Predicting far-lee wind flow characteristics behind a 2D wedge-shaped obstacle: Experiments, numerical simulations and empirical equations

2021 ◽  
Vol 194 ◽  
pp. 107673
Author(s):  
Junwei Lyu ◽  
Matthew S. Mason ◽  
Chien Ming Wang
Keyword(s):  
Numerical Simulations ◽  
Flow Characteristics ◽  
Wind Flow ◽  
Empirical Equations

scholarly journals Analytical and Numerical Feasibility Analysis of a Contra-Rotary Ramjet Engine

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 163
Author(s):  
Tomasz Laube ◽  
Janusz Piechna
Keyword(s):  
Numerical Simulations ◽  
Stokes Equations ◽  
Analytical Data ◽  
Combustion Process ◽  
Flow Characteristics ◽  
Combustion Model ◽  
Similar Data ◽  
High Rotational Speed ◽  
Jet Engine ◽  
Ramjet Engine

A new idea for a contra-rotary ramjet engine is presented. To define the theoretical limits of the non-typical, contra-rotary ramjet engine configuration, its analytical model was developed. The results obtained from that model and the analytical results were compared with those received from numerical simulations. The main weakness of existing rotary ramjet engine projects is the very high rotational speed of the rotor required for achieving supersonic inlet flow. In this paper, a new idea for a contra-rotary ramjet engine (CORRE) is presented and analyzed. This paper presents the results of analytical analysis and numerical simulations of a jet engine system with two rotors rotating in opposite directions. Contra-rotating rotors generate a supersonic air velocity at the inlet to the compressor at two times slower rotor’s speed. To determine the flow characteristics, combustion process, and engine efficiency of the double-rotor engine, a numerical solution of the average Navier-Stokes equations was used with the k-eps turbulence model and the non-premixed combustion model. The results of numerical simulations of flow and the combustion process inside the contra-rotary jet engine achieving a shockwave compression are shown and compared with similar data for a single-rotor engine design and analytical data. This paper presents only the calculation results of the flow processes and the combustion process, indicating the advantages of the proposed double-rotor design. The results of the numerical analysis were presented on the contours and diagrams of the pressure and flow velocity, temperature distribution, and mass fraction of the fuel.

scholarly journals Study the effect of angle of attack on flow characteristics at racing bike helmet using CFD

2018 ◽  
Vol 204 ◽  
pp. 06001
Author(s):  
Syamsuri ◽  
M Hasan Syafik ◽  
Yudho Putro Iswanto
Keyword(s):  
Numerical Simulations ◽  
Drag Coefficient ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Flow Characteristics ◽  
Reynold Number ◽  
Attack Angle ◽  
Large Area ◽  
Drag Racing ◽  
Simulation Results

At a cyclist drag racing champions greatly affect the speed of the bike, especially on the use of racing bike helmets. If the aerodynamic force from the racing bike helmet is getting smaller than the use of helmets on the bike racing will be more optimal and will affect the rate of the racer. In this study, numerical simulations were used to investigate the magnitude of the drag force that occurs around the surface of the helmet. With CFD software, 4 variations of attack angle 0°, 10°, 20° and 30° and variations of Reynold number 7.14x104, 1.00x105, and 1.16x105 are simulated to determine the flow characteristics of each state. The simulation results show that large area vortex is formed at the bottom of the helmet curve and dominates at the attack angle 30°. The result of the drag coefficient generated at the angle of attack 0° to 20° tends to decrease but at the attack angle 200 and 30° the drag coefficient increases.

The Wind Flow Characteristics Measuring Simulations of Soundproof Tunnels on Expressways

2018 ◽  
Vol 878 ◽  
pp. 70-75 ◽  
Author(s):  
Jang Youl You ◽  
Sun Young Paek ◽  
Doo Kie Kim ◽  
Ki Pyo You
Keyword(s):  
Wind Velocity ◽  
Flow Characteristics ◽  
Wind Flow ◽  
Cfd Analysis ◽  
Analysis Method ◽  
Residential Areas ◽  
Heat Islands ◽  
Computational Fluid Dynamics Cfd ◽  
Weather Stations ◽  
Using Data

Soundproof tunnels and soundproof walls constructed on expressways are designed to prevent noise for the nearby surrounding residential areas. These soundproof walls and tunnels feature excellent noise prevention for residential areas nearby, but they hamper the dispersion of air pollutants generated, thus promoting the creation of heat islands during summer and cold islands during winter.The computational fluid dynamics (CFD) analysis method was used to investigate the wind flow around soundproof tunnels. The wind angle and the size of the wind velocity were determined using data from weather stations near soundproof tunnels. The CFD analysis results of the soundproof tunnels on expressways revealed that the wind velocity decreased by 30–60% following the installation of soundproof tunnels.

Wind flow characteristics and their loading effects on flat roofs of low-rise buildings

2002 ◽  
Vol 5 (1) ◽  
pp. 25-48 ◽  
Author(s):  
Zhongshan Zhao ◽  
Partha P. Sarkar ◽  
Kishor C. Mehta ◽  
Fuqiang Wu
Keyword(s):  
Flow Characteristics ◽  
Wind Flow ◽  
Loading Effects ◽  
Flat Roofs

Flow Characteristics of Rarified Gases in Micro-Grooved Channels by the Lattice-Boltzmann Method

2008 ◽  
Author(s):  
Amador M. Guzma´n ◽  
Andre´s J. Di´az ◽  
Luis E. Sanhueza ◽  
Rodrigo A. Escobar
Keyword(s):  
Numerical Simulations ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Pressure Ratio ◽  
Plane Channel ◽  
Flow Characteristics ◽  
Numerical Results ◽  
Knudsen Numbers ◽  
Channel Configuration ◽  
Boltzmann Method

The flow characteristics of a rarified gas have been investigated in microgrooved channels. The governing Boltzmann Transport Equation (BTE) is solved by the Lattice-Boltzmann method (LBM) for the Knudsen number range of 0.01–0.1. First, the compressibility and rarified effects are investigated in a plane channel by performing numerical simulations for different Knudsen numbers, pressure ratio and accommodation coefficients with the objective of validating the computational code used in this investigation and determining the transition characteristics from the macro to microscale. The numerical predictions are compared to existing analytical and numerical results. Then, numerical simulations are performed for microgrooved channels for the Knudsen numbers range of [0.01–0.1]. Different meshes are used for preserving numerical stabilities and obtaining accurate enough numerical results. For the microgrooved channel configuration, the fluid characteristics are determined in terms of pressure ratio and Knudsen numbers. The numerical results are compared to existing analytical predictions and numerical results obtained from plane channel and one cavity simulations.

Wind flow and wind loads on the surface of a towershaped building: Numerical simulations and wind tunnel experiment

2008 ◽  
Vol 51 (1) ◽  
pp. 103-113
Author(s):  
YuJun Jiang ◽  
HuiZhi Liu ◽  
BoYin Zhang ◽  
FengRong Zhu ◽  
Bin Liang ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Numerical Simulations ◽  
Wind Tunnel Experiment ◽  
Wind Loads ◽  
Wind Flow

Flow Field Numerical Simulation on a Continuous Powder Surface Modifying Machine for Non-Metallic Material

2012 ◽  
Vol 246-247 ◽  
pp. 355-359
Author(s):  
Cui Ping Wu ◽  
Shui Lin Zheng ◽  
Jian Jun Luo
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Two Phase Flow ◽  
Concentration Field ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Mechanism Study ◽  
Two Phase ◽  
Metallic Material ◽  
Powder Surface

In order to study the two-phase flow field in the SLG continuous powder surface modifying machine for non-metallic material, which have been widely used in the powder engineering of China, a three-dimensional CFD model is developed to make the numerical simulations of the inner gas-particle flow field based on the industrial SLG-3/600 type modifying machine. By the help of the Fluent software, the gas velocity field, pressure field, particle concentration field and moving trace of the two-phase flow field are obtained. The simulation results indicate that these fields are distributed non-uniformly in the SLG modifying machine. Besides, a shortcut phenomenon is observed during the moving of the particles. The numerical simulations can not only depict the flow characteristics inside the SLG modifying machine, but also present useful reference to the mechanism study and optimal design to further improve its structure and working parameters in the future.

scholarly journals Study of Pressure Distribution on an Irregular Octagonal Plan Oval-Shape Building Using CFD

2021 ◽  
Vol 7 (10) ◽  
pp. 1787-1805
Author(s):  
Arun Kumar ◽  
Ritu Raj
Keyword(s):  
Pressure Distribution ◽  
Natural Ventilation ◽  
Open Space ◽  
Flow Characteristics ◽  
Wind Pressure ◽  
Wind Flow ◽  
Steady State Flow ◽  
Building Model ◽  
Ansys Cfx ◽  
Oval Shape

This paper aims to study the wind flow characteristics and to analyze the wind pressure distribution on the surfaces around an irregular octagonal plan shape building model. There is a central open space in plan to provide more surface area around the building for natural ventilation. Plan area of the building is 300 m2(excluding the open space) and height is 50 m. Steady state flow of wind with 5% turbulence (moderate turbulence) under atmospheric boundary layer has been taken in the study. Numerical simulation with standard k-e model using ANSYS (CFX) software has been used for the purpose. Flow characteristics has been studied in terms of flow separation, reattachment of flow, creation of wakes and vortices. The surface pressure generated around the model has been studied in terms of coefficient of pressure. The model is symmetrical about both the axes in plan. Hence, study for different wind angle of attacks from 0° to 90° @ 30° interval has been conducted. The flow characteristics and unusual or critical coefficient of pressure on surfaces of the model observed have been discussed. Doi: 10.28991/cej-2021-03091760 Full Text: PDF

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