In this study, a numerical urban model is proposed, which includes digital elevation model for topography, land-use database, digital maps on buildings and vegetation. Turbulent flow fields in the cube arrays with different packing densities and a real urban area are investigated by both modified k−ε model and large eddy simulation (LES). It is found that the simulation with the modified k−ε model

The use of wind speed data recorded using different measuring equipment (i.e. anemometers with different response characteristics) and different signal-processing procedures can introduce errors in the characterisation of surface wind speeds. This study aims to assess the effects of a set of various moving average filter durations and turbulence intensities on the recorded maximum gust wind speeds

A direct-forcing immersed boundary (DFIB) method with a virtual force is used to investigate the vortex-induced vibration (VIV) of an elastically mounted sphere in uniform flow at a moderate Reynolds number. A novel method is investigated to control VIV of an elastically mounted sphere by placing a small fixed sphere inline in tandem arrangement. The numerical method is validated by comparisons with

A wind tunnel investigation into the effects of yaw on a track bicycle, ridden by an anatomically-accurate pedalling mannequin, is completed and the results are compared with on-track velodrome data. The results show that there is an amplification effect with a minor bicycle geometric yaw creating a major aerodynamic yaw anterior to the bicycle. The magnitude of this aerodynamic yaw angle amplification

Many circular cylindrical engineering structures submerged in fluid are not always orthogonal to flow direction. Oblique circular cylinder is a more general model to study the flow around circular cylindrical engineering structures. Comparing with a normal circular cylinder, there are more three-dimensional effects reflected in the wake flow and aerodynamic forces of an oblique circular cylinder. Moreover

Large negative peak pressures commonly take place near the edges of buildings due to the presence of local corner vortices and impingement of shear layers. As a result, Probability Density Functions (PDF) of the measured pressure signals exhibit one or more components which contributes to the non-Gaussianity of the pressure loading. These mixed flows can be modeled with mixture models. Whenever several

This study conducted a validation for the lattice Boltzmann method-based large-eddy simulation (LBM-LES) applied to flow around a single 1:1:2 building. The flow structures and distribution of time-averaged velocity and turbulent kinetic energy (TKE), particularly at pedestrian height, were examined against data obtained by an experiment and finite volume method-based LES (FVM-LES), in addition to

Large eddy simulations (LES) can provide a powerful tool for cladding design, but their accuracy strongly depends on the correct representation of the incoming atmospheric boundary layer (ABL). The objective of this work is to validate LES of a wind tunnel experiment of wind loading on a high-rise building, focusing on accounting for sensitivity to the incoming ABL. We define three uncertain parameters

Active control of flutter of a long span cable-stayed bridge is considered in this study. The control action is provided by winglets actuated using constant/variable gain output feedback controllers. Two FE modeling schemes are adopted, namely one element cables, and multi-element cables with each stay-cable discretized into multiple elements to consider the cable vibration effect. Cable discretization

The positive effects of a split on the aerodynamic performance of fixed wings are well known. However, for horizontal axis wind turbines (HAWTs), changes in the local angle of attack (AoA) and relative velocities along the blade create complex three-dimensional flow over blades, making the analysis of the split location very challenging. In this paper, the effects of the radial position of a split

Owing to continuous improvement in train running speeds, braking safety has become increasingly important, challenging braking approaches such as adhesion, eddy current, and electric magnet wheel brakes. Aerodynamic braking is an effective braking supplement whose braking effect is particularly outstanding in trains running at high speed. However, the flow field around the train can be significantly

Wind-tunnel experiments were conducted on an elongated bluff body to investigate the effects of leading-edge separation on its vortex shedding and aerodynamic characteristics. Solid wind barriers of various heights were fixed at the leading edge to adjust the flow separation and reattachment. The flow field, particularly the upper-surface boundary layer, was investigated by employing a high-resolution

This paper examines compact debris flight in tornado-like flow fields. The research focuses on physically simulating a specific tornado-like vortex and on investigating windborne debris flight with and without a low-rise building model. The low-rise building model, 1/8th scale with regard to the vortex core radius, was used to initiate the flight of Styrofoam spheres from its top. Debris motion was

The paper reviews the wind loading of buildings from a code perspective. The Canadian wind load provisions for buildings, due primarily to the ingenuity of Alan G. Davenport, have gained an international reputation after recognition for their innovative and pioneering character by researchers and practitioners across the globe. In this regard, these provisions have been influential in the development

Two vertical-axis wind turbines (VAWTs) benefit from a power increase when placed side by side in close proximity. To study the potential of paired VAWTs for integration in wind farms, wind tunnel wake measurements of lift-driven VAWTs are compared for isolated and three counter-rotating configurations. Because the wake of an isolated VAWT is deflected, the direction of rotation significantly influences

In wind-resistant designs of high-rise buildings, wind profiles are modeled for strong wind, where atmospheric stability is assumed to be neutral. When wind profiles are modeled from the results of short-term observations, which include few data on strong wind, a method to evaluate atmospheric stability and detect wind profiles under neutral conditions is required. In the present study, the applicability

Vertical-axis wind turbines have great potential for harvesting energy with high conversion efficiency both in small-scale distributed installations and in the emerging floating offshore technology; nevertheless, their complex unsteady flow field makes design and optimization very challenging. This paper documents an extensive CFD study on a H-shaped VAWT over the entire range of operation. First,

In general, motion-induced vortex vibration is considered to be caused by the unification of the separated vortex from leading edge and the secondary vortex at trailing edge. However, the results of previous wind tunnel tests for rectangular cross sections with side ratios of B/D ​= ​2, 4, 6 (B: along-wind length, D: cross-wind length) reveal that in the heaving mode, the secondary vortex at trailing

Design wind pressures for components and cladding (C&C) are key design parameters. For mid- and high-rise buildings, design pressures for C&C are often evaluated from wind tunnel tests, especially when building geometries are irregular or surrounding environments are complex. Wind tunnel data acquisition and analysis approaches both contribute to uncertainties of predicted design wind pressure coefficients

Due to the blunt aerodynamic configuration, the edge-girder bridge deck may sustain severe vortex-induced vibrations (VIVs) that adversely affect bridge usability and security. In the present study, the VIV performance and the related aerodynamic mechanism of the two-box edge girder for a cable-stayed bridge are systematically investigated. Based on the flow pattern and vortex structure around the

A novel opto-mechanical platform to measure the dynamic response of a multi-megawatt wind turbine is developed and applied. This opto-mechanical platform measures the blade shape, blade deflections and characteristics of blade vibrations by tracking blade during operation without need for any modification or attachment to the turbine. Simultaneous measurements of the wind speed, wind direction, and

Indented surface grooves can eliminate the laminar separation bubbles formed on airfoil surfaces, and thus have the potential to improve the aerodynamic performance of small wind turbines. In this study, a three-equation transitional turbulence model was selected and validated with experimental data to simulate the 2D flow around a NACA 4415 airfoil. Parametric simulation of surface groove characteristics

The interaction of a wing-tip vortex of a rectangular, square-tipped wing having a NACA 0012 airfoil section with a grid-generated turbulent flow was investigated in this paper. The experiments were conducted in the near and mid-wake regions at three free stream turbulence (FST) intensities of 0.5%, 3% and 6%, and at two Reynolds numbers, Re, based on the wing chord length, cw, of 2×105 and 3×105.

Polynomial-type mathematical models were presented to describe the nonlinear self-excited forces of nonlinear single degree of freedom (SDOF) torsional flutter of bluff bridge decks and nonlinear coupled flutter of streamline-like flat closed box bridge decks. A full bridge analysis method for nonlinear SDOF torsional flutter of long span bridges with bluff decks was then proposed based on the aeroelastic

The dynamic complexity and the limited spatiotemporal structure of thunderstorms make the collection of reliable and systematic measurements of this phenomenon, which are definitely needed to evaluate its action on structures, challenging. The Northern Tyrrhenian is a “hot-spot” for the genesis of severe potentially damaging wind phenomena, such as downbursts. In the context of the European projects

Uncertainties associated with aerodynamic properties of wind turbine blades, such as the lift coefficient and its first derivative with respect to the angle of attack, measured in the wind tunnel, are not negligible. Uncertainties are due to random experimental laboratory errors. Uncertainties are examined by high frequency force balance tests in Northeastern University's wind tunnel. Experiments are

On the basis of the wind records from 356-m-high Shenzhen Meteorological Gradient Tower (SZMGT) which is the tallest of its kind in Asia, this paper presents an observational study of wind characteristics during Super Typhoon Mangkhut and aims to enhance the understanding of the boundary layer wind structure of strong typhoons over land. First of all, the raw records are selected for subsequent analysis

The effect of varying the aspect ratio of a 1:8 scaled Ground Transportation System (GTS) was numerically investigated using the steady formulation of the RANS k−ω SST model. Cases of different aspect ratios (defined as the ratio of the varying width to the baseline width (Eq. (1)), with and without a boat-tail, were considered. For the GTS without boat-tail, a quasi-linear decline in the drag coefficient

This paper presents a study on the turbulent structure of the wind velocity field around a rectangular prism building model, calculated using large-eddy simulation. Spectral proper orthogonal decomposition (SPOD), a technique to perform proper orthogonal decomposition (POD) in the frequency domain, was applied to extract the physical phenomenon with the largest kinetic energy from the velocity field

The introduction of the Harmonized Light Vehicles Test Procedure causes a significant challenge for the automotive industry, as it increases the importance of efficient aerodynamics and demands how variations of optional extras affect the car’s fuel consumption and emissions. This may lead to a huge number of combinations of optional extras that may need to be aerodynamically analyzed and possibly

Based on the statistical results of field investigations of stay cable shapes, the deformed cross-sections tend to be micro-elliptical. These deformations may significantly influence the aerodynamic forces and vibration characteristics of stay cables. Accordingly, the aerodynamic forces and wind-induced vibrations of stay cables with circular and various micro-elliptical sections are measured in wind

Renewable energy has taken a center stage in sustainable and environmentally safe power generation. In this work, a novel model free Reinforcement Learning based wind speed forecasting technique has been proposed. Our technique uses modified fuzzy Q learning (MFQL) framework to accurately predict 1-min ahead wind speed from the publicly available data online. Empirical Mode Decomposition (EMD) and

The paper outlines a set of experimental criteria implemented to examine the influence of geometric scale on wind-induced pressures on roof-mounted solar panels tested in a simulated atmospheric boundary layer. The results of this research contribute significantly to the understanding of the obstacles hindering the reliable evaluation of wind loads on solar panels, bearing in mind that the size of

Accidents, such as deflections, side slips, and even rolls, can easily occur when road vehicles moving on the bridge deck at high speed are subjected to sudden changes owing to strong crosswinds. Wind barriers are an effective way to ensure the driving safety of vehicles on the bridge but with potential negative influences on the aerodynamic performance. Therefore, it is critical to evaluate the shielding

This paper presents wind pressure distribution characteristics of oval-shaped arch-supported membrane structures based on the wind tunnel experiments. Distribution of mean and fluctuating wind pressure coefficient is presented meticulously using pressure maps. Influence of different factors including rise-span ratio, wind direction, and terrain category, on the distribution of mean, fluctuating and

Wind tunnel tests on models of a 1000 ​kV super high-rise tubular steel transmission tower were carried out under two wind fields. In order that the boundary conditions for the tower section models be consistent with those of the actual structure, a new experimental method is proposed. The results show the drag coefficients in a thick turbulent boundary layer are generally less than those in uniform

Aerodynamic forces on a slender prism are frequently estimated by conventional measurements using rigid models, thus the characteristics of unsteady aerodynamic forces inherent to an aeroelastic prism often remain unclear. Erected upon empirical results measured from aeroelastic, forced vibration and rigid models, this work supplies a holistic investigation on the characteristics of unsteady aerodynamic

This study deals with the effects of wind turbulence on the mean aerodynamic drag, lift and moment coefficients of a stationary ice-accreted section model of a bridge cable for different wind angles of attack. The experiments were conducted in the Reynolds number range between 2.5·104 and 1.36·105. While the yawed/inclined cable model was experimentally iced in a climatic wind tunnel, the development

This study applies the Dynamic Mode Decomposition (DMD) technique to a prototypical wind engineering problem of flow past a square prism at a Reynolds number of 22,000 to investigate the DMD’s accuracy and practical values in pressure flow field analysis. In reconstructing the original pressure field obtained by Large-Eddy-Simulations (LES), a full-order DMD model achieves a stellar accuracy within

Flow conditions in complex terrains such as fjords are highly three-dimensional and thus not properly captured by the wind flow models developed for homogenous terrains. In the present study, we explore the potential of computational fluid dynamics (CFD) simulations relying on the steady 3D Reynolds-averaged Navier-Stokes equations to complement in-situ measurements from a long-span bridge in a narrow

Appropriate design wind loads can effectively avoid damage to transmission towers under strong wind and the wind-induced vibration coefficient β(z) is a critical parameter for determining those loads. Based on the inertial load approach, a step-by-step calculation method for the design wind loads of transmission towers considering the effects of cross-arms and diaphragms was proposed. In order to be

This article focuses on experimental investigation of the interaction between downburst (DB) and near-surface atmospheric boundary layer (ABL) winds. The flow field of DB immersed into ABL winds (DBABL) is compared against the outflow produced by an isolated DB without ABL winds. The diameter of investigated downdrafts was 3.2 ​m. The study demonstrates that there is a profound difference between the

In this study, we analyse the unsteady flow around a 1/8th-scaled uniform vehicle model with three configurations of aerodynamic braking plates mounted at the inter-carriage region. In addition, the study aims at determining an appropriate plate configuration to obtain an increasing effect of aerodynamic drag and analyses the effect of plates on the flow field at the top of the vehicle, where a pantograph

The wind loads of two chimneys with different distances and incident angles were obtained by pressure measurement tests, and the results were presented as interfering factor (IF) contours. The interference effects on the across-wind loads were significantly greater than those on the along-wind loads. The dynamic responses of the chimney were calculated using the frequency domain method, and the extreme

Atmospheric boundary layer (ABL) is generated due to frictions induced by obstacles on the Earth’s surface, such as terrains, vegetation, buildings, etc … Inspired by this physical mechanism, horizontally homogeneous ABL flow in computational fluid dynamics is achieved by proposing an enriched canopy drag (ECD) model, which is more flexible in reproducing the effects of various physical roughness ground

Observing wind loads directly in model scale is an effective way to predict extreme loads from the tail of the wind pressure distribution, but to ensure the reliability of the predictions, long-term data may be necessary. Such data are expensive in a wind tunnel. In this study, a criterion is established for dividing a short-term wind pressure sample into independent sub-samples. The observation duration

This paper concentrates on the interaction of a car body with the surrounding airflow, in order to provide small changes for reducing vehicle fuel consumption by reducing drag. There are many passive and active methods for this purpose, the main goal of this project is the development of passive drag reduction devices for the simplified reference model (Ahmed body with 25°, 30°, and 35° slant angle)

Photovoltaic (PV) modules are mainly mounted on the ground and on roofs. Recently, cable-supported PV modules have been proposed to replace traditional beams using suspension cables to bear the loads of the PV modules. These modules have a long span, are lightweight, can bear strong loads, can be adapted to complex terrains, and provide an excellent supplement to traditional structures in special sites

Discretely distributed side-surface openings have a stabilizing effect on box girders against galloping. This research intends to further investigate the relationship between the size of the openings and galloping instability with respect to aerodynamic response and aerodynamic damping. An additional objective is to explain the stabilization mechanism against galloping owing to the openings. A series

The performance of a long-span bridge under strong wind and traffic loads is of great importance to ensure the functionality and the serviceability of the bridge as well as the safety of running vehicles. In this paper, an innovative wind-traffic-bridge (WTB) interaction model for predicting the dynamic performance of the long-span bridge and running vehicles under the crosswind is proposed, considering

Data reconstruction is an important research topic for missing data recovery and data supplement. Spatial interpolation is often used for data reconstruction. The interpolation for time series is usually conducted at each time point by common methods, which is sometimes inefficient. Additionally, statistical characteristics recovering may not be taken into account together during interpolation, which

In this paper, the flight characteristics of plate-type windborne debris are examined by the CFD numerical simulation method taking account of two-way fluid-structure interaction (FSI) between the plate debris and the wind field. Two kinds of plates with different sizes and masses are selected as the research objects, and the SST k-ω turbulent model based on the RANS method is used to solve the flow

Due to the aerodynamic interference of two closely-spaced linked high-rise buildings, large out-of-phase vibrations of two buildings may be induced at across-wind direction. Tuned mass-damper-inerter (TMDI) is employed to mitigate wind-induced responses of the linked buildings. The linked buildings with TMDI takes advantage of the large relative motion between the two terminals of the inerter to reduce

An effective way to increase the volume of cargo transported by freight trains is to increase their operational speed. The complex flow generated by trains moving through air has attracted much attention from researchers aiming to further improve their performance. Unfortunately, wind tunnel tests do not fully represent the complex geometries and realistic flow conditions observed at full scale (wind

This paper analyses predictions from Large Eddy Simulations of a section of a double-stacked freight train subjected to various local loading configurations under the influence of cross-wind. In particular, drag, side force and moment coefficients of double-stacked containers on a test wagon were predicted for different combinations of upstream and downstream gaps between neighbouring wagons. The mean

Applications and prospects of Computational Fluid Dynamics (CFD) for wind engineering fields are described from the viewpoint of a researcher at a construction company. First, CFD applications for environmental tasks are introduced. Predicting the pedestrian wind environment was one of the earliest examples that was put into practical use. Since then, CFD has been extended to applications such as predicting

An experimental investigation was conducted to examine the effects of helical fillets on dynamic ice accretion process over the surfaces of bridge stay cables and evaluate its effects on the aerodynamic characteristics of the stay cables under both dry rime and wet glaze icing conditions. The experimental study was performed in the Icing Research Tunnel of Iowa State University (i.e., ISU-IRT). Four

Wind load assessment on the CAARC building with surrounding buildings is investigated employing Experimental and Digital Wind Tunnel tests for five wind angles of attack. The Digital Wind Tunnel simulations employ Large Eddy Simulation with a precursor database model as inlet boundary conditions. The façade loads are evaluated for the mean, fluctuating, minimum and maximum pressure coefficients, showing

This study presents a new approach for identification of nonlinear aerodynamic damping of wind-excited flexible structures from stochastic response time history that can be modeled as the output of a single-degree-of-freedom system under a white noise excitation. The amplitude-dependent aerodynamic damping ratio is described as a polynomial function of vibration displacement or velocity. Based on the

The experiences and contributions of the author over nearly 50 years in wind engineering are described. These cover the development of wind tunnel testing techniques and measurement methods as well as practical experiences on tall buildings, bridges, large span roofs, and research into small structures. The aerodynamics of tall buildings has emerged as critical to the design of the new generation of