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Investigation of flow and pressure characteristics around pyramidal buildings

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Book Series: Dissertationsreihe am Institut für Hydromechanik der Universität Karlsruhe (TH) ISSN: 14394111 ISBN: 3937300724 Year: Volume: 2005,3 Pages: XVI, 138 p. DOI: 10.5445/KSP/1000003455 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: General and Civil Engineering
Added to DOAB on : 2019-07-30 20:02:00
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Pyramidal buildings are undergoing a renaissance in todays architectural design due to their attractive mystery that has fascinated many architects. From an aerodynamic engineering point of view, structural buildings with the shape of a pyramid have their own interesting and particular aerodynamic characteristics as compared to other usual structural buildings (i.e. cuboidal).However, despite its distinct aerodynamic characteristics compared to other usual structural buildings, the flow and pressure characteristics around pyramidal structures have not yet been investigated completely. Very limited studies about pyramidal buildings can be found in the literature.Consequently, the technical layout with respect to wind load assumption of pyramidal buildings are usually not listed in standard tables which underlines the need of systematic investigations for pyramidal structures.In this study, pyramids with a wide range of base angle variation (theta = 30°, 40°, 45°, 50°, 55°, 60°, 70°) have been investigated intensively through a detailed and accurate laboratory experiments at the Laboratory of Building- and Environmental Aerodynamics, Institute for Hydromechanics, at the University of Karlsruhe. The flow measurements were performed using a 2-D Laser Doppler anemometry (LDA) and The pressure measurements were carried out using a standard pressure tapping technique. The present study focuses on the most important parameters affecting the flow and pressure characteristics that include the influence of base angles, the influence of wind directions and the influence of the pyramid heights with respect to a characteristic length. Besides the experimental investigations, numerical investigations with the aid of a software package called FLOVENT were also additionally performed in order to prove, whether experimental and numerical studies deliver the same results.Based on the flow measurement results, this study was able to distinguish the general characteristics of flow around pyramid building when compared to other type of structures (i.e. cuboidal structure). A set of equations to calculate the reattachment length at the leeward side of the pyramid was generated. In addition, an equation to estimate the zero streamline and an area below line as a function of the reattachment length and base angle, respectively, are proposed. These equations will illustrate the recirculation zone at the leeward side of the pyramid.The pressure measurement results show that the three investigated parameters (base angle, wind direction and pyramid height) have an important influence to the pressure characteristics (magnitude of pressure, suction and fluctuation) in the surfaces of the pyramids. For practical purposes, this study was able to provide the typical values of pressure and aerodynamic coefficients for pyramidal buildings that can be used for structural calculations. The values that are given in this study can be used to fill in the gap of the unavailable design values for pyramidal buildings in standard tables.

Wind Turbine Aerodynamics

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ISBN: 9783039215249 / 9783039215256 Year: Pages: 410 DOI: 10.3390/books978-3-03921-525-6 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-12-09 11:49:15
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Wind turbine aerodynamics is one of the central subjects of wind turbine technology. To reduce the levelized cost of energy (LCOE), the size of a single wind turbine has been increased to 12 MW at present, with further increases expected in the near future. Big wind turbines and their associated wind farms have many advantages but also challenges. The typical effects are mainly related to the increase in Reynolds number and blade flexibility. This Special Issue is a collection of 21 important research works addressing the aerodynamic challenges appearing in such developments. The 21 research papers cover a wide range of problems related to wind turbine aerodynamics, which includes atmospheric turbulent flow modeling, wind turbine flow modeling, wind turbine design, wind turbine control, wind farm flow modeling in complex terrain, wind turbine noise modeling, vertical axis wind turbine, and offshore wind energy. Readers from all over the globe are expected to greatly benefit from this Special Issue collection regarding their own work and the goal of enabling the technological development of new environmentally friendly and cost-effective wind energy systems in order to reach the target of 100% energy use from renewable sources, worldwide, by 2050

Keywords

H-type floating VAWT --- truss Spar floating foundation --- coupling of aerodynamics and hydrodynamics --- computational fluid dynamics --- wind farm --- complex terrain --- SCADA --- met mast measurements --- wind turbine --- simplified free vortex wake --- vortex ring --- aerodynamics --- axial steady condition --- variable pitch --- H-type VAWT --- straight blade --- DMST model --- NACA0012 --- wind energy --- power coefficient --- tip speed ratio --- wind turbine blade optimization --- computational fluid dynamic --- actuator disc --- wake effect --- Non-dominated Sorting Genetic Algorithm (NSGA-II) --- wind turbine airfoil --- dynamic stall --- boundary layer separation --- aerodynamic characteristics --- rotor blade optimization --- blade parametrization --- computational fluid dynamics --- OpenFOAM --- gradient-based --- adjoint approach --- wind turbine optimization --- low wind speed areas --- cost of energy --- particle swarm optimization --- dynamic stall --- pitch oscillation --- oscillating freestream --- rotational augmentation --- wind turbine --- turbulence --- super-statistics --- piezo-electric flow sensor --- ABL stability --- laminar-turbulent transition --- wind speed extrapolation --- atmospheric stability --- wind shear --- wind resource assessment --- wind turbine --- stall --- NREL Phase VI --- S809 airfoil --- MEXICO --- RANS --- wind turbine wakes --- turbulence --- actuator disk --- LES --- wind tunnel --- OpenFOAM --- wind turbine --- wind turbine design --- optimization --- blade length --- economic analysis --- typhoon --- wind turbine --- meso/microscale --- aerodynamic force --- mechanical performance --- thermography --- wind turbine blades --- defects --- image processing --- condition monitoring --- wind farm --- layout optimization --- design --- random search --- complex terrain --- airfoil design --- aerodynamic --- wind tunnel experiment --- VAWTs (Vertical axis wind turbines) --- computational fluid dynamics --- floating offshore wind turbine --- dynamic fluid body interaction --- semi-submersible platform --- OC5 DeepCWind --- wind turbine --- aerodynamics --- turbulent inflow --- Computational Fluid Dynamics --- blade element momentum theory --- actuator line method --- Fatigue Loads --- wind turbine noise source --- wind turbine noise propagation --- wind turbine wake --- n/a

Computational Aerodynamic Modeling of Aerospace Vehicles

Authors: ---
ISBN: 9783038976103 Year: Pages: 294 DOI: 10.3390/books978-3-03897-611-0 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering --- Transportation
Added to DOAB on : 2019-03-08 11:42:05
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Currently, the use of computational fluid dynamics (CFD) solutions is considered as the state-of-the-art in the modeling of unsteady nonlinear flow physics and offers an early and improved understanding of air vehicle aerodynamics and stability and control characteristics. This Special Issue covers recent computational efforts on simulation of aerospace vehicles including fighter aircraft, rotorcraft, propeller driven vehicles, unmanned vehicle, projectiles, and air drop configurations. The complex flow physics of these configurations pose significant challenges in CFD modeling. Some of these challenges include prediction of vortical flows and shock waves, rapid maneuvering aircraft with fast moving control surfaces, and interactions between propellers and wing, fluid and structure, boundary layer and shock waves. Additional topic of interest in this Special Issue is the use of CFD tools in aircraft design and flight mechanics. The problem with these applications is the computational cost involved, particularly if this is viewed as a brute-force calculation of vehicle’s aerodynamics through its flight envelope. To make progress in routinely using of CFD in aircraft design, methods based on sampling, model updating and system identification should be considered.

Keywords

wake --- bluff body --- square cylinder --- DDES --- URANS --- turbulence model --- large eddy simulation --- Taylor–Green vortex --- numerical dissipation --- modified equation analysis --- truncation error --- MUSCL --- dynamic Smagorinsky subgrid-scale model --- kinetic energy dissipation --- computational fluid dynamics (CFD) --- microfluidics --- numerical methods --- gasdynamics --- shock-channel --- microelectromechanical systems (MEMS) --- discontinuous Galerkin finite element method (DG–FEM) --- fluid mechanics --- characteristics-based scheme --- multi-directional --- Riemann solver --- Godunov method --- bifurcation --- wind tunnel --- neural networks --- modeling --- unsteady aerodynamic characteristics --- high angles of attack --- hypersonic --- wake --- chemistry --- slender-body --- angle of attack --- detection --- after-body --- S-duct diffuser --- flow distortion --- flow control --- vortex generators --- aeroelasticity --- reduced-order model --- flutter --- wind gust responses --- computational fluid dynamics --- convolution integral --- sharp-edge gust --- reduced order aerodynamic model --- geometry --- meshing --- aerodynamics --- CPACS --- MDO --- VLM --- Euler --- CFD --- variable fidelity --- multi-fidelity --- aerodynamic performance --- formation --- VLM --- RANS --- hybrid reduced-order model --- quasi-analytical --- aeroelasticity --- flexible wings --- subsonic --- wing–propeller aerodynamic interaction --- p-factor --- installed propeller --- overset grid approach

Engineering Fluid Dynamics 2018

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ISBN: 9783039281121 / 9783039281138 Year: Pages: 256 DOI: 10.3390/books978-3-03928-113-8 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: General and Civil Engineering --- Technology (General)
Added to DOAB on : 2020-01-30 16:39:46
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“Engineering Fluid Dynamics 2018”. The topic of engineering fluid dynamics includes both experimental as well as computational studies. Of special interest were submissions from the fields of mechanical, chemical, marine, safety, and energy engineering. We welcomed both original research articles as well as review articles. After one year, 28 papers were submitted and 14 were accepted for publication. The average processing time was 37.91 days. The authors had the following geographical distribution: China (9); Korea (3); Spain (1); and India (1). Papers covered a wide range of topics, including analysis of fans, turbines, fires in tunnels, vortex generators, deep sea mining, as well as pumps.

Keywords

axial fan --- rotating stall --- aerodynamic noise --- numerical simulation --- noise spectrum --- centrifugal pump --- radiation noise --- distribution characteristic --- acoustic energy --- experimental research --- thermosyphon --- volume of fluid --- multiphase flow --- evaporation and condensation --- centrifugal pump --- impeller --- blade wrap angle --- blade exit angle --- optimized design --- deep sea mining --- manganese nodules exploitation --- hydraulic collecting --- suction flow field --- dimensional analysis --- circumferential groove casing treatment --- sweep and lean --- CGCT-blade integrated optimization --- computational fluid dynamics (CFD) --- flow around cylinder --- fluid structure interaction (FSI) --- hydrodynamic response --- numerical methods --- simulation and modeling --- vortex induced vibration (VIV) ratio --- gas turbine --- axial gap --- hot streak --- heat transfer --- leading edge --- global optimization --- cavitation inception --- orthogonal test --- CFD simulation --- two-stage axial fan --- numerical simulation --- abnormal blade installation angle --- rotating stall --- Tesla turbine --- fluid dynamics --- disc thickness --- disc spacing distance --- isentropic efficiency --- plug-holing --- tunnel slope --- fire --- natural ventilation --- ventilation performance --- aspect ratio --- evacuation --- fire propagation --- tunnel vehicle fire --- unsteady heat release rate --- flow control --- vortex generators --- source term --- Computational Fluid Dynamics (CFD) --- OpenFOAM --- wind tunnel

Recent Advances in Urban Ventilation Assessment and Flow Modelling

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ISBN: 9783038978060 9783038978077 Year: Pages: 448 DOI: 10.3390/books978-3-03897-807-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General)
Added to DOAB on : 2019-04-25 16:37:17
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This book contains twenty-one original papers and one review paper published by internationally recognized experts in the Atmosphere Special Issue ""Recent Advances in Urban Ventilation Assessment and Flow Modelling"", years 2017–2019. The Special Issue includes contributions on recent experimental and modelling works, techniques, and developments mainly tailored to the assessment of urban ventilation on flow and pollutant dispersion in cities. The study of ventilation is of critical importance, as it addresses the capacity with which a built urban structure is capable of replacing the polluted air with ambient fresh air. Here, ventilation is recognized as a transport process that improves local microclimate and air quality and closely relates to the term “breathability”. The efficiency with which street canyon ventilation occurs depends on the complex interaction between the atmospheric boundary layer flow and the local urban morphology.The individual contributions to this Issue are summarized and categorized into four broad topics: (1) outdoor ventilation efficiency and application/development of ventilation indices, (2) relationship between indoor and outdoor ventilation, (3) effects of urban morphology and obstacles to ventilation, and (4) ventilation modelling in realistic urban districts. The results and approaches presented and proposed will be of great interest to experimentalists and modelers, and may constitute a starting point for the improvement of numerical simulations of flow and pollutant dispersion in the urban environment, for the development of simulation tools, and for the implementation of mitigation strategies.

Keywords

street canyon --- seasonal variation --- air flow --- pollutant dispersion --- pollutant removal --- natural ventilation --- residential wind environments --- building arrangements --- space pattern --- ventilation efficiency --- CFD simulation --- air change rate (ACH) --- flow and turbulence profiles --- hypothetical urban areas --- street-level ventilation --- ventilation assessment --- wind-tunnel dataset --- street vegetation --- CFD --- aerodynamic and deposition --- tree scenarios --- urban planning --- indoor-outdoor --- mass concentration --- nanoparticles --- particle number concentration (PNC) --- PM10 --- PM2.5 --- sampling --- Total Suspended Particles (TSP) --- ultrafine particles (UFP) --- urban street canyon --- wind enhancement --- architectural intervention --- water channel experiment --- CFD simulation --- passive ventilation --- street canyon --- computational fluid dynamics (CFD) --- ventilation effectiveness --- the age of air --- convective boundary layer --- LES --- street-level ventilation --- small open space --- air change rate per hour (ACH) --- concentration decay method --- urban age of air --- computational fluid dynamic (CFD) simulation --- natural ventilation --- residential building --- climate zone --- thermal comfort --- natural ventilation hour --- Japan cities --- building energy use --- inter-building effect --- highly-reflective building envelope --- BEopt analysis --- source apportionment --- data assimilation --- urban air quality modelling --- wind environment --- Natural Ventilation Potential (NVP) --- PM2.5 --- building–tree grouping patterns --- Computational Fluid Dynamics (CFD) --- LES --- ventilation --- urban planning --- dispersion --- air quality --- street canyon --- traffic tidal flow --- numerical simulation --- vehicular pollution --- non-uniform distribution of the pollution source --- on-road air quality --- traffic composition --- high emitting vehicles --- street canyon --- mobile laboratory --- CFD model --- heat loss --- optimisation --- residential building --- air quality --- carbon dioxide concentration --- ventilation system --- wind pressure coefficient --- airflow network --- multiple linear regression --- natural ventilation --- urban layout --- surrogate model --- schematic urban environment --- wind tunnel --- LES --- validation --- street canyon --- coherent structures --- road tunnel --- natural ventilation --- wind catcher --- intake fraction --- street canyon --- CFD --- Large Eddy Simulation (LES) --- urban air quality --- pedestrian exposure --- concentration fluctuation --- outdoor ventilation --- urban morphology --- building site coverage --- ventilation efficiency --- n/a

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