This article presents results of model tests of pressure distributions over interior and exterior surfaces of a utility building model carried out in an boundary layer wind tunnel. The tests were carried out taking into consideration different variants of solidity ratio coefficient values of the structure’s side walls. The main aim of the analyses was to determine the influence of the solidity ratio coefficient values of the side walls on the wind pressure distribution over the interior and exterior surfaces of the object. Four configuration variants of the side walls were taken into account for two directions of air flow – perpendicular to the gable wall and perpendicular to the side wall. The achieved results were analysed.

This paper summarizes results of wind tunnel tests of a high-rise building placed in Warsaw city centre. Aerodynamic laboratory studies were accomplished in a boundary layer wind tunnel. The main objective of the research was to determine the distribution of the mean wind pressure coefficient over the building’s external surfaces as affected by the aerodynamic interference between the structure and its immediate city surroundings. Interference coefficients of wind pressure and global wind forces acting upon the surfaces of the building walls and roof were calculated. The aerodynamic studies showed a significant influence of objects located nearby on the wind load that the high-rise building structure surfaces are subjected to.

This paper deals with the derivation of similarity criteria for the phenomenon of railway wagons rolling over when exposed to strong crosswinds. Utilizing these criteria, the authorial method for the determination of the aerodynamic coefficient of the rollover moment is also presented in the paper.

Wind tunnel testing is sometimes achieved at reduced scale. Doing so, wind engineers must consider the similitude rules for giving results at full scale. These rules are deduced from the basic laws of Physics, for their theoretical part, and based on practical state of the art methods for wind tunnel application. A wide overview of this important part of wind engineering is given in this paper

This paper describes methods for testing model wind turbines in wind tunnels based on published data and the experience gained by the author through having tested many different wind turbines in wind tunnels at the University of Auckland. Wind tunnels can be used to determine the performance of small wind turbines at full scale, or larger wind turbines at reduced scale. Such experiments need to be done with care as one needs to be aware of issues regarding blockage, the effect of Reynolds number, and being able to control the speed of the turbine so that is power coefficient can be obtained over a suitable range of tip speed ratios. With rotating machinery, it is also important to have a regard to safety, so the models have to be made with care and a stress analysis carried out to ensure that the material properties are not exceeded during the testing. It is found that wind tunnel testing is a useful way of determining experimentally the performance of wind turbines in order to predict the power output, and for obtaining data to validate theoretical or numerical model predictions.

This paper presents the method and results of a geographical altitude factor calculation to determine wind loading Calt at 9 meteorological stations in the Transcarpathian region. According to state building standards В.1.2-2:2006, the coefficient of geographical altitude is used to calculate wind pressure while positioning the building site at an altitude of up to 0.5 km it equals 1, at altitudes higher than 0.5 km, it is determined using the formula Calt = 4H–1. With the help of the suggested method, according to 23 directions and high wind coefficients, as well as data of meteorological observations from 1955−2005, the coefficients of geographical altitude were calculated to determine wind loading in July and January for each residential site, the peaks and mountain passes for the Transcarpathian region of Ukrainian Carpathians.

This paper considers the dependence of pressure fields on surfaces of rectangular prisms obtained from wind tunnel experiments on boundary layer characteristics. Six different variants of boundary layer flows were simulated in the wind tunnel. The qualitative coefficients of correlation Rs between the wind pressure coefficient Cp or its standard deviation σp and parameters describing boundary layer flows (wind speed profile, turbulence intensity profile, power spectral density) were estimated in order to determine how wind parameters influence surface pressure. Five rectangular prisms were placed in the wind tunnel. The following ratios of prism dimensions were adopted: D/B/H = 1:2:20 (R5); 1:2:10 (R3); 1:2:5 (R1); 1:4:20 (R4); 1:4:10 (R2).

An analysis of the response of steel chimneys to wind action is presented in this paper. The approaches presented in the Polish standards and in Eurocode 1 referring to steel chimneys and wind action are shown here. Comparisons of along-wind and crosswind action according to these procedures are made. Responses to the wind action, i.e. displacements of the top of each chimney, are compared. Real chimneys were analyzed. In almost every case, significant vibrations due to vortex excitation was observed. Structural data was obtained from the literature. All chimneys and wind actions were modelled in FEM system – Autodesk Mechanical Simulation 2013. Very significant differences of the crosswind response were observed when analyzing two approaches proposed by Eurocode. Lateral displacements were larger than longitudinal displacements in many analyzed cases.

This paper focuses on the aerodynamic drag force that acts on a long cylinder standing up to aerodynamic wind in the critical regime of the fluid flow. The core problem addressed here is how surface roughness of a high level and further increase of that level affects the drag. The research is based on computer simulations using the Discrete Vortex Method. A meshless version of the method was applied in order to let the boundary layer form freely in the way of a direct computer simulation. Fundamental ideas behind the Discrete Vortex Method, the original research program and the obtained results are presented. The main conclusion is that a small level of surface roughness may be neglected in engineering estimations.

This paper presents a comprehensive review of the research into windborne debris using. It introduces the components of the typical debris risk model - wind field model, debris generation model, debris trajectory model and debris impact model - and reviews the research that has been done in each of these constituent areas. The majority of this research has focussed on understanding the fundamental physics of debris flight, using both experimental and computational approaches to derive analytical and empirical models. This fundamental physics must be viewed, however, within a probabilistic framework that allows the risk to be assessed in a relevant manner. Much of the research relates to hurricane hazard in the USA , however windborne debris is clearly a threat to the urban environment duringEuropean wind storms. The way that FEMA ’s HAZUS ®MH hazard assessment tool has brought natural hazard modelling into the engineering context is viewed as an approach that could be adapted for both mitigation and design in a European context.

The present study examines the wind-induced behaviour of free-standing membrane canopy roofs with various types of roof-supporting systems and presents wind force coefficients for designing such roofs. The effects of roof deformation and choice of roof-supporting system on wind force coefficients are investigated. The characteristics of wind-induced responses of the roofs are taken into account for improving the wind force coefficients that we previously proposed based on the results of wind tunnel experiment with rigid roof models.

The present paper discusses the mechanism of the wind-induced scattering of permeable unit flooring decks loosely laid on the rooftops and balconies of high-rise buildings. Firstly, the scattering mechanism of decks was investigated, based on a blowing test using a blower and actual decks. Subsequently, a simulation model was constructed for estimating the internal pressures under the decks (pressures acting on the bottom surface of decks) obtained from a wind tunnel experiment – this is based upon the unsteady Bernoulli equation and the time history of external pressures on the rooftop and balconies. Combining the simulated internal pressures and the experimentally obtained external pressures, the time history of net wind pressures acting on the decks were computed. Finally, the threshold wind speed of scattering (scattering wind speed) was obtained by applying the scattering mechanism to the simulated time history of the net wind pressures.

A large number of existing bridges need to be rehabilitated due to increasing traffic and/or loading requirements and also corrosion action. In this paper, a procedure is presented for estimating the ultimate capacity of a steel bridge over the Danube in Bratislava – Old Bridge (built in 1945). The development of a simplified Finite Element Model (FEM ) and basic modal parameter calculations preceded the experimental investigations of the bridge via static and dynamic in-situ loading tests, so that the main assumptions adopted in the FEM were assessed through comparison between measured and predicted dynamic and modal parameters of the bridge structure. The bridge structure computational model was then optimized by structure variables (primarily, steel structure joints mass and corrosion grade) to achieve the minimum differences between the experimental and theoretical results. The calibrated FEM with the optimal combinations of the mentioned variable values were defined and finally used for structure calculations and for strengthening the design of the real bridge structure.

The static and dynamic deformation monitoring of engineering structures has been a matter of concern for engineers for many years. This paper provides a review of research and development activities from 1993 in the field of bridges, tall buildings, and tower health monitoring using GPS. Firstly, early pioneering applications of GPS to measure the structural vibrations of these structures and the assessment of the measurement accuracy of GPS are briefly described. The progress on monitoring the displacements and dynamic characteristics of bridges and tall structures, caused by traffic loads, wind, and the combined influence of solar radiation and daily air temperature variations, is then presented.

The paper concerns dimensional analysis and the theory of model similarity of physical phenomena. At the beginning of the considerations, basic notions, definitions, relationships and fundamental principles of the issues to be analysed has been presented. Next, Buckingham’s Π-theorem of dimensional analysis and theory of similarity as well as authorial generalized theorems Π of this field of interest have been derived. A separate chapter has been devoted to the problem of the nature of physical phenomena occurring in the mechanics of continuous or discrete material mediums. At the end of the paper, an example of the determination of similarity numbers in the case of a system with one degree of freedom at mechanical and kinematic excitation have been given.

The present analysis undertakes the problem of surface wind over topography. The main focus is placed upon the effect of oncoming wind oscillations on the velocity field structure around a single sinusoidal shaped 2D hill. Additional effort has been undertaken to recognize the inflow gust influence on the surface shear stress related to the mechanism of wind induced erosion. Numerical simulations have been performed through the use of the phase-averaged form of RNG version of k-ɛ turbulence model. Experimental verification of numerical data has been done in wind tunnels equipped with devices generating unsteady wind boundary layers. The main findings of the simulations reveal: a strong dependence between the characteristics of inflow periodicity and the structure of vortices of the separation region; the mean position of the reattachment point; the phase averaged velocity field; skin friction variability downstream from the hill. The results have significant implications for the prediction of sand transport in unsteady winds.

Large displacements caused by temperature loads are a significant problem in the design and operation of concrete tram surfaces. There is frequently observed damage to expansion joints between slabs induced by high displacements as well as aging processes. As a result, water penetrates through cracked expansion joints causing structural degradation. Tests performed in situ indicate that polymer flexible joints may be used as concrete slab connections in concrete tram surfaces. Besides sealing, this technology allows transferring loads within large deformation states, additionally, rotation angles of slab edges are decreased, reducing the risk of damage to connections. This work analyzes the structural behaviour of a section of a tram surface connected by polymer flexible joint technology. A FEM numerical model in was constructed in Abaqus 6.12 with the analysis of thermal loads. This paper presents the analysis of deformation and stress distribution in structural elements, in cases of different constructional variants; the results are presented and conclusions are drawn.

A proposed assessment method for microclimatic conditions in urban structures is presented in the paper. The assessment model defines the quantitative and qualitative features of the study area. The three main elements of the urban environment – local climate, urban development, and the type of the area surfaces – are all evaluated. The proposed method constitutes an approximation. Parameters such as the location, shadow fall, or heat loss by the external surfaces of the building were not included.

This paper introduces a new climatic wind tunnel laboratory, which is one of the laboratories of the Institute of Theoretical and Applied Mechanics (ITAM ) of the Academy of Science of the Czech Republic. The tunnel is used for fundamental research in civil engineering, architecture, and heritage care and in other fields where wind effects appear along with other factors. The paper includes essential information about the interior layout of the tunnel, descriptions of the principal parts of the tunnel which were designed taking into account both the optimal flow characteristics together with the description of some facilities serving for the simulation of a strong wind, rain, freeze and heat radiation, and the modelling of the atmospheric boundary layer. A design for a rectangular contraction nozzle, based on a parabolic profile and extending the capacity of the wind tunnel is presented.

The design of low-rise buildings such that they can handle wind loads makes it necessary to accurately evaluate those wind loads, both on the structural framework and on the cladding/components. To this end, it is necessary to fully understand the characteristics of the wind near the ground around a building. This study sets out to develop a quantitative means of estimating the turbulence of the wind near the surface of the ground, based on field measurements obtained at different points across Japan. The surface roughness is evaluated based on several factors taken from a building information database. The relationship between these factors and the turbulence of the wind is discussed. The effect of the observation height, relative to the surface of the ground, on the turbulence is also investigated.

This paper presents a numerical analysis of the daylighting of exemplary office interiors. Simulation results were obtained using a radiance model. The following indexes: UDI, DF, DA, DSP were calculated and analysed for different solutions of building façade. The construction differs in the total thickness of the wall. Two cases were considered: 25 cm and 50 cm opaque sections. Additionally, window magnitude changes from 0.36 m2 to 1.44 m2, with different shapes and locations relative to the centre of the wall. The idea of the work was to find out the architectural solution of the transparent element (geometry and magnitude) taking into account two criteria: decreasing solar heat gains; increasing the daylight utilisation factor. The results are presented in the form of a diagram of daylight distribution as well as average values of visual comfort indexes. The highest values of each indicator (DF, DA and DSP) were obtained for a centrally placed window 1.44 m2. However, the results of useful daylight index UDI depend on the assumed range and it is not easy to identify a relationship between window size and daylight efficiency.

This paper presents an acoustic study of the auditorium hall located in the proposed building of the Applied Acoustics Laboratory of Cracow University of Technology. The study shows a comparative analysis of two solutions to the acoustic adaptation of this room. The aim of this study was to demonstrate that with a given room shape and finishing materials, it is possible to optimize the sound quality of the interior through changes to some architectural details, for example, by the adequate formation and arrangement of finishing elements.

In the search for new renewable energy sources, photovoltaic systems and solar thermal collectors have become more common in buildings. With increased efficiency and demand for energy, solar power has also become exploitable at higher latitudes where snow is a major load on buildings. For flat roofs, one usually expects approximately 80% of the snow to be eroded off the roof surface. Installing solar panels would change this since the flow pattern and wind conditions on the roof are affected by their presence. This study shows the erosion of sand particles from underneath solar panels of various configurations associated with different wind velocities. The pattern of erosion is used to determine the relative friction velocity, u*REL, of the wind on the roof. This value is the friction velocity on the roof relative to the friction velocity on a flat roof without solar panels. The experiments, conducted in a wind tunnel, showthat the area where u*REL is 0 and where it is expected that sand and snow will accumulate in case of an upwind particle source and decrease with increasing distances between roof and solar panel. It is also shown that a larger gap between the solar panel and roof surface creates larger erosion zones, where u*REL > 1 for both wind directions. Since the erosion is closely linked to the air flow under the solar panels, and that higher air velocity increases the erosion, it is likely that a larger solar panel, extending higher into the free air flow would be desirable to avoid snow accumulation on a flat roof with solar panels. If the solar panel has large enough dimensions, the solar panels can be used as a deflector to decrease snow accumulation on flat roofs. With solar panels of the size in the current experiments, a building with a length smaller than the equivalent of x/L = 0.3 would have u*REL > 1 on most of the roof surface and would thus likely have a lower snow load than an equivalent float roof without solar panels.

This paper presents a new approach to determining the synergetic effects of environmental conditions and mechanical loading on the load bearing capacity of structural members. Cellular automata are used to estimate the residual strength of a RC section subjected to concrete corrosion. The evolution of interaction surfaces resulting from bending moments and axial force caused by a continuous degradation process is presented.

Transport and deviation of snow by wind induce many constraints on buildings, vehicles and industrial systems. A selection of questions from snow-wind engineering are presented in the paper. The experimental method that was undertaken to investigate these questions makes use of a large climatic wind tunnel, partly designed to address snow engineering problems at full scale: snow penetration in buildings, into ventilation systems of buildings and vehicles and snow or ice accretions on structures.

This paper gives an overview of current achievements where modern weather forecasting techniques are implemented for the assessment of especially ice and wind loadings on electrical overhead lines, TV towers, masts and similar infrastructure. Modern numerical weather prediction models (NWP ) incorporate far more details on e.g. cloud physics and dynamics than those generally necessary for regular weather forecasts. Such models describe in principle all physical and dynamical processes in the atmosphere in 3-D. In combination with detailed data on the physical properties of land and water surfaces, it is now possible to obtain realistic values of weather parameters related to wind, turbulence, precipitation and atmospheric icing down to a horizontal scale of a few hundred meters. Such models are therefore powerful tools for the planning and final design for various infrastructures in remote terrain where little or no weather data can provide sufficient bases for the establishment of extreme weather loads necessary for their design.

The influence of the ice accretion, angle of attack and Reynolds number on the flow field around iced cables of cablesupported bridges is not clearly understood. The Strouhal number is one of the most important parameters which is necessary for an analysis of the vortex excitation response of slender structures. This paper presents the method and results of wind tunnel investigations of the Strouhal number of stationary iced cable models of cable-supported bridges. The investigations were conducted in a climatic wind tunnel laboratory of the Czech Academy of Sciences in Telč. The methodology leading to the experimental icing of the inclined cable model in the climatic section of the laboratory was prepared. The shape of the ice on the cable was registered by photogrammetry and numerical evaluation. For the aerodynamic investigations, the iced cable model in a smaller scale was reproduced using a 3D printing procedure. The Strouhal number was determined within the range of the Reynolds number between 2.4·104 and 16.4·104, based on the dominant vortex shedding frequency measured in the flow behind the model. The model was orientated at three principal angles of wind attack for each of the Reynolds number values. In order to recognize the tunnel blockage effect, the Strouhal number of a smooth circular cylinder was tested. Strong agreement with the generally reported value in the subcritical Reynolds number range for a circular cylinder was obtained.

Lightweight tent structures are allowed under European codes to be designed for reduced snow load if the interior of a tent is appropriately heated. The dependence of the resultant snow load on snowfall rate is considered in this paper for such cases. A simple thermodynamic model of the heat flux is derived. Numerical simulation reveals the occurrence of a precipitation rate threshold value above which safety measure provided by heating becomes ineffective.

In this paper the probabilistic model of the snow accumulation on the roofs with height discontinuity was worked out, the decreasing coefficient for the snow load weight was received and the ways of their application in the designing were elaborated. The probabilistic model for impulse stochastic process of snowfall sequence was developed. Data from meteorological stations in Ukraine allow determination of statistical characteristics: average annual snowfall amount and exponential distribution of values of one snowfall. The law of intensity distribution of snow melting has been determined experimentally. The territorial zoning map of Ukraine by characteristic values of the snow load on the roofs that emanate heat was developed.