Understanding the persistence in time series is of crucial importance relating to the reliable forecast of wind speed. It has been widely acknowledged that fractal analysis is a useful tool to evaluate the persistence in wind speed time series using the fractal dimension (D) as a quantitative indicator. This paper aims to unveil the persistent characteristics of wind speed time series recorded under

Reducing train pantograph noise is particularly important. In this paper, the flow behaviour and noise contribution of simplified geometries representing high-speed train pantographs and the roof cavity at 1/10th scale are investigated. The Improved Delayed detached-Eddy Simulation (IDDES) turbulent model is used for the flow field simulation and the Ffowcs Williams & Hawkings aeroacoustic analogy

A series of experiments were carried out in a model-scale tunnel to investigate the confinement velocity in the tunnel fire with longitudinal ventilation. The significance of longitudinal ventilation to the smoke control in tunnel fire was comprehensively elaborated by both the variation of smoke back-layering length in the upstream and the characteristics of smoke layer in the downstream which was

Interference effects of tall buildings have attracted numerous studies due to the boom of clusters of buildings in megacities. To fully understand the interference effects, it often requires a substantial amount of wind tunnel tests. Limited wind tunnel tests that only cover part of interference scenarios are unable to fully reveal the interference effects. This study used machine learning techniques

Detailed studies on wind turbines have been attracting increasing attention in recent years in order to save fossil resources and protect the environment. Vertical axis wind turbines (VAWTs) are not as popular as horizontal axis wind turbines (HAWTs) because of their relatively low efficiency. Based on CFD approaches, this paper studies the influence of the aerofoil’s maximum camber as well as its

The use of rear cavities at the base of a square-back Ahmed body has been experimentally evaluated as a passive control device under cross-wind conditions with yaw angles β≤10°, by means of pressure, force and velocity measurements. A comparative study has been performed at a Reynolds number Re=105, considering the reference square-back body (i.e. the body without any passive control device), and the

Large eddy simulations (LES) are performed to examine the flow characteristics around solar arrays mounted on a flat-roof building for two oblique wind directions, 45° and 135°. The main purpose of this study is to clarify the mechanisms of some special features of wind pressure characteristics acting on solar panels obtained by wind tunnel experiments. Numerical simulation is first conducted for a

In this study, the torsional aeroelastic effects are investigated for high-rise buildings by carrying out a series of forced vibration wind tunnel tests. In these tests nine building models with different side ratios and structural eccentricities are considered, where the structural responses and surface pressures for each model are measured. The method used to determine the torsional aerodynamic stiffness

The effects of vertical splitter plates attached to the facades of high-rise building on the wind loads were investigated in details, based on a series of wind tunnel experiments. The rigid models with pressure taps were adopted, and totally one reference model and 16 models with different appurtenances configurations simulated by thin vertical splitter plates were studied. The testing results indicate

In this paper non-neutral approaching flows were employed in a meteorological wind tunnel on a regular urban-like array of rectangular buildings. As far as stable stratification is concerned, results on the flow above and inside the canopy show a clear reduction of the Reynolds stresses and an increment of the Monin-Obukhov length up to 80%. The roughness length and displacement height were also affected

This study identifies the modal parameters of four super high-rise buildings in Shenzhen and analyzes the variation of their structural dynamic properties with amplitude and time based on the long-term field data of Super Typhoon Mangkhut. Results show the maximum acceleration of the four buildings is 13.29–41.96 milli-g and occurs at the maximum wind speed period. In the early stage, as the wind speed

The Reynolds number effects on body limbs of a cyclist model, namely leg and arm, are investigated via robotic volumetric Particle Image Velocimetry measurements in the velocity range from 5 ​m/s to 25 ​m/s. The near wakes of such body limbs feature recirculation regions whose width and length are governed not only by the taper of the body parts, but also by the presence of coherent streamwise vortical

Wind actions are crucial for the safety and sustainability of structures. The wind climate of Europe and many other parts of the world is dominated by synoptic extra-tropical cyclones and mesoscale thunderstorms. Thunderstorms are frequent events that cause wind speeds and damage often greater than those of cyclones. This paper describes a wide research activity including an extensive monitoring network