Reduced Wind Speed Research Articles

Aerosol forces mesoscale secondary circulations occurrence: evidence of emission reduction

Here, we present modeling evidence of the influences of aerosol feedback on secondary circulations (SCs). The results show that in heavily PM2.5 polluted Beijing-Tianjin-Hebei (BTH) areas, the aerosol feedback is the primary factor on the occurrence and development of mesoscale SCs in the atmospheric boundary layer. Modeling evidence reveal that the impact of aerosol feedback on SCs is proportional to PM2.5 concentrations or precursor emissions. During the 2014 Asia-Pacific Economic Cooperation (APEC) with extraordinary emission reduction, the time levels of SCs significantly decreases to ~37.3% of the periods without emission reduction before and after APEC period. The simulated PM2.5 during APEC are ~47.6% of before and after APEC period, and the measured concentration ratio at 47.7%. The largest variation in SC occurred during the afternoon, which should be related to the stronger solar radiation. We found that the reduction in wind speed caused by aerosol feedback and related convergence and divergence of the air mass play a pivotal role in SCs evolution. Against the background of prevailing westerly winds in BTH, the strengthening and appearance of clockwise SCs caused by aerosol feedback leads to an increase in the frequency of surface easterly U-wind. These phenomena have also been validated in two other emission reduction events and the emission reduction actions in the BTH region in January and July of 2014, 2017, and 2020, respectively. The results of this paper showing substantial impact of aerosol feedback on SCs, which could help promote our understanding of content and level of aerosol feedback to atmospheric changes.

Ecological and environmental effects of global photovoltaic power plants: A meta-analysis.

The construction of photovoltaic power plants (PVPPs) globally not only mitigates climate change but also exerts various impacts on terrestrial ecosystems. A comprehensive exploration of the intensity of PVPPs on the ecological environmental elements of terrestrial ecosystems, as well as their regulatory mechanisms, is an urgent scientific issue that must be addressed within the context of carbon balance. In this study, we conducted a meta-analysis to investigate the soil, climate, and biological effects of PVPPs construction, as well as changes in ecosystem CO2 fluxes. Our analysis synthesized data from 42 original studies encompassing over 4300 observations. Findings revealed that a significant reduction in wind speed and soil temperature within the photovoltaic field, with average changes of -63.55% (confidence intervals (CI): [-70.77, -56.32]) and -9.72%, CI [-18.51, -0.93], respectively. Concurrently, there was an average increase of 301.63%, CI [14.14, 589.13] in soil moisture content and gross primary productivity, and 28.52%, CI [14.29, 42.75], respectively. However, no significant effects were observed on other ecological environmental factors. Both the random forest model and mixed effects model highlighted key driving factors such as air temperature and humidity, location under the photovoltaic panel, monthly variations, geographical environment, and photovoltaic scale, which influenced the ecological responses to PVPPs. Furthermore, statistical cluster analysis demonstrated that the thresholds of key driving factors will significantly affect the response of ecological environment factors to PVPPs. This study enhances our comprehension of the ecological and environmental implications of PVPPs construction and offers valuable insights for policymakers aiming to implement 'photovoltaic+ecological' integrated management strategies.

Numerical investigation on vortex-induced vibration characteristics and vortex shedding mechanism of the triple-box girder

Box girders are increasingly utilized in extensive-span bridges due to their favorable aerodynamic stability and excellent traffic capacity. Nevertheless, the presence of gaps between these girders renders them highly sensitive to vortex-induced vibrations (VIV). This study utilized numerical simulation approach to explore the induced mechanism and vibration characteristics of vertical VIV of a triple-box girder with linear webs at [Formula: see text] attack angle. By using the numerical model verified with the wind tunnel data, the aerodynamic characteristics of the triple-box girder are detailed analyzed from the aspects of fundamental flow features, vortex shedding mechanism, force coefficients, vibration response and transient pressure coefficient distribution at various reduced wind speeds and vibration stages. The results indicate that the flow states and vortex structures differ significantly across different reduced wind speeds. The vortices shed from the upstream and middle box girders impact the windward side of the middle and downstream box girders in different forms, then separate and reattach, resulting in a significant pressure difference between the upper and lower surfaces of the middle and downstream box girders, thus driving the vortex-induced vibration of the triple-box girder. In the process of vortex-induced vibration, the lift force and lift contribution of the downstream box girder increase rapidly, which exceeds the increase of the upstream and middle box girder, and is the main cause of vortex-induced vibration of the triple-box girder. Control measures should be carried out for the downstream box girder to suppress vortex-induced vibration. Moreover, during the ascent of VIV, the phase between aerodynamic lift and displacement responses is closely aligned, whereas during the descent phase, the phase difference sharply increases, ultimately stabilizing at [Formula: see text].

OPTIMIZATION OF URBAN THERMAL ENVIRONMENT FOR INDONESIA COASTAL-CLIMATE URBAN AREA: A MICROCLIMATIC MODELING

Coastal urban areas, one of which is the PIK 2, Tangerang Regency, Indonesia, as the study case, have distinctive climate characteristics: changes in land and sea breezes during different seasons and high humidity and wind speed levels, which affect thermal comfort. The optimal building mass needs to be studied to achieve ideal thermal comfort conditions, which can effectively respond to climate characteristics different from those of other urban areas. This paper investigates the existing urban thermal environment and models the impact of building orientation, form, and H/W ratio simulated in ENVI-met. Based on the study findings, it has been determined that positioning a building diagonally towards the sea at a 45-degree angle effectively reduces excessive wind speeds, resulting in a favorable PMV score. Additionally, incorporating a sky bridge into the building form design provides adequate shading and contributes to achieving optimal thermal comfort in coastal-climate urban areas. Moreover, the optimal H/W ratio is 0.5, which can reduce wind speed without significantly lowering the temperature, thereby maintaining thermal comfort.

The role of typical low vertical lattice sand barriers in regulating the airflow field on wind-eroded surfaces of photovoltaic power plants

Deserts are ideal places to build photovoltaic (PV) power plants, but this plants often face challenges from strong wind and sand activities during the operation and maintenance period, exploring the effects of PV power plant construction on wind disturbances and the control of wind and sand activities by different sand fixation measures is necessary. This study investigated the wind speed outside the PV plant, inside the plant without sand barriers measures (CK), and under three different sand-protecting barriers (gauze sand barriers (GZ), polylactic acid sand barriers (PLA), and grass grid sand barriers (GG)) inside the plant. Though calculated the surface roughness, friction velocity, wind protection effectiveness, and wind turbulence to determined the effectiveness of the barriers by these indexes comprehensively. The results show that: (1) The construction of desert PV power plant can effectively reduce the wind speed. Compared with CK, all three mechanical sand barriers within the plant reduced wind speed. Especially when the height less than 50cm, the GZ sand barriers reduced the wind speeds the most, with an average reduction rate of 101.5%. (2) All three sand barriers increased soil roughness and friction velocity within the power station. (3) At heights below 50cm, the GZ and GG sand barriers have better wind protection effectiveness than PLA sand barriers, while at hights above 100cm, the wind protection effect of PLA and GG sand barriers became less significant or even negligible (4) The wind disturbance caused by the three sand fixation measures increased with wind speed, the comprehensive performance of GZ and PLA sand barriers was superior than that of GG sand barriers and CK.

Street Canyon Vegetation—Impact on the Dispersion of Air Pollutant Emissions from Road Traffic

Roadside vegetation helps to retain air pollutants emitted by road traffic. On the other hand, its presence makes it difficult to ventilate street canyons. The paper examines the influence of vegetation on the dispersion of air pollution generated by road traffic, using the example of two street canyons—both-sided and one-sided street canyons. The study was conducted taking into account the actual emission conditions occurring on the analyzed road sections estimated using the HBEFA methodology. Subsequently, a three-dimensional pollution dispersion model named MISKAM was employed to simulate the air pollutant dispersion conditions in the analyzed street canyons. The modelling results were compared with the measurement data from air quality monitoring stations located in these canyons. The obtained results indicated that the presence of vegetation can significantly impact on the air dispersion of traffic-related exhaust and non-exhaust emissions. The impact of vegetation is more pronounced in the case of a street canyon with dense, high-rise development on both sides than in the case of a street canyon with such development on only one side. The results for the both-sided street canyon demonstrate that the discrepancy between the scenario devoid of vegetation and the scenario with vegetation was approximately 5 µg/m3 (10%) for PM10 and approximately 54 µg/m3 (45%) for NOx, with the former scenario showing lower values than the latter. Nevertheless, the scenario with the vegetation exhibited a lesser discrepancy with the air quality measurements. Vegetation functions as a natural barrier, reducing wind speed in the street canyon, which in turn limits the spread of pollutants in the air, leading to pollutant accumulation near the building walls that form the canyon. Consequently, atmospheric dispersion modelling must consider the presence of vegetation to accurately evaluate the effects of road traffic emissions on air quality in urban areas, particularly in street canyons. The results of this study may hold importance for urban planning and decision-making regarding environmental management in cities aimed at improving air quality and public health.

Land coverage prediction using convolutional neural network for enhanced wind loading estimation

PurposeThe wind loading on a building is likely to deviate further from the known wind loading due to the complexity of the real-world land coverage. To address this issue, research is needed in two separate areas. First, wind tunnel testing needs to be conducted for more complex terrains. Second, research is needed to classify real-world land coverage with high accuracy, specifically for wind engineering applications. This paper deals with this second area of research. The machine learning-based land cover prediction is a promising technique because it can remove subjectivity in human interpretation of upwind terrain.Design/methodology/approachThis paper presents a new deep neural network for land coverage prediction that can distinguish low- and mid-rise buildings in the built environment to enhance the estimation of surface roughness necessary in wind engineering. For the dataset, Landsat 8 satellite images were used. A patch-based convolutional neural network was employed and improved. The network predicted the land coverage at the center of the patch. Two different label schemes were used where the proposed network either achieved better accuracy than the conventional model or recognized additional building types while maintaining a similar level of accuracy.FindingsCompared to the validation accuracy of 78% in a previous study, the proposed method achieved the validation accuracy of 90% thanks to the improvements made in this study as well as the consolidation of labels with similar surface roughness. When additional building categories were added, the validation decreased to 80%, which is comparable to the previous study but is now able to predict different building types.Originality/valueThe improvement of the proposed method will depend on the site characteristics. For the sites tested in this paper, the error reduction in wind speed and pressure was up to about 55%. In addition to more accurate wind speed and pressure, better identification of buildings will benefit wind engineering research, as different building types cause different downwind effects. An example application would be automated recognition of areas that have a certain distance from the target building type to identify downwind areas affected by high winds.

Greening the arid: the impact of urban vegetation on the outdoor thermal comfort in hot and dry city

This article examines the impact of urban vegetation on outdoor thermal comfort in the hot and dry city of Biskra, Algeria. The study employs the ENVI-met model to simulate various vegetation arrangement scenarios and evaluate their effectiveness in improving microclimate parameters and thermal comfort. The results show that the scenario with the densest and most extensive vegetation cover (90% of the sample area) provided the greatest reduction in air temperature, mean radiant temperature, and duration of severe thermal stress, compared to the baseline scenario with minimal vegetation. However, even the best-performing scenario did not achieve a thermally comfortable outdoor environment, likely due to the heat-absorbing properties of the asphalt ground and the reduced wind speeds caused by the dense vegetation. The study highlights the importance of considering vegetation type, cover density, and strategic placement in urban planning to mitigate the harsh climatic conditions in hot and dry cities like Biskra.

Enhanced wind energy harvesting through omnidirectional airflow metamaterial concentrators

Wind energy generation is constrained by low density and intermittency. To address these challenges, this study proposes an omnidirectional airflow metamaterial concentrator lens that utilizes a novel complex gradient structure inspired by metamaterial principles. The study's framework includes the design, simulation, and performance evaluation of the concentration lens under varying wind conditions. The lens amplifies the local flow energy density by up to 360% compared to the impinging influx. Numerical simulation analysis elucidates the underlying operational mechanism, demonstrating a significant reduction in the startup wind speed and increased energy capture efficiency. Results indicate that concentrator lens can enhance wind energy exploitation by improving the efficiency of energy capture and providing a viable solution to mitigate the limitations of current wind energy technologies.

TerraWind: A Deep Learning‐Based Near‐Surface Winds Downscaling Model for Complex Terrain Region

AbstractWind downscaling is crucial for refining coarse‐scale wind estimates, improving local‐scale predictions, and supporting various applications like risk assessment and planning. Dynamic downscaling models demand extensive computational resources and time, leading to a shift toward more efficient statistical downscaling, whereas it often overlooks inter‐variable and inter‐station spatial correlations. Addressing this, we propose TerraWind, a deep learning‐based downscaling method for complex terrain regions. TerraWind enhances accuracy by incorporating topographic factors and inter‐station linkages, capturing wind field interactions with terrain at multiple scales. Experimental results in Eastern China demonstrate that TerraWind reduces wind speed Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) by an average of 42.6 and 33.3, respectively, compared to three interpolation methods (bicubic, bilinear, and Inverse Distance Weighting). Furthermore, TerraWind achieves an average reduction of 35.3 in wind speed MAE and 25.6 in wind speed RMSE compared to four deep learning models (Wind‐Topo, DeepCAMS, RCM‐emulator, and Uformer).

Extrapolation is not enough: impacts of extreme land use change on wind profiles and wind energy according to regional climate models

Abstract. Humans change climate in many ways. In addition to greenhouse gases, climate models must therefore incorporate a range of other forcings, such as land use change. While studies typically investigate the joint effects of all forcings, here we isolate the impact of afforestation and deforestation on winds in the lowermost 350 m of the atmosphere to assess the relevance of land use change for large-scale wind energy assessments. We use vertically resolved sub-daily output from two regional climate models instead of extrapolating near-surface winds with simplified profiles. Comparing two extreme scenarios, we report that afforestation reduces wind speeds by more than 1 m s−1 in many locations across Europe, even 300 m above ground, underscoring its relevance at hub heights of current and future wind turbines. We show that standard extrapolation with modified parameters approximates long-term means well but fails to capture essential spatio-temporal details, such as changes in the daily cycle, and it is thus insufficient to estimate wind energy potentials. Using adjacent climate model levels to account for spatio-temporal wind profile complexity, we report that wind energy capacity factors are strongly impacted by afforestation and deforestation: they differ by more than 0.1 in absolute terms and up to 50 % in relative terms. Our results confirm earlier studies showing that land use change impacts on wind energy can be severe and that they are generally misrepresented with common extrapolation techniques.

Intensification of an Autumn Tropical Cyclone by Offshore Wind Farms in the Northern South China Sea

AbstractThe rapid development of the wind industry is accompanied by increasing environmental impacts. Currently, there is a lack of research on the impacts of offshore wind farm (OWF) on tropical cyclone (TC) intensity, including the mechanisms involved. This research is carried out by using a coupled and an uncoupled numerical model to investigate the impact of OWF on an autumn TC in the northeastern South China Sea. The results show that the wind speed deficit caused by OWF leads to an increase in surface pressure on the inflow side. This causes the surface pressure in the TC periphery to increase by advection, even if the TC is some distance away from the OWF. The increase in pressure gradient from the periphery to the TC center enhances the TC secondary circulation, thereby intensifying the TC. When the TC enters the OWF, the above mechanisms weaken and the ocean dominates the TC intensification. This is because the reduction in wind speed caused by the OWF results in a weaker sea surface current velocity, which weakens the flow of upstream cold water into the OWF, warming the sea surface temperature (SST) within the OWF. This implies that the horizontal gradient of the local SST is an important factor to be considered in the development of OWF. Sensitivity experiments indicate that OWF can also intensify other types of TC, and that higher cut‐out wind speeds lead to stronger intensification effects. These results also provide a new perspective on TC intensity forecasts.

Comparison of windblown sand environmental effects between railway embankment and bridge and its engineering significance

The embankment and bridge are the basic forms of railway lines. To date, no reports have addressed the optimal form to adopt when passing through sandy areas. Therefore, models of railway embankment and bridge were created, and wind tunnel experiments were conducted to compare the differences in wind speed, flow field, sand transport rate, and other wind–sand environmental effects of railway embankment and bridge. Results show that wind speed reduction areas in the upwind and downwind directions were observed for the railway embankment and bridge. In these areas, the extent and degree of wind speed reduction on the embankment were greater than those on the bridge. At the top of the embankment, especially on the windward slope shoulder, an obvious area of wind speed increase was observed. Similarly, a distinct area of wind speed increase was found between the top of the windward side slope shoulder and 3H downwind of the bridge. Within these regions, the range of wind speed increase on the embankment was smaller than that on the bridge, but the degree of increase was greater than that on the bridge. The range of variation in wind speed on the embankment was generally greater than that on the bridge. The wind–sand flow field around the embankment exhibited greater variability than that around the bridge. Moreover, higher wind–sand flow passage rates on the embankment than on the bridge. This study aims to offer recommendations to assist in the route selection, surveying, and design of railways in sandy regions.

Persistent trends and geographic traits of heat waves in a changing climate

Abstract By adopting a heatwave (HW) definition with a ∼4-year recurrence frequency at world hot spots, we first examined the 1940–2022 HW climatology and trends in lifespan (duration), severity and recurrence frequency, by comparing the first and last 20-year periods of this 83- year record. Generally, HWs are becoming more frequent and more severe in the extra-tropic and mid-latitude regions. Increased HWs are not temporally uniform and tend to cluster together, posing a one-two punch for ecosystems. North America, regions affected by HWs in the early 21st Century expanded by ∼47% relative to those in the mid-20th Century, contributed primarily by regions starting to be exposed to HWs in the early 21st Century. Mid-latitude basins are vulnerable areas. Geographic shifts can be attributed to adjustments in planetary wavelengths due to increased air viscosity (related to global warming). Polar amplified warming, leading to a reduced equator to pole temperature gradients and an overall reduction in zonal wind speeds across midlatitudes, promotes amplified planetary wave amplitudes, leading to more severe and persistent blockings and cutoffs, thus an increase in HW frequency, severity, and duration. Climate model simulations under a business-as-usual emission scenario corroborate trends in HW severity and lifespan increases, supported by a strong intermodal consensus. HW periods correspond to heightened planetary boundary layer (PBL) depths, which increase with eddy viscosity. The temperature-dependent nature of air viscosity underscores the similarity between trends in PBL depth and HW areal extent in a warming climate.

Long-term changes in black carbon aerosols and their health effects in rural India during the past two decades (2000–2019)

Black carbon (BC) is a short-lived atmospheric aerosol having light absorbing properties with climate-changing potential. In addition, BC aerosols are also responsible for several adverse health effects including cardiovascular and respiratory problems. Here, we examine the long-term changes in BC, using MERRA-2 (Modern-Era Retrospective analysis for Research and Applications) and Emissions Database for Global Atmospheric Research (EDGAR) data for the period 2000–2019, and the associated health burden in rural India. This study finds a decreasing trend in BC in the rural IGP (Indo-Gangetic Plain) and NWI (North West India) during 2007–2019, at about -0.004 and –0.005 μg/m3/yr, respectively. A significant reduction in BC (from 0.03 to 0.01 μg/m3/yr after 2006) is observed in the rural Peninsular India (PI), where the reduced wind speed limits the transport of BC aerosols from other regions and thus, limits the BC concentration there. Our assessment finds that government policies such as BS (Bharat Stage) emission norms, electrification of rail routes, use of electric and compressed natural gas-based vehicles, the transformation of brick kilns to zig-zag technology, mechanised farming for on-site handling of crop residues and recent changes in atmospheric drivers (e.g. winds in IGP) contributed to this reduction in BC. However, the health burden associated with BC causes the highest all-cause mortality to be around 5,17,651 and 34,082 inhabitants in winter (December-February) and post-monsoon (October-November) seasons, respectively, in the rural IGP in the latest year 2019. In brief, the reduction of BC in rural India indicates that it complements the government policies. However, an improvement in the policy implementation might prove to be conducive to reduce the BC-driven mortality and regional climate warming.

Synergistic windbreak efficiency of desert vegetation and oasis shelter forests.

This study investigates the novel approach of synergizing desert vegetation with shelter forests to enhance windbreak efficiency in a transitional zone between the Korla oasis and the Taklimakan Desert, northwest China. Through an extensive field survey and experimental setup, we evaluated the impact of different shelterbelt configurations on wind speed reduction. Three types of shelter forests were examined: multi-row Poplar (Populus alba), single-row Jujube (Ziziphus jujube), and a mixed-species layout combining one row of Jujube and two rows of Poplar trees. Wind speed measurements were recorded at multiple heights across three zones-open field, between desert vegetation and shelterbelt, and leeward of the shelterbelt-over a three-month period (April to June, 2023). The findings reveal a significant reduction in wind speed, particularly on the leeward side, with multi-row and mixed-species configurations proving the most effective. The highest synergistic efficiency, observed in the mixed-species shelter forest, showed a windbreak efficiency improvement of over 20% compared to desert vegetation alone. This study provides new insights into the combined effectiveness of desert vegetation and shelter forests, offering a strategic framework for designing shelterbelts in arid environments. These results underscore the critical role of diverse, structured vegetation arrangements in combating wind erosion and contribute to the development of sustainable ecological management practices for desert regions worldwide.

The meteorological drivers of mass coral bleaching on the central Great Barrier Reef during the 2022 La Niña

The frequencies of marine heatwaves and thermal coral bleaching events (CBEs) over the Great Barrier Reef (GBR) continue to increase with five mass CBEs reported since 2016. While changes in the local meteorology, such as reduced wind speeds and decreased cloud cover, are known to heat the shallow reef waters, little consideration has been given to the overriding synoptic meteorology. The 2022 CBE, occurring under La Niña conditions, saw ocean temperatures at Davies Reef increase 1.9 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ \\hbox {C}$$\\end{document} over 19-days and subsequently cool 2.1 ∘C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\circ \\hbox {C}$$\\end{document} back to seasonal norms over eight days. This event was found to be triggered by repeated Rossby wave breaking disrupting the local trade winds, thus inhibiting the latent heat flux. Latent heat fluxes, the primary driver of the event, tripled as the trade winds returned via rapid coastal ridging. These same synoptic features are concurrent with the historic Lismore flooding located hundreds of kilometres south of the GBR.

A Wind Tunnel Test for the Effect of Seed Tree Arrangement on Wake Wind Speed

Changes in canopy structures caused by harvesting and regeneration practices can significantly alter the wind environment. Therefore, it is essential to understand the wind patterns influenced by seed tree arrangements for predicting seed dispersal by winds and ensuring the success of natural regeneration. This study aimed to identify how wind speed responds to seed tree arrangement designs with differing horizontal distances, vertical positions, and free-stream wind speeds. A wind tunnel test was conducted using pine saplings for a scale model of various seed tree arrangements, and the change in wake speed was tracked. The wake’s relative wind speed averaged 71%, ranging from 3.5% to 108.5%, depending on the seed tree arrangement, distance from saplings, and vertical position. It peaked within the patch of three seed trees compared to other arrangements and at the top canopy layer. The empirical function effectively described the wind speed reduction and recovery with distance from saplings. For instance, the minimum wind speed was reached at 0.6–2.2 times the canopy height, and a wind speed reduction of over 20% of the free-stream wind speed was maintained at a 1.6–7.6 canopy height. A negative relationship between the seed tree leaf area and the relative wind speed was observed only at the top canopy layer. This study presents empirical evidence on the patterns of wake winds induced by different types of heterogeneous canopy structures.

Windbreak Effectiveness of Single and Double-Arranged Shelterbelts: A Parametric Study Using Large Eddy Simulation

Shelterbelts provide essential protection against wind erosion and soil degradation, as well as protection for fruit-bearing plants and crops from strong winds. Enhancing their sheltering capabilities requires optimizing their pattern and orientation, as well as defining their height and desired canopy shape, according to the desired performance. In this work, Large Eddy Simulation is employed to investigate the flow field and windbreak effectiveness of single and double-arranged shelterbelts characterized by different geometry and resistance to the air passage for neutral atmospheric condition. In particular, the canopy of the shelterbelts is modeled as an isotropic porous medium immersed in atmospheric boundary layer flow using the Darcy–Forchheimer model. Results show that a shelterbelt with a rectangular-shaped cross-section and a large canopy height results in the most significant reduction in mean wind speed and TKE, thus providing a large wind-protection region. As the spacing distance of double-arranged shelterbelts increases, the protection zones formed by both shelterbelts are reduced. The systematic comparisons of flow patterns, drag force coefficients, and windbreak effectiveness indicators of a series of single and double-arranged shelterbelts are essential for optimizing the design and management of shelterbelts.

Scenario-based stochastic optimization on the variability of solar and wind for component sizing of integrated energy systems

The inherent intermittency and variability of renewable energy sources present significant challenges to the optimal design and implementation of integrated energy systems (IES). This paper introduces a novel stochastic optimization model that integrates advanced scenario generation and clustering algorithm for renewable energy sources within a multi-objective, bi-level optimization framework. Specifically, the clearness index is employed to represent the stochastic distribution of solar radiation intensity by beta distribution, while wind speed uncertainty is modeled seasonally using the Weibull distribution. Monte Carlo sampling with synchronous back substitution is applied for scenario generation and reduction of solar radiation and wind speed. To address the multi-objective evaluation, the analytic hierarchy process is utilized, and the joint optimization is achieved by combining a region contraction algorithm with stochastic programming. The proposed methodology is validated on an IES featuring various heating devices, incorporating uncertainties in both wind and solar energy. The results indicate that the absorption heat pump-based scheme achieves superior energy-saving performance, achieving an energy rate of 0.4724. Additionally, the compression heat pump-based scheme exhibits excellent economic efficiency and environmental sustainability, with a cost of energy of 0.3639 and a renewable fraction of 0.5536.