On the internal generation of waves: control volume approach

2011 ◽  
Vol 38 (8-9) ◽  
pp. 1027-1029 ◽  
Author(s):  
Gunwoo Kim ◽  
Myung Eun Lee
Keyword(s):  
Control Volume ◽  
Control Volume Approach ◽  
Internal Generation

A Control-Volume Model of the Compressible Euler Equations with a Vertical Lagrangian Coordinate

2013 ◽  
Vol 141 (7) ◽  
pp. 2526-2544 ◽  
Author(s):  
Xi Chen ◽  
Natalia Andronova ◽  
Bram Van Leer ◽  
Joyce E. Penner ◽  
John P. Boyd ◽  
...  
Keyword(s):  
Euler Equations ◽  
Control Volume ◽  
Test Cases ◽  
Riemann Solver ◽  
New Approach ◽  
Vertical Coordinate ◽  
Low Mach Number ◽  
Atmospheric Flows ◽  
Lagrangian Coordinate ◽  
Control Volume Approach

Abstract Accurate and stable numerical discretization of the equations for the nonhydrostatic atmosphere is required, for example, to resolve interactions between clouds and aerosols in the atmosphere. Here the authors present a modification of the hydrostatic control-volume approach for solving the nonhydrostatic Euler equations with a Lagrangian vertical coordinate. A scheme with low numerical diffusion is achieved by introducing a low Mach number approximate Riemann solver (LMARS) for atmospheric flows. LMARS is a flexible way to ensure stability for finite-volume numerical schemes in both Eulerian and vertical Lagrangian configurations. This new approach is validated on test cases using a 2D (x–z) configuration.

scholarly journals MODELING ATMOSPHERE COMPOSITION AND DETERMINING EXPLOSIBILITY IN A SEALED COAL MINE VOLUME

2014 ◽  
Vol 59 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Jianwei Cheng ◽  
Yi Luo
Keyword(s):  
Mathematical Model ◽  
Control Volume ◽  
Inert Gases ◽  
Mine Safety ◽  
Air Leakage ◽  
Gas Explosion ◽  
Triangle Diagram ◽  
Underground Coal Mines ◽  
Control Volume Approach ◽  
Explosion Risk

Abstract Explosions originated from or around the sealed areas in underground coal mines present a serious safety threat. The explosibility of the mine atmosphere depends on the composition of oxygen, combustible and inert gases. In additional, the composition in the inaccessible sealed areas change with time under various factors, such as gases emissions, air leakage, inert gases injected, etc. In order to improve mine safety, in this paper, a mathematical model based on the control volume approach to simulate the atmosphere compositions is developed, and the expanded Coward explosibility triangle diagram is used to assess the mine gas explosion risk. A computer program is developed to carry out the required computations and to display the results. In addition, the USBM explosibility diagram is also included in the program to serve as a double check.

Simulation of Turbulent Flow Through Hybrid Porous Medium: Clear Fluid Domains

2000 ◽  
Author(s):  
Marcelo J. S. de Lemos ◽  
Marcos H. J. Pedras
Keyword(s):  
Porous Medium ◽  
Turbulent Flow ◽  
Control Volume ◽  
Numerical Technique ◽  
Governing Equations ◽  
Clear Fluid ◽  
First Case ◽  
Flow Through ◽  
Control Volume Approach ◽  
Porous Obstacle

Abstract Turbulent flow in a channel, totally and partially filled with a porous medium, is simulated with a proposed turbulence model. Two cases are analyzed, namely clear flow past a porous obstacle and flow through a porous medium having a cavity with a higher porosity. Mean and turbulence quantities were solved within both computational domains using a single numerical technique. The control volume approach was used to discretize the governing equations. In the first case analyzed, the flow penetration into the porous substrate is accompanied by generation of turbulence kinetic energy within the obstacle. In the second geometry, the flow is pushed towards the cavity as porosity increases.

Free Convection in a Nanofluid Filled Square Cavity with an Horizontal Heated Plate

2011 ◽  
Vol 312-315 ◽  
pp. 433-438 ◽  
Author(s):  
Ali Akbar Abbasian Arani ◽  
Mostafa Mahmoodi ◽  
Meysam Amini
Keyword(s):  
Nusselt Number ◽  
Volume Fraction ◽  
Control Volume ◽  
Heated Plate ◽  
Square Cavity ◽  
Simpler Algorithm ◽  
Vertical Walls ◽  
The Mean ◽  
Energy Equations ◽  
Control Volume Approach

The natural convection in a square cavity with a heated horizontal plate containing a nanofluid (water and Ag) is simulated numerically. The heated plate and vertical walls are maintained at a constant temperature, Th and Tc, while the horizontal walls are adiabatic. The nanofluid is assumed to be incompressible and the flow is considered to be laminar. The continuity, momentum and energy equations written in terms of the primitive variables are discretized using a control volume approach and the SIMPLER algorithm. A parametric study is performed and the effect of the Rayleigh number, the location of the heated plate and the volume fraction of the nanoparticles on the fluid flow and the heat transfer inside the cavity are investigated. The results show that the mean Nusselt number of the vertical walls increases with increasing the volume fraction of the nanoparticles. Moreover, for a constant volume fraction of the nanoparticles, the Nusselt number of the vertical walls decreases substantially as the location of the heated plate varies from top to bottom of the cavity.

scholarly journals Mixed convection in a channel partially filled with metal foam blocks

2020 ◽  
Vol 330 ◽  
pp. 01044
Author(s):  
Syrine Khadhrawi ◽  
Fakhreddine Segni Oueslati ◽  
Rachid Bennacer
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Metal Foam ◽  
Control Volume ◽  
Velocity Fields ◽  
Flow Structures ◽  
Thermal Conductivity Ratio ◽  
Control Parameters ◽  
Energy Equations ◽  
Control Volume Approach

The present work is a numerical simulation of the mixed convection of an incompressible fluid in a horizontal channel under sun radiation partially filled with metal foam blocks. The Darcy-Brinkman model is adopted. The control volume approach is used to solve the motion and energy equations governing mixed convection. The study focuses on the effect of certain control parameters such as the Rayleigh number (Ra), the thermal conductivity ratio and the porosity on the flow structure and heat transfer. Indeed, the results for flow structures and temperature distribution are presented in the form of velocity fields with streamtraces and isotherms, while the average Nusselt number (Nu) is used to quantify heat transfer.

scholarly journals Viscous Flow and Dynamic Stall Effects on Vertical-Axis Wind Turbines

1995 ◽  
Vol 2 (1) ◽  
pp. 1-14 ◽  
Author(s):  
A. Allet ◽  
I. Paraschivoiu
Keyword(s):  
Wind Turbines ◽  
Stokes Equations ◽  
Control Volume ◽  
Numerical Procedure ◽  
Vertical Axis ◽  
Dynamic Stall ◽  
Staggered Grid ◽  
Speed Ratio ◽  
Vertical Axis Wind Turbines ◽  
Control Volume Approach

The present paper describes a numerical method, aimed to simulate the flow field of vertical-axis wind turbines, based on the solution of the steady, incompressible, laminar Navier-Stokes equations in cylindrical coordinates. The flow equations, written in conservation law form, are discretized using a control volume approach on a staggered grid. The effect of the spinning blades is simulated by distributing a time-averaged source terms in the ring of control volumes that lie in the path of turbine blades. The numerical procedure used here, based on the control volume approach, is the widely known “SIMPLER” algorithm. The resulting algebraic equations are solved by the TriDiagonal Matrix Algorithm (TDMA) in the r- and z-directions and the Cyclic TDMA in the 0-direction. The indicial model is used to simulate the effect of dynamic stall at low tip-speed ratio values. The viscous model, developed here, is used to predict aerodynamic loads and performance for the Sandia 17-m wind turbine. Predictions of the viscous model are compared with both experimental data and results from the CARDAAV aerodynamic code based on the Double-Multiple Streamtube Model. According to the experimental results, the analysis of local and global performance predictions by the 3D viscous model including dynamic stall effects shows a good improvement with respect to previous 2D models.

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