too. Fin dimensions and their opening angle influence the regime of the flow passing through the fins, making their aerodynamic performance variable at different Mach numbers.

On End-Wall Corner Vortices in a Lid-Driven Cavity

1997 ◽  
Vol 119 (1) ◽  
pp. 201-204 ◽  
Author(s):  
T. P. Chiang ◽  
Robert R. Hwang ◽  
W. H. Sheu
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Fluid Flows ◽  
Solution Algorithm ◽  
Governing Equations ◽  
Cavity Depth ◽  
Driven Cavity ◽  
Volume Method ◽  
End Wall

We conducted a flow simulation to study the laminar flow in a three-dimensional rectangular cavity. The ratio of cavity depth to width is 1:1, and the span to width aspect ratio (SAR) is 3:1. The governing equations defined on staggered grids were solved in a transient context by using a finite volume method, in conjunction with a segregated solution algorithm. Of the most apparent manifestation of three-dimensional characteristics, we addressed in this study the formation of corner vortices and its role in aiding the transport of fluid flows in the primary eddy and the secondary eddies.

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