Explore the vast range of titles available.

The implementation of the wind turbine is a major issue in the wind engineering sector. However, the presence of wind turbines in the lower part of the atmospheric boundary layer (ABL) requires an appropriate study for the simulation of turbulent airflow in the wind farm situated on hilly terrain. The use of precise Computational Fluid Dynamics (CFD) simulations for the ABL flow is vital for numerous applications, such as wind energy, building, urban planning, etc. To achieve accurate results, it is imperative that the inlet boundary conditions produce vertical profiles that keep a uniform horizontal distribution (with no streamwise gradients) in the upstream region of the computational domain for all important parameters. A development approach is proposed herein, focused on the imposition of two different inlet profiles when used in combination with the rough z0-type scalable wall function. The horizontal homogeneity of these profiles has been verified by 2D Reynolds averaged Navier-Stokes (RANS) through the examination of a neutral ABL in an empty computational domain using the k-ε turbulence model. The findings indicate that the use of this modeling approach can yield relatively consistent homogeneity of neutral ABL for both inlet boundary conditions. Subsequently, sensitivity analyses were performed on the inflow profiles to forecast the evolution of the bottom half of an idealized truly-neutral ABL and to accurately capture the complex dynamics of atmospheric flows over hilly terrain. This study compares the results with the CRIACIV (Inter-University Research Centre on Building Aerodynamics and Wind Engineering) boundary layer wind tunnel experimental data, showing that the inflow profiles and the presence of topographic complex have a significant impact on air velocity, turbulent kinetic energy and turbulence intensity in the x-direction. The results obtained are in good correlation with published experimental data in the presence of the hill surface.

The determination of the wind loads of tensile membrane structures is of crucial importance during their design, since the extremely light weight of the structures can easily lead to severe wind effects on the doubly curved surfaces. According to the current state of the art, almost exclusively wind tunnel test is applied, which is the most reliable method today. On the other hand, the time and cost-consumption of the physical measurements, as well as the questions around the Reynolds number dependency of the wind loads, are serious bottlenecks of such an experimental method. Computational Fluid Dynamics offers an excellent and flexible tool to overcome such problems, but the currently available computational powers prevent the application of robust and high-fidelity scale-resolving methods. The paper deals with the Computational Wind Engineering-based determination of the mean wind loads on a doubly curved tensile membrane structure, applying the Reynolds-averaged Navier-Stokes framework. The conventional k-ω Shear Stress Transport and the recently developed generalized k-ω turbulence models are applied in the simulations. The latter model provides a set of tunable model parameters, where the modification of the coefficients is much clearer and straightforward compared to other turbulence closure models. By tuning the relevant parameter during the simulations, the second model provided significantly better results. The numerical results are validated against experimental data from previous wind tunnel measurements. The internal forces of the membrane in the principal directions of the orthotropic membrane material are computed, and the maximal values of the experimental and numerical-based distributions are compared.

This paper presents a computational fluid dynamics study of the evaluation of wind-flow field characteristics around arch-supported structures. The effectiveness of numerical simulations is validated through a detailed comparison with wind tunnel experimental data from the literature. The mean, spatial variation, maximum and minimum wind pressure coefficient distributions on different roof shape arch-supported structures (cusp, flat, and vaulted structures) were examined, and the investigation was extended by discussing different wind directions and various rise-span ratio structures. Results indicate that the wind pressure coefficient and turbulence disturbance on the cusp structure decrease significantly in magnitude compared with other structures. Structures experience relatively larger mean wind pressure coefficient with lower terrain roughness index. Furthermore, for a cusp structure, an increase in the rise-span ratio leads to the growth of wind pressure on the structure surface. In comparison with other wind directions, the roof surface is loaded with stronger negative wind pressure with an oblique wind direction of 45°. In particular, investigations on the effects of oblique wind directions and cusp-shaped structures on wind pressure and field need to be performed because they can be used for optimal engineering design.

The Yingxian Wooden Pagoda, a structure with a history spanning a thousand years, currently faces significant wind-induced safety risks. To understand the aerodynamic mechanism behind this issue, this study uses Computational Fluid Dynamics (CFD) with the Realizable k-ε turbulence model to perform high-fidelity transient simulations at wind speeds from 10 to 30 m per second. The results show that the highest positive pressure occurs on the sides of the windward face, while a large low-pressure vortex zone forms on the leeward side. The simulations include both the Kármán vortex street and the measurement of three-dimensional vortex-induced forces, marking a major advancement. A key finding is the synchronized period (ratio ≈ 1) of the along-wind and cross-wind forces, which differs from streamlined cylinders and is due to the pagoda’s unique octagonal shape. The force amplitudes increase exponentially with wind speed, while the average drag and lift have a quadratic relationship. Additionally, a new shape-specific correction factor of 0.875 is introduced to adjust the classical Strouhal formula, which greatly improves prediction accuracy for this type of ancient structure. This study offers both a theoretical foundation and a practical “digital wind tunnel” method for assessing wind-induced risks and supporting the safety monitoring of historic timber structures.

With wind power providing an increasing amount of electricity worldwide, the quantification of its spatio-temporal variations and the related uncertainty is crucial for energy planners and policy-makers. Here, we propose a methodological framework which (1) uses machine learning to reconstruct a spatio-temporal field of wind speed on a regular grid from spatially irregularly distributed measurements and (2) transforms the wind speed to wind power estimates. Estimates of both model and prediction uncertainties, and of their propagation after transforming wind speed to power, are provided without any assumptions on data distributions. The methodology is applied to study hourly wind power potential on a grid of 250×250 m2 for turbines of 100 m hub height in Switzerland, generating the first dataset of its type for the country. We show that the average annual power generation per turbine is 4.4 GWh. Results suggest that around 12,000 wind turbines could be installed on all 19,617 km2 of available area in Switzerland resulting in a maximum technical wind potential of 53 TWh. To achieve the Swiss expansion goals of wind power for 2050, around 1000 turbines would be sufficient, corresponding to only 8% of the maximum estimated potential.

Roof shape and slope are both important parameters for the safety of a structure, especially when facing wind loads. The present study demonstrates the pressure variations due to wind load on the pyramidal roof of a square plan low-rise building with 15% wall openings through CFD (Computational Fluid Dynamics) simulation. Many studies on roofed structures have been performed in the past; however, a detailed review of the literature indicates that the majority of these studies focused on flat, hip, gable and spherical roofs only. There is a lack of research that analyses these effects on pyramidal roof buildings. ANSYS (Analysis System) ICEM (Integrated Computer Engineering and Manufacturing)-CFD and ANSYS Fluent commercial packages have been used for modelling and simulation, respectively, and ANSYS CFD Post was used to obtain the results. A realizable k – ε turbulent model was used for the pressure distribution on the roof of the building model. In the present study, twenty-four models with different roof slopes ( α ), i.e. 0°, 10°, 20°, and 30°, with various wind incidence angles ( ϴ ), i.e. 0°, 15°, 30°, 45°, 60° and 75° were investigated. The influence of roof slope and wind incidence angle are analysed in this study. Results have been represented through pressure coefficient (Cp) contours on the roof surface and velocity streamlines of the flow field of the different cases. The optimization of the roof slope may be achieved by considering different wind incidence angles for buildings so that they may better withstand wind force in a specific area. When wind pressure coefficients from building models with openings were compared with pressure coefficients from building models without openings, it was found that the pressure coefficients for building models without openings are almost twice or three times that of the pressure coefficients for models with openings.

Mono-slope Canopy Roofs (MCRs) are prevalent in several locations, such as parking garages, shelters, bus terminals, restaurants, and agricultural facilities. The design of such structures is often tedious due to the lack of experimentation and literature available on wind codes. A detailed literature review observed that existing wind codes and standards give limited design recommendations for MCR. In contrast, this study examines the wind pressure distribution on MCR with varying roof slopes subjected to varying wind directions using wind tunnel testing and computational fluid dynamic (CFD) simulations. Experiments were performed to attain mean pressure distributions for roof slopes (0°, 15°, and 30°). Mutually coupled CFD simulations were performed for roof slopes ranging from 0° to 45° (@ 5° increments) and wind directions ranging from 0° to 180° (@ 30° increments) using the k-ε turbulence model. In terms of wind pressure coefficient, the CFD simulation results agreed well with the experimental results. It was observed that the flow pattern was significantly affected by the wind direction and roof slope of the MCR. The suction pressure was found to be critical on roof slopes (≤25°) under oblique wind directions (120° to 150°) due to the formation of conical vortices near the corner and side edges of the roof surface, however for MCR (≥25°) less suction pressure was observed. It is concluded that caution should be taken while considering the net pressure coefficient for designing low-sloped roofed structures, especially in windstorm-prone areas. The overall force coefficient and aerodynamic forces were found to be more prominent for higher roof slopes.

In the present study, the effect of installation of two-cylinder deflectors on the performance of Savonius wind turbine was investigated numerically using the computational fluid dynamics method. Hence, a stationary cylinder was mounted in front of the advancing blade to avoid the negative torque affecting the convex surface of the returning blade. Then, a second rotating cylinder was added to deviate the wind toward the advancing blade and to increase the efficiency of the rotor. The effect of cylinder diameter, angular velocity and deflector distance on torque and power coefficients, as well as the flow structure around the rotor, were studied. A two-dimensional incompressible unsteady Reynolds-averaged Navier–Stokes simulation in conjunction with the SST k − ω turbulence model was validated against available experimental data and then used for the studied configurations. A single stationary cylinder results in a maximal improvement of 10% of power coefficient. An improvement up to 97% was obtained by adding the rotating cylinder deflector at high angular velocity ( ω  = 30 rad/s). A low angular velocity of the rotating deflector ( ω  = 5 rad/s) requires less energy consumption and enhanced the performance of the Savonius by 18% at tip speed ratio TSR = 1.

Understanding wind pressure distribution on structures is crucial for evaluating design wind loads, especially for complex designs. This study investigated the wind pressure distribution on a windmill shape building with intricate geometries, i.e., the Chengdu Future Science and Technology City Exhibition Centre. Both wind tunnel test and CFD simulations are conducted to analyze the wind pressure distribution on building surface. Since the research object has intricate geometries, featuring sharp corners, curved surfaces, and ridges, the Reynolds Average Navier-Stokes (RANS) method adopting k-ε turbulence models is employed in the CFD simulations. Furthermore, scalable wall functions and non-structured grids with appropriate refinement on both turbulent regions and structural surfaces are also adopted in the RANS method. A comparison between the simulation results and wind tunnel tests demonstrated that the numerical simulations based on RANS method effectively capture surface wind pressure distribution on complex structures. This study reveals the occurrence of complicated flow phenomena that lead to a very complex wind pressure distribution on the surface of the structure, and drastic variance of the wind pressure coefficient is observed. Moreover, it is found that wind pressure distribution on the surface of the structure is highly sensitive to wind angle, exhibiting extreme negative pressure coefficients of −1.1, −1.0, and −1.8 at angles of 0°, 30°, and 60°, respectively. The analysis of the flow field around the structure at various wind angles reveals that its complex shape significantly alters the flow dynamics, creating distinct vortices and wake patterns at different angles. Consequently, CFD simulations help to understand wind loads on structures and improve wind resistance design.

Globally, wind energy is one of the most advanced sustainable power generation technologies, offering an environmentally friendly and cost-effective solution to meet the increasing demand for clean Energy. A critical factor in the successful conversion of wind energy is the utilization of wind turbine technology, and researchers continuously seek innovative designs to optimize wind turbines’ performance. Among the modern technologies developed for wind energy generation, Archimedes Screw Wind Turbine ( AScWT ) stands out as an advanced horizontal-axis turbine specifically designed for residential applications. This unique design aims to enhance energy collection while maintaining efficiency in lower wind conditions. The numerical analysis was carried out using Computational Fluid Dynamics ( CFD ) in ANSYS Fluent, employing the SST k–ω turbulence model under steady-state conditions to simulate the turbine’s performance. Through comprehensive parametric studies, the current research aimed to identify the optimal dimensions required to achieve maximum power coefficient ( C P max ). The study examined critical design variables, particularly the ratio between the inner and outer diameters ( d/D ), length ( L ), pitch ( P ), and inclination angle ( α ), to determine their impact on the turbine’s performance. The results revealed that ( d/D ) and (α) have the most significant influence on C P , whereas L and P had relatively minor effects. One of the key findings was that reducing the ( d/D) ratio could significantly increase the collected power by 209.8% at an inclination angle of 50º, and a wind speed of 2 m/s. Moreover, the best AScWT dimensions improved C Pmax by approximately 100.08% compared to the original design. These findings underscore the substantial potential of the AScWT design in improving wind energy efficiency, particularly for residential applications, rendering it a promising alternative for sustainable energy production in both urban and rural settings.