Wind Effects Research Articles

The Impact of Weather on the Spread of COVID-19: The Case of the Two Largest Cities in Greece

The new global pandemic of COVID-19, declared on 11 March 2020 by the World Health Organization, has already had an unprecedented impact on health and socioeconomic activities worldwide. The second wave of the COVID-19 pandemic swept through the United States of America and Europe in late September 2020. Compared with other southern countries, such as Greece, where there was a significant increase in cases at the end of October 2020, Northern European countries (Germany, France, Austria, Finland, and Sweden) experienced this second wave of the pandemic earlier in September 2020. To understand the epidemiological behavior of the virus from an environmental perspective, we examined the effects of air temperature, humidity, and wind on the spread of COVID-19 in two of the largest population Regional Units (R.U.) of Greece, namely the R.U. of the Central Sector of Athens in Central Greece and the R.U. of Thessaloniki in Northern Greece. We applied Pearson correlation analysis and generalized linear models (GLM) with confirmed COVID-19 Intensive Care Unit (ICU) admissions from the National Public Health Organization as dependent variables and the corresponding air temperature, humidity, and wind speed from the Greek National Meteorological Service as independent covariates. The study focused on the period from 4 May 2020 to 3 November 2020 to investigate the impact of weather on the spread of COVID-19, in a period where human activities had partially returned to normal after the gradual lifting of the restrictive measures of the first lockdown (23 March 2020). The end date of the study period was set as the date of imposition of a new local lockdown in the R.U. of Thessaloniki (3 November 2020). Our findings showed that COVID-19 ICU admissions in both Regional Units decreased significantly with the temperature (T) and wind speed (WS) increase. In the R.U. of the Central Sector of Athens, this picture is reflected in both the single and cumulative lag effects of meteorological parameters. In the R.U. of Thessaloniki, this correlation was differentiated only in terms of the cumulative lag effect of the average daily temperature, where an increase (+17.6%) in daily confirmed COVID-19 ICU admissions was observed. On the other hand, relative humidity (RH) was significantly associated with an increase in cases in both R.U. This study, in addition to its contribution to the global research effort to understand the effects of weather on the spread of COVID-19, aims to highlight the need to integrate meteorological parameters as predictive factors in surveillance and early warning systems for infectious diseases. The combination of weather and climate factors (e.g., humidity, temperature, wind) and other contagious disease surveillance indicators (e.g., wastewater, geographic and population data, human activities) would make the early identification of potential epidemic risks more effective and would contribute to the immediate initiation of public health interventions and the more rational allocation of resources.

Characterizing wind, wave, and Stokes drift interactions in the upper ocean during Typhoon Doksuri using the COAWST model

The COAWST model is used in this study to simulate wind fields, wave fields, and Stokes drift during Typhoon Doksuri, aiming to reveal the dynamics of atmosphere-ocean-wave interactions under typhoon conditions. The COAWST model provides a more accurate simulation of typhoon wind speeds compared to ERA5 reanalysis data and the WRF model, and it offers a more precise representation of significant wave heights (Hs) than ERA5 reanalysis data and the SWAN model. The root mean square error (RMSE) of wind speed shows a reduction of 90.97% and 61.09% compared to ERA5 and WRF, respectively, resulting in an RMSE of 1.71 m/s. While the Hs correlation coefficient is 0.86. Comparative analysis indicates that COAWST has higher accuracy than WRF and ERA5, particularly in capturing the asymmetrical phenomena of wind and wave field. The high-value regions of the wind and wave fields are concentrated in the first quadrant around the typhoon center. The COAWST model output, combined with empirical orthogonal function (EOF) analysis and the Ekman-Stokes number, is used to quantitatively evaluate the contributions of wind and wave effects to ocean surface flow. The peak Stokes drift velocity reaches 0.73 m/s, with a maximum transport intensity of 13 m²/s and a transport depth of 20 meters. EOF analysis indicates that the first two modes explain over 88% of the Stokes transport. The first mode represents the spatial distribution of Stokes drift during the typhoon, while the second mode captures the temporal evolution of drift velocity. This study provides insight into atmosphere-ocean interactions during extreme weather conditions by using the COAWST model to analyze Stokes drift and its influence on ocean surface dynamics.

Combined effect of wind and sea excitations on the internal resonance response of floating offshore wind turbines

Abstract The sea excitation is added into a reduced nonlinear model of floating offshore wind turbine, in order to assess its effect on the system dynamics. To this aim, the sea wave motion is modelled as heave displacement of the turbine tower, which results in a parametric excitation to the along-wind displacement. The occurrence of the 1:1 internal resonance between along-wind and cross-wind oscillations is investigated by means of an asymptotic approach based on the multiple scale method. It is shown that the coupled solutions arising as a result of the wind forcing undergo a significant modification in terms of stability and quality of the response precisely because of the additional presence of the excitation due to the sea waves. A behavior chart is obtained to describe the model response as a function of the forcing parameters. The analytical results are verified by comparison with numerical simulations in terms of bifurcation diagrams and reconstructed solutions.

Computational Analysis of Wind Neighborhood Effects on Buildings: A Comparison Between Closure Models for Turbulence

Determining the neighboring effects of wind is a complex task, as generic approaches are often unable to accurately capture the interactions between buildings and their surrounding environment. For this reason, standard guidelines may be insufficient for determining these effects, making it necessary to rely on wind tunnel testing or numerical simulations through computational fluid dynamics (CFD). This study presents an analysis of the changes in aerodynamic coefficients of the CAARC (Commonwealth Advisory Aeronautical Research Council) building due to the presence of neighboring structures that interfere with wind flow. The neighborhood consists of eight blocks with proportions of 1:1:3. Turbulence was modeled using the Reynolds-Averaged Navier-Stokes (RANS) approach, employing the k-omega and k-omega SST turbulence closure models. A comparative analysis of the results obtained from these two models is presented. The study was conducted by varying the system’s orientation from 0 to 90 degrees in 15-degree intervals. Results show that the perimeter buildings create a shielding effect on the centrally located CAARC building, leading to a reduction in the drag coefficient. Additionally, for some angles, the presence of neighboring structures caused an increase in the torsional and lift coefficients.

Understanding the Influence of the Tropical Intraseasonal Oscillation in Predicting the Indian Ocean Dipole

Abstract The Indian Ocean dipole (IOD) is an important source of seasonal–interannual climate prediction. However, predicting the IOD itself is a long-standing challenge due to in part the influence of tropical intraseasonal oscillation (ISO). This study revisits the influence of the ISO on the evolution of the IOD. Furthermore, the impact of intraseasonal signals on the IOD prediction is investigated using an atmosphere–ocean coupled model. Compared to the prediction without atmospheric data initialization (nudging toward observed atmosphere), the prediction skill of the IOD at lead times of 1–6 months is improved. This improvement may benefit from a realistic initial condition and prediction in the first month for tropical ISOs such as the boreal summer intraseasonal oscillation (BSISO) and its associated easterly/westerly wind events (E/WWEs). As seen in the observation and predictions, the frequency of the active BSISO in summer is significantly correlated to the SST anomalies over the eastern Indian Ocean (EIO) in autumn, and the WWEs in summer excite downwelling Kelvin waves and accumulate heat in the subsurface of the EIO. However, the effect of atmospheric nudging varies when predicting different IOD events. For instance, it improves the prediction of a positive IOD (pIOD) in 1997, while it degrades the prediction of a pIOD in 2006, which is attributed to the asymmetrical relationship between intraseasonal easterly/westerly wind and SST in the EIO. Our results reinforce the importance of high-frequency signals in the IOD prediction. The limited skill in predicting the ISO and the across-time-scale interactions may restrict the model’s capability in predicting the IOD.

Prevent sand accumulation under the windbreak wall along railways in strong wind areas

The Lanxin High-Speed Railway is the world's first high-speed railway to pass through a strong wind region. Many windbreaks were installed along the railway line to reduce the adverse effects of wind on passing trains. The windbreak wall blocks strong wind, reduces the velocity of sand particles, and minimizes sand accumulation on the track. This paper proposes a solution based on fluid mechanics and the two-phase flow of wind and sand to reduce sand accumulation on railway tracks. Wind tunnel experiments and numerical simulations are conducted for three scenarios: the existing windbreak wall and a 45-degree inclined board installed at the wall's top or the leeward side. The results show that the sand accumulation and wind speed are higher on the windward side. The largest sand accumulation occurs when the 45-degree inclined plate is installed at the top and the wind speed is 15 m/s. The sand accumulation on the track is the lowest, the negative wind speed is the highest when the 45-degree inclined plate is located at the top on the windward side, and the wind speed is 30 m/s. Sand accumulation on the track can be minimized by taking advantage of the highly turbulent area. The sand particle size on the actual track is lower than the average sand particle size at the start of the sand bed. Our results can be used to optimize measures to prevent or minimize sand accumulation in railway lines and towns in windy areas and mitigate desertification.

Role of vacancy wind effect or cross phenomenological constants of Onsager formalism considering actual (ideal or non-ideal) molar volume variation on diffusing elements in binary solid solutions

Role of vacancy wind effect or cross phenomenological constants of Onsager formalism considering actual (ideal or non-ideal) molar volume variation on diffusing elements in binary solid solutions

Atmospheric wind effects on depressurization for indoor asbestos pollution containment: experimental analysis and a ventilation network model validation

Atmospheric wind effects on depressurization for indoor asbestos pollution containment: experimental analysis and a ventilation network model validation

Parametric Study of Internal Curing of Concrete Using Brick Chips: A Review

Abstract: As urban landscapes evolve with taller skyscrapers, the design and safety of high-rise buildings under wind forces have become critical considerations. This study explores the impact of aspect ratios—height-to-width proportions—on the wind behavior of buildings. Tall, Shorter, wider structures are less vulnerable to wind-induced vibrations than slim buildings having high aspect ratios with low aspect ratios face challenges in stability and strength. The research examines how building shape and aspect ratios influence structural behavior under wind loads. Key parameters, including maximum displacements, story drift, shear forces, and bending moments, are analyzed to assess wind effects. The study also compares buildings of varying aspect ratios but equal floor areas to determine optimal designs. By identifying the most suitable aspect ratios for high-rise structures, this research aims to enhance safety, functionality, and aesthetic appeal while addressing the challenges posed by wind forces in urban environments.

Atmospheric wind energization of ocean weather

Ocean weather comprises vortical and straining mesoscale motions, which play fundamentally different roles in the ocean circulation and climate system. Vorticity determines the movement of major ocean currents and gyres. Strain contributes to frontogenesis and the deformation of water masses, driving much of the mixing and vertical transport in the upper ocean. While recent studies have shown that interactions with the atmosphere damp the ocean’s mesoscale vortices O(100) km in size, the effect of winds on straining motions remains unexplored. Here, we derive a theory for wind work on the ocean’s vorticity and strain. Using satellite and model data, we discover that wind damps strain and vorticity at an equal rate globally, and unveil striking asymmetries based on their polarity. Subtropical winds damp oceanic cyclones and energize anticyclones outside strong current regions, while subpolar winds have the opposite effect. A similar pattern emerges for oceanic strain, where subtropical convergent flow is damped along the west-equatorward east-poleward direction and energized along the east-equatorward west-poleward direction. These findings reveal energy pathways through which the atmosphere shapes ocean weather.

Biaxial Resistance of Pre-Engineered Beam Hangers in Glulam

In timber construction, Glulam post-and-beam systems are commonly used to transfer vertical loads to the foundation. In such systems, the connections play a critical role in structural performance. Pre-engineered connectors, which facilitate fast and efficient assembly, are typically designed to resist only vertical shear loads. However, during seismic and wind events, post-and-beam systems deform horizontally, and axial forces develop at the connections. In this research, the performance of RICON and MEGANT pre-engineered connectors was studied under biaxial loading involving concurrent shear and axial forces. A total of 12 full-scale tests on Glulam frame segments were conducted. Neither type of connector experienced any resistance loss under concurrent shear loads equal to the factored shear resistance and axial loads equal to 5% of the factored shear resistance. The axial load-carrying capacity of the RICON and MEGANT connectors was up to 124% and 97% of their factored shear resistance, respectively. The global failure of all the studied connectors demonstrated both ductility and residual deformation capacity. These results provide valuable information for engineers designing Glulam post-and-beam systems in seismic regions.

Dynamic Response of Suspension Bridges Due to Coupling Between Buffeting and Aeroelastic Flutter

The effects of turbulent winds on suspension bridges are considerable, significantly influencing the bridge's floating instability and, as a result, its safety and performance. Predicting the coupled response of buffeting and flutter in suspension bridges is an advanced area of structural and aeroelastic engineering. Buffeting and flutter are not independent phenomena; buffeting, by exciting specific natural frequencies of the bridge, can contribute to the onset of flutter. Furthermore, once flutter is triggered, it alters the dynamics of the bridge, potentially amplifying the effects of buffeting. The interaction between these two phenomena can lead to complex dynamic responses that are challenging to predict through separate analyses. This paper explores this phenomenon in the time domain, requiring the expression of aerodynamic forces via convolution integrals, which incorporate the aerodynamic impulse function, structural motions, and wind fluctuations. We analyzed the aerodynamic response of the old Tacoma Bridge in the USA, situated on complex terrain and subjected to turbulent winds. A formulation that accounts for the lateral, vertical, and torsional motions of the bridge deck structure was used. The Beta-Newmark numerical algorithm was employed to integrate the bridge’s time response. Subsequently, parametric studies were conducted to further elucidate the concepts of buffeting-flutter coupling in long-span suspension bridges, aiming to assist designers in developing effective control protocols.

Not Just Winds: Why Models Find That Binary Black Hole Formation Is Metallicity-dependent, while Binary Neutron Star Formation Is Not

Abstract Both detailed and rapid population studies alike predict that binary black hole (BHBH) formation is orders of magnitude more efficient at low metallicity than high metallicity, while binary neutron star (NSNS) formation remains mostly flat with metallicity, and black hole–neutron star mergers show intermediate behavior. This finding is a key input to employ double compact objects as tracers of low-metallicity star formation, as spectral sirens, and for merger rate calculations. Yet the literature offers various (sometimes contradicting) explanations for these trends. We investigate the dominant cause for the metallicity dependence of double compact object formation. We find that the BHBH formation efficiency at low metallicity is set by initial condition distributions, and conventional simulations suggest that about one in eight interacting binary systems with sufficient mass to form black holes will lead to a merging BHBH. We further find that the significance of metallicities in double compact object formation is a question of formation channel. The stable mass transfer and chemically homogeneous evolution channels mainly diminish at high metallicities due to changes in stellar radii, while the common envelope channel is primarily impacted by the combined effects of stellar winds and mass-scaled natal kicks. Outdated giant wind prescriptions exacerbate the latter effect, suggesting that BHBH formation may be much less metallicity-dependent than previously assumed. NSNS formation efficiency remains metallicity-independent, as they form exclusively through the common envelope channel, with natal kicks that are assumed to be uncorrelated with mass. Forthcoming gravitational-wave observations will provide valuable constraints on these findings.

Accurate Tracking of Agile Trajectories for a Tail-Sitter UAV Under Wind Disturbances Environments

To achieve more robust and accurate tracking control of high maneuvering trajectories for a tail-sitter fixed-wing unmanned aerial vehicle (UAV) operating within its full envelope in outdoor environments, a novel control approach is proposed. Firstly, the study rigorously demonstrates the differential flatness property of tail-sitter fixed-wing UAV dynamics using a comprehensive aerodynamics model, which incorporates wind effects without simplification. Then, utilizing the derived flatness functions and the treatments for singularity, the study presents a complete process of the differential flatness transform. This transformation maps the desired maneuver trajectory to a state-input trajectory, facilitating control design. Leveraging an existing controller from the reference literature, trajectory tracking is implemented. Subsequently, a low-cost wind estimation method operating during all flight phases is proposed to estimate the wind effects involved in the model. The wind estimation method involves generating a virtual wind measurement utilizing a low-fidelity tail-sitter model. The virtual wind measurement is integrated with real wind data obtained from the pitot tube and processed through fusion using an extended Kalman filter. Finally, the effectiveness of our methods is confirmed through comprehensive real-world experiments conducted in outdoor settings. The results demonstrate superior robustness and accuracy in controlling challenging agile maneuvering trajectories compared to the existing method. Additionally, the test results highlight the effectiveness of our method in wind estimation.

Test results of the shore system for optimizing marine vessel traffic

The article presents the results of research a prototype of a coastal software and hardware complex, which calculate optimal routes. The purpose of the article is to analyze the quality of the calculated routes depending on the effect of meteorological conditions in the navigation area. The routes plotted using the created prototype of the coastal software complex, which use information from ships and satellites allows creating and adjusting the optimal route of the vessel in the process of seaway. The analysis carried out on base of actual voyages of ships from the port of Vladivostok to the port of Magadan and Petropavlovsk-Kamchatsky. Geographic, real and meteorological (proposed by the complex) routes were compared in article. An analysis was carried out of the effect of the speed and direction of the surface wind, the speed and direction of surface sea currents and the parameters of sea waves (wave height, direction of propagation and period) on the ship’s motion. In the article, was estimated the calculated and actual speed of the vessel. The presented coastal hardware and software complex calculated meteorological models of the selected in article ships, which point to the change in their speed and course depending on the surrounding hydrometeorological conditions and ship’s parameters. The analysis result showed the inverse dependence of the effect of surface wind and sea waves on the ships speed and the direct dependence on its draft. It is give information that the change in course significantly affects the speed, slowing down it. The complex offers route options with the required track angle, compensating for the ships drift, thereby providing more favorable traffic conditions. The proposed mathematical models allow us to estimate the approximate time of the ship’s routes along alternative routes. The article shows that the complex offers route options that allow saving about 2–3 % of the total route time, which for the routes research in the article, is 2–4 hours.

Effect of Northeast Pacific Wind on the Improvement of El Niño Prediction in a Climate Model

Abstract The role of the northeast Pacific wind in the dynamics of El Niño has been proposed in previous theoretical studies. However, the actual effect of northeast Pacific wind on improving El Niño prediction remains unclear, and the mechanisms through which northeast Pacific improves El Niño predictions are not fully understood. In this study, we investigate the role of northeast Pacific wind in improving El Niño prediction. By utilizing CESM that assimilates the northeast Pacific wind, the model improves prediction skills of ENSO indices at a lead time of 6–12 months, with a correlation three times higher than the predictions without nudged northeast Pacific wind. Nudging northeast Pacific wind in the model enhances the prediction of central Pacific (CP) El Niño, thus leading to approximately 30% increase in the hit ratio of correct prediction of El Niño. However, the model overestimates CP El Niño predictions when the nudged northeast Pacific wind is incorporated. The mechanisms for the improvement of northeast Pacific wind in El Niño predictions are investigated. In spring, El Niño development is attributed to the wind–evaporation–SST (WES) feedback and oceanic downwelling induced by subtropical westerly wind stress. In contrast, during summer, El Niño development is dominated by the summer deep convection (SDC) response. During subsequent summer–autumn, anomalous surface latent heat flux related to wind speed and net shortwave radiation associated with the low cloud–SST feedback contribute to El Niño development. These processes are more favorable for CP El Niño development. This study implies that accurately simulating air–sea coupling associated with northeast Pacific wind may be an effective approach in improving El Niño prediction.

Study on aerodynamic performance of floating offshore wind turbine with fusion winglets under yaw motion

ABSTRACT Floating offshore wind turbines (FOWTs) are subject to the effects of waves, currents, and wind, which induced the platform's six degrees of freedom motion affects the aerodynamic performance of FOWTs. The yaw motion not only changes the incidence angle of the incoming flow, but also adds an angular velocity to the blades. Numerous studies have shown that winglets can increase the blade's total aerodynamic efficiency. This paper investigates the aerodynamic performance of FOWTs with fusion winglets during yaw motion. The findings demonstrate that the effect of changing frequency on wind turbine power is more significant at high amplitude conditions, when the frequency is increased from 0.1 Hz to 0.2 Hz with the amplitude of 6°, the average power growth rate of the wind turbine with winglets is 3.91% higher than the average power growth rate of the wind turbine without winglets.

Simulations suggest offshore wind farms modify low-level jets

Abstract. Offshore wind farms are scheduled to be constructed along the East Coast of the US in the coming years. Low-level jets (LLJs) – layers of relatively fast winds at low altitudes – also occur frequently in this region. Because LLJs provide considerable wind resources, it is important to understand how LLJs might change with turbine construction. LLJs also influence moisture and pollution transport; thus, the effects of wind farms on LLJs could also affect the region’s meteorology. In the absence of observations or significant wind farm construction as yet, we compare 1 year of simulations from the Weather Research and Forecasting (WRF) model with and without wind farms incorporated, focusing on locations chosen by their proximity to future wind development areas. We develop and present an algorithm to detect LLJs at each hour of the year at each of these locations. We validate the algorithm to the extent possible by comparing LLJs identified by lidar, constrained to the lowest 200 m, to WRF simulations of these very low LLJs (vLLJs). In the NOW-WAKES simulation data set, we find offshore LLJs in this region occur about 25 % of the time, most frequently at night, in the spring and summer months, in stably stratified conditions, and when a southwesterly wind is blowing. LLJ wind speed maxima range from 10 m s−1 to over 40 m s−1. The altitude of maximum wind speed, or the jet “nose”, is typically 300 m above the surface, above the height of most profiling lidars, although several hours of vLLJs occur in each month in the data set. The diurnal cycle for vLLJs is less pronounced than for all LLJs. Wind farms erode LLJs, as LLJs occur less frequently (19 %–20 % of hours) in the wind farm simulations than in the no-wind-farm (NWF) simulation (25 % of hours). When LLJs do occur in the simulation with wind farms, their noses are higher than in the NWF simulation: the LLJ nose has a mean altitude near 300 m for the NWF jets, but that nose height moves higher in the presence of wind farms, to a mean altitude near 400 m. Rotor region (30–250 m) wind veer is reduced across almost all months of the year in the wind farm simulations, while rotor region wind shear is similar in both simulations.

Train-bridge interaction under correlated wind and rain using machine learning

The stochastic response of the high-speed train running along the bridge is susceptible to significant effects of wind and rain simultaneously. In this study, an efficient probability method for simulating the train-bridge interaction (TBI) was developed by combining wind-rain and train-bridge interaction (WRTBI) models with machine learning methods. The high-speed train was defined as multibody system (MBS) and the bridge was described over finite element method (FEM). The wind load was modeled based on the standard turbulent model and the rain load was defined according to Euler multi-phase model. The WRTBI was solved using a co-simulation method between finite element analysis and multibody system (FEA-MBS). A machine learning consisting of support vector machine (SVM) and Latin hypercube sampling (LHS) was introduced to substitute further FEA-MBS simulations, to overcome time-consuming issue. The results show that when the train runs along the bridge at the speed range of 260 km/h to 300 km/h, the maximum error is 12% in the case where the wind and rain loads are considered with the case where only the wind load is considered. The maximum displacement of the bridge in z direction increase to around 33.33%. from 25 to 100 years return period.

Intensification of sediment flux by wind-induced residual currents in a heavily contaminated, micro-tidal bay.

Wind-induced currents are the major forces responsible for sediment resuspension and transport in micro-tidal bays. To reveal the impact of wind-induced residual currents on the sediment flux, in-situ measurements using acoustic Doppler current profilers (ADCPs) were conducted at two mooring stations in a heavily contaminated, micro-tidal Onsan Bay. During the mooring period, the suspended sediments at both stations were transported seaward (landward) at the surface (bottom) layer mainly through the residual currents (mean-flow flux Fmean: > 70% of the total flux). Under northerly winds, the landward bottom residual currents at both stations strengthened, resulting in the "intensification" of landward Fmean. This suggests that the northerly winds might be a primary factor intensifying the landward sediment fluxes, potentially resulting in the increased sediment deposition into the bay. The findings provide insights into managing sedimentation in contaminated coastal bays and highlight the importance of wind effects on sediment transport in micro-tidal bays.