Wind Movement Research Articles

Sail pressures from full-scale, wind-tunnel and numerical investigations

The main results of a two-year project aimed at comparing full-scale tests, wind tunnel tests, and numerical analysis predictions are presented. Pressure measurements were obtained from both full-scale tests and wind tunnel tests, in upwind and downwind conditions. The upwind wind tunnel test condition was modelled using a Vortex Lattice code, while the downwind wind tunnel test was modelled using a Navier–Stokes code. The pressures obtained from the three different methods are compared on three horizontal sections of the headsail, mainsail and asymmetric spinnaker. In general the pressure from the three experiments showed good agreement. In particular, very good agreement was obtained between the numerical computations and the wind tunnel test results. Conversely, the results from the downwind full-scale pressure measurements showed less similarity due to a slightly tightened trim being used for the spinnaker in the on-water tests. Full-scale tests allow the action of unsteadiness due to the wind, wave and yacht movements to affect the results. This unstable environment caused the asymmetric spinnaker to move around, and a tightened trim was required to prevent the spinnaker from collapsing.

Application of Vortex Process to Cleaner Energy Generation

The vortex process generated Mechanical energy; this is produced when heat is carried upward by convection in the atmosphere. Processes for controlling and concentrating where the mechanical energy is produced could be a method of harnessing solar energy and the wind movement, but this process it’s more efficient that Wind turbines that these can only produce electricity when the speed of the oncoming wind is within certain limits. The vortex process is compared with the solar chimney phenomenon which shares the same thermodynamic basis. The physical tube of the solar chimney is replaced with a vortex and the atmospheric boundary layer acts as the solar collector. The reasons for this paper its give another option in generation of cleaner energy and also innovating power generation industry. This template explains and demonstrates how to prepare your camera-ready paper for Trans Tech Publications. The best is to read these instructions and follow the outline of this text.

The UTCI-clothing model

The Universal Thermal Climate Index (UTCI) was conceived as a thermal index covering the whole climate range from heat to cold. This would be impossible without considering clothing as the interface between the person (here, the physiological model of thermoregulation) and the environment. It was decided to develop a clothing model for this application in which the following three factors were considered: (1) typical dressing behaviour in different temperatures, as observed in the field, resulting in a model of the distribution of clothing over the different body segments in relation to the ambient temperature, (2) the changes in clothing insulation and vapour resistance caused by wind and body movement, and (3) the change in wind speed in relation to the height above ground. The outcome was a clothing model that defines in detail the effective clothing insulation and vapour resistance for each of the thermo-physiological model's body segments over a wide range of climatic conditions. This paper details this model's conception and documents its definitions.

Experimental investigation of the impact of airborne dust deposition on the performance of solar photovoltaic (PV) modules

Abstract Deposition of airborne dust on outdoor photovoltaic (PV) modules may decrease the transmittance of solar cell glazing and cause a significant degradation of solar conversion efficiency of PV modules. Previous studies of this issue indicated that dust deposition is closely related to the tilt angle of solar collector, exposure period, site climate conditions, wind movement and dust properties. However, few studies considered the influence of the properties of PV module itself on dust deposition and efficiency degradation, such as the cell types and surface materials. This experimental work aimed to study the dust accumulation onto different types of solar PV modules and the corresponding efficiency degradation. The experiment was designed and conducted in the laboratory with a sun simulator and a test chamber. The degradation of PV module efficiency caused by dust deposition under various conditions was investigated. The results indicated that dust pollution has a significant impact on PV module output. With dust deposition density increasing from 0 to 22 g m −2 , the corresponding reduction of PV output efficiency grew from 0 to 26%. The reduction of efficiency has a linear relationship with the dust deposition density, and the difference caused by cell types was not obvious. When the dust deposition density was fixed, the reductions of output efficiency at relatively lower or higher solar densities were much more severe. Moreover, the surface material may influence dust deposition and accumulation considerably. The poly-crystalline silicon module packaged with epoxy degraded faster than other modules with glass surface under the same dust concentration.

Plant resistance to mechanical stress: evidence of an avoidance–tolerance trade‐off

External mechanical forces resulting from the pressure exerted by wind or water movement are a major stress factor for plants and may cause regular disturbances in many ecosystems. A plant's ability to resist these forces relies either on minimizing the forces encountered by the plant (avoidance strategy), or on maximizing its resistance to breakage (tolerance strategy). We investigated plant resistance strategies using aquatic vegetation as a model, and examined whether avoidance and tolerance are negatively correlated. We tested the avoidance-tolerance correlation across 28 species using a phylogenetically corrected analysis, after construction of a molecular phylogeny for the species considered. Different species demonstrated contrasting avoidance and tolerance and we demonstrated a significant negative relationship between the two strategies, which suggests an avoidance-tolerance trade-off. Negative relationships may result from costs that each strategy incurs or from constraints imposed by physical laws on plant tissues. The existence of such a trade-off has important ecological and evolutionary consequences. It would lead to constraints on the evolution and variation of both strategies, possibly limiting their evolution and may constrain many morphological, anatomical and architectural traits that underlie avoidance and tolerance.

Field analog studies of the distribution of windblown sediments at Amboy Crater, California, with application to Mars

Many shallow craters in the Spirit Mars Exploration Rover site contain asymmetric distributions of windblown sediments, which could indicate the predominant local wind direction at the time of their deposition or redistribution. Terrestrial analog field work at the Amboy lava field, Mojave Desert, California, included real-time wind measurements and assessments of active sediment deposition in four small (<100m) craters. Preliminary results indicate that reverse flow or stagnant wind flow likely occurs in craters with depth-to-diameter (d/D) ratios of ≥0.05. Measurements taken within a crater of d/D of ∼0.02 do not indicate reverse flow; therefore, reverse flow is expected to cease within a d/D ranging from 0.02 to 0.05, resulting in wind movement directly over the crater floor in the downwind direction. Craters with asymmetric eolian deposits near the Mars Spirit landing site have d/D from 0.034 to 0.076, suggesting that reverse flow occurs in these craters. Thus, the position of windblown sediments in the small craters on the northwest part of the floor would indicate prevailing winds from the northwest to the southeast at the time of deposition or redistribution.

Turbary Restoration Meets Variable Success: Does Landscape Structure Force Colonization Success of Wetland Plants?

Peat ponds have been restored widely in the Netherlands to enhance the available habitat for species‐rich plant communities that characterize the early succession stages toward land. Colonization success of 33 target aquatic species has been quantified in eight complexes of new ponds. It has been related to the lay‐out of these ponds, the structure of the surrounding landscape, (historic) prevalence of source populations within the complex and within a perimeter of 10 km, and pond water quality. Colonization success was variable: between 6 and 26 target species had reached the complexes in 1998. This success was coupled to the first principal component (PC) in a principal component analysis (PCA) explaining 44% of the variation in 27 variables. This first PC correlated with historical perimeter and local within‐complex species richness, the number of ponds in the complex, the SW orientation of ditches in these complexes and pH, and transparency of the water. Age of the ponds (1–9 years), area of open water (8–42%), and shoreline density (13–43 km/km2 in the complex) did not contribute significantly to colonization success. Separation of the effect of a species‐rich surrounding landscape, the possibility to disperse through that landscape, the spatial lay‐out of the complex and transparency of the water were precluded by the strong covariance along the first PC. Probably all three are independently important. It is speculated that diel migration by waterfowl may be responsible for the dispersal of plant propagules to the pond complex, whereas within‐complex dispersal to establishment sites is enhanced by wind and water movement.

Diffusion Spreading of the Emitted Metallurgical Gas

The main parameter which shows the space distribution of the emitted gas components is the rate of concentration decrease by the increase of the distance from the point where the emitted gas appears in the atmosphere. It is considered three different driving forces leading to the spreading of the emitted gas components from the centre of the metallurgical region to its periphery:  diffusion factor – the appearance of the emitted substance is the reason of the local concentration increase, it correlates with the diffusion process;  wind load factor – the wind movement acts always in advantage direction, wind force is not space homogeneous as the diffusion force is;  chemical factor – the intensity of chemical interaction of emitted components with the atmospheric ones influences the space distribution of the interaction products (secondary emissions). The proposed method allows to predict the space-time distribution of the emitted metallurgical gas by various external conditions.

Proposed Modification to the Inhalable Aerosol Convention Applicable to Realistic Workplace Wind Speeds

The current convention for sampling inhalable aerosols was based on several mannequin studies performed in wind tunnels at wind speeds between 0.5 and 4 m s(-1). In reality, as we now know, the wind speed in most modern indoor working environments is generally at or below ∼0.2 m s(-1). Inhalability studies performed in calm air aerosol chambers have shown that human aspiration efficiency at essentially zero wind speed is not consistent with the existing inhalable aerosol convention, calling into question the universal applicability of the current standard. More recently, experiments were carried out in a new hybrid wind tunnel-calm air chamber at more representative workplace wind speeds, between ∼0.1 and 0.5 m s(-1), to fill in this knowledge gap. Comparing these new data to both the existing inhalable aerosol convention and a recently proposed alternative for low wind movement suggests that, while the existing inhalable aerosol convention remains appropriate for wind speeds above ∼0.2 m s(-1), the modified version is more appropriate for the range below ∼0.2 m s(-1).

Compensating Background for Noise due to Camera Vibration in Uncalibrated-Camera-Based Vehicle Speed Measurement System

Vision-based vehicle speed measurement (VSM) is one of the most convenient methods available in intelligent transportation systems. Existing methods use an uncalibrated camera to measure vehicle speed, but they do not consider the possibility of camera vibration that leads to poor measurement results. This paper considers the issue when the camera is tilted downward and mounted at a fixed location on a bridge crossing the target street. The camera may vibrate due to wind or bridge movement. A vision-based speed measurement system is described in this paper, along with the vertical-and-horizontal-histogram-based method, which is used to compensate the background of an incoming image. This novel method is utilized to eliminate noise coming from the displacement between an incoming image and a background image that is caused by camera vibration over time. Moreover, a method is presented to automatically detect the vanishing point based on the Hough transform and quadtree. Experimental comparisons of the system to those of the vehicle's own speedometer show that the proposed approach yields a satisfactory estimate of vehicle speed.

Air pollution in a tropical city: the relationship between wind direction and lichen bio-indicators in San José, Costa Rica

Lichens are good bio-indicators of air pollution, but in most tropical countries there are few studies on the subject; however, in the city of San José, Costa Rica, the relationship between air pollution and lichens has been studied for decades. In this article we evaluate the hypothesis that air pollution is lower where the wind enters the urban area (Northeast) and higher where it exits San José (Southwest). We identified the urban parks with a minimum area of approximately 5,000 m2 and randomly selected a sample of 40 parks located along the passage of wind through the city. To measure lichen coverage, we applied a previously validated 10 x 20 cm template with 50 random points to five trees per park (1.5m above ground, to the side with most lichens). Our results (years 2008 and 2009) fully agree with the generally accepted view that lichens reflect air pollution carried by circulating air masses. The practical implication is that the air enters the city relatively clean by the semi-rural and economically middle class area of Coronado, and leaves through the developed neighborhoods of Escazú and Santa Ana with a significant amount of pollutants. In the dry season, the live lichen coverage of this tropical city was lower than in the May to December rainy season, a pattern that contrasts with temperate habitats; but regardless of the season, pollution follows the pattern of wind movement through the city.

Ambient Air Levels and Trends of Polychlorinated Biphenyls at Four Different Sites

In this study, samples were collected in order to determine atmospheric levels of polychlorinated biphenyls (PCBs) in four different sites by using a high-volume air sampler (HVAS). Eighty-three congeners of gas and particle- phase PCBs were investigated in air samples. The total (gas+particle) concentrations for Mudanya (coastal), Butal (traffic/urban), the Uludag University Campus (semirural), and Yavuz Selim (residential) were determined as 570, 394, 412, and 316pg/m(3), respectively. These levels coincide with the values reported for the sites having similar characteristics. In terms of homolog groups, 3-chlorinated biphenyls (3-CBs) and 4-CBs constituted at least 47% of the total PCB concentration. PCBs in all sites were determined mostly in the gas phase, with a percentage from 85 to 95%. Obtained atmospheric PCB data were correlated with meteorological parameters and a significant relationship was obtained between coastal and semirural sites (p<0.05). With the movements of air transportation and wind rose possible data sources of PCBs were enlightened. Partitioning of gas/particle was examined with available models; significant relationships were determined for coastal and semirural sites especially.

A Societal Knowledge Management System: Harnessing Indigenous Wisdom to Build Sustainable Predictors for Adaptation to Climate Change

As the climate changes globally time-honoured climate in a region may change and shift to another region. Consequently, local predictors of climate may no longer apply to the area where they were born, but may be invaluable in new regions where previously reliable predictors have become outmoded This paper is set on the proposition thaI traditional (indigenous) know/edge can be a strategic source in adapting to climate change, in these changing times. The research reported in this paper takes the Societal Knowledge Management approach where knowledge that rests within local communities, is harnessed to inform local communities and scientists regarding climate change impacts, so as to adapt to them accurately. A phased study was conducted that aimed at acquiring, synthesising and disseminating traditional knowledge regarding change in monsoon patterns in India. Traditional wisdom prevalent among fhe myriad communities of India, was collected, collated and classified into knowledge spheres such as Bio-Indicators, Wind Movement, Atmospheric Pal/ems, Astrological Methods, Festivals and Rituals, Direction, Characteristics of the Rain, Characteristics of Celestial Bodies etc and incorporaled into a knowledge portal, which is the basis for building the Societal Knowledge Management System (SKM). Subsequently, the SKM is to be harmonised with scientific predictors on seasonal weather patterns will allow researchers to identify if the existing indicators and monsoon pattems are subject to change, and if so how. Research in progress is aimed at integrating the knowledge with modern science and disseminating this knowledge through local knowledge centres, at village levels. Furthermore, this study is to be replicated in Australia, by harnessing indigenous knowledge, to build the SKM for Australia that could assist in building a better understanding of the factors that impact the environment, methods of building sustainable predictors for climate and approaches for adapting the climate changes. The research reported is expected to inform policy makers, scientists, governance institutions as well as researchers regarding the applicability of indigenous knowledge in building sustainable predictors for adaptation to climate change in the two countries cited and can be extended into other countries.

Leonardo's Insects

drawings, is his written Treatise on Painting, of which an edition was published in Paris in 1651 (McCurdy 1939). However, it is his drawings that demonstrate exquisite visual problem solving—whether it applied to preliminary preparations for painting and sculpture, observations of nature, or sketches for planned inventions. These countless sketches include many subjects: the observation of the movements of water and wind, weaponry concepts, physics, botany, music, irrigation systems, architecture, studies for portraits and sculptures, details of human anatomical dissections, a plan for an underwater diving system, optics, mathematics, astronomy, observations of animals in movement, landscapes, and insects (da Vinci

The ‘Hothaps’ programme for assessing climate change impacts on occupational health and productivity: an invitation to carry out field studies

The “high occupational temperature health and productivity suppression” programme (Hothaps) is a multi-centre health research and prevention programme aimed at quantifying the extent to which working people are affected by, or adapt to, heat exposure while working, and how global heating during climate change may increase such effects. The programme will produce essential new evidence for local, national and global assessment of negative impacts of climate change that have largely been overlooked. It will also identify and evaluate preventive interventions in different social and economic settings.Hothaps includes studies in any part of the world where hourly heat exposure exceeds physiological stress limits that may affect workers. This usually happens at temperatures above 25°C, depending on humidity, wind movement and heat radiation. Working people in low and middle-income tropical countries are particularly vulnerable, because many of them are involved in heavy physical work, either outdoors in strong sunlight or indoors without effective cooling. If high work intensity is maintained in workplaces with high heat exposure, serious health effects can occur, including heat stroke and death.Depending on the type of occupation, the required work intensity, and the level of heat stress, working people have to slow down their work in order to reduce internal body heat production and the risk of heat stroke. Thus, unless preventive interventions are used to reduce the heat stress on workers, their individual health and productivity will be affected and economic output per work hour will be reduced. Heat also influences other daily physical activities, unrelated to work, in all age groups. Poorer people without access to household or workplace cooling devices are most likely to be affected.The Hothaps programme includes a pilot study, heat monitoring of selected workplaces, qualitative studies of perceived heat impacts and preventative interventions, quantitative studies of impacts on health and productivity, and assessments of local impacts of climate change taking into account different applications of preventative interventions.Fundraising for the global programme is in progress and has enabled local field studies to start in 2009. Local funding support is also of great value and is being sought by several interested scientific partners. The Hothaps team welcomes independent use of the study protocols, but would be grateful for information about any planned, ongoing or completed studies of this type. Coordinated implementation of the protocols in multi-centre studies is also welcome. Eventually, the results of the Hothaps field studies will be used in global assessments of climate change-induced heat exposure increase in workplaces and its impacts on occupational health and productivity. These results will also be of value for the next assessment by the Intergovernmental Panel on Climate Change (IPCC) in 2013.

Indoor Thermal Performance of Ventilated Dwellings Using Fly Screens in the Hot-Humid Climate of Chennai, India

In a hot-humid tropical climate, indoor thermal performance can be enhanced by comfort ventilation. Indoor ventilation depends upon building opening size. But risks involved in providing openings include ingress of mosquitoes and insects which thrive in the tropical climate. A practical and prevalent option to prevent insects in ventilated dwellings of the tropical, hot-humid city of Chennai, India is through the use of fly screens. Fly screens, when used over openings, prevent a certain quantum of solar radiation and wind from entering inside the rooms. Reduced direct solar radiation prevents the indoors from heating up, while reduced wind movement prevents the cross ventilation. Therefore, it is important to know the indoor thermal performance of ventilated rooms in the presence of fly screens with changing opening sizes. The criterion to evaluate indoor thermal performance in this paper is indoor air temperature. The aim of this research is to investigate the influence of fly screens on openings with varying sizes, in a naturally ventilated dwelling in the hot-humid climate of Chennai, India, during the summer period. The results of the study show that fly screens raise the indoor air temperature when openings are in the range of 100% to 35% of the room floor area. There is no significant change in the indoor air temperature when the opening sizes are less than 30% of the room floor area.

Life on the edge – High levels of genetic diversity in a cliff population of Bertya ingramii are attributed to B. rosmarinifolia (Euphorbiaceae)

Wind-facilitated migration of new genotypes into small, geographically disjunct populations should buffer them against local extinction. Bertya ingramii, a monoecious, wind-pollinated shrub, is restricted to three populations in a 4 km 2 area in eastern Australia. Populations are separated by deeply dissected gorges where it is unlikely that seeds are exchanged but where wind movement may facilitate pollen dispersal. Using 156 highly polymorphic ISSR markers, we found moderate genetic variation within and among populations of B. ingramii and less genetic diversity in a nearby and small population of the widespread Bertya rosmarinifolia. The smallest population of B. ingramii (<30 plants) had the highest genetic variation (65% polymorphic markers, Shannon Information Index = 0.30). AMOVA and a Bayesian analysis showed that molecular variance was equally distributed within and among populations suggesting that gene flow is as limited within as in among populations. Genetic distances between populations were only weakly explained by their relative geographic distances (mantel test, R 2 = 0.21, P = 0.001) but the distribution of private bands, the departure from Hardy–Weinberg equilibrium, and a UPGMA tree showed that the smallest population of B. ingramii was generally more similar to an upstream population of B. rosmarinifolia. Thirty-eight percent of bands in this small population of B. ingramii were exclusively shared with B. rosmarinifolia. This covert hybridisation may have been an ancient event but may be responsible for contemporary declines in germination and establishment in B. ingramii. The conservation implications are amplified by the endangered status of B. ingramii.

Genetic programming for real-time prediction of offshore wind

Wind speed and its direction at two offshore locations along the west coast of India are predicted over future time-steps of 3 to 24 hrs based on a sequence past wind measurements made by floating buoys. This is done based on a relatively new soft computing tool using genetic programming. The attention of investigators has recently been drawn to the application of this approach that differs from the well-known technique of genetic algorithms in basic coding and application of genetic operators. Unlike most of the past works dealing with causative modeling or spatial correlations, this study explores the usefulness of genetic programming to carry out temporal regression. It is found that the resulting predictions of wind movements rival those made by an equivalent and more traditional artificial neural network and sometimes appear more attractive when multiple-error criteria were applied. The success of genetic programming as a modelling tool reported in this study may inspire similar applications in future in the problem domain of offshore engineering, and more research in the computing domain as well.

Adaptive growth of Tamarix taklamakanensis root systems in response to wind action

Root distribution and characteristics were investigated on a 70-year-old Tamarix taklamakanensis individual through uprooting. Rooting depth was restricted by water table, and root morphology adapted to resist the wind movement associated with shallow rooting. Root systems had more structural root mass and length on the leeward side than the windward side of the tree relative to the prevailing wind direction. Additional resistance to wind bending can occur as a result of increased thickening of the lower stem along the axis of the prevailing wind direction, and in T. taklamakanensis, this thickening is greater on the lee side of the stem. We conclude that increased root distribution and thickening of the lower stem on the leeward are an important strategy for T. taklamakanensis in response to wind action in the hinterland of Taklimakan Desert.

Simulated impact of altered Southern Hemisphere winds on the Atlantic Meridional Overturning Circulation

Previous work has suggested that the strength and latitudinal position of the Southern Hemisphere (SH) mid‐latitude westerly winds has an important impact on climate and the Atlantic Meridional Overturning Circulation (AMOC). We probe this hypothesis by conducting ensembles of experiments using the GFDL CM2.1 coupled ocean‐atmosphere model with altered SH wind stress. We find, consistent with previous work, that enhanced (reduced) and poleward (equatorward) displaced SH westerly winds lead to an AMOC intensification (weakening). While the AMOC takes more than a century to respond fully to the altered SH winds, initial effects in the North Atlantic can occur within a few decades. The AMOC changes generate SST and surface air temperature responses in the North Atlantic and adjacent continental regions. In the Southern Hemisphere, the atmosphere responds to the altered ocean circulation with a further strengthening and poleward movement of the SH winds, thereby constituting a modest positive feedback.