Applied Mechanics and Materials Vol. 820

Abstract: The Venturi effect has been defined as the increase in fluid speed or flow rate due to a decrease of the flow section. In the present paper the wind speed conditions in passages between triangular buildings with different distances are studied with Computational Fluid Dynamics (CFD) to investigate the extent to which the Venturi effect is present in the passages. In this paper are considered eight different variants of relative positions of the two high-rise buildings. The variable is a distance between towers. They are investigated maximum wind velocities and the point at which the maximum velocity occurs for each from these variants.

Abstract: The article, in the context of sustainable urbanism, reflects current tendencies of small urban wind power plants implementation into municipalities. There is an emphasis on wind as one of the aspects of architectural design and urbanism. Due to extensional interdisciplinarity of the examined phenomenon, the article captures a wider framework of the issue. The sustainability objectives in the creation of settlements - housing environment are emphasized. By the overview of wind turbines and selected research papers article demonstrates the current state of the subject. Yet the research points out that dynamic pedestrian comfort is not being taken into account and chosen geometries are not suitable. The article outlines visions and possibilities of implementation of small urban wind power plants while correctly using tools, techniques and qualitative and quantitative parameters.

Abstract: This paper deals with pressure measurement on the surface of the elliptic cylinder. Aerodynamic properties are not same for different shape of the building. Therefore it is important complex experimental measurement for complicated shape. Aim of the article is to understanding the wind loads on building for various arrangements. Results are external pressure coefficients of elliptic model for various rotations. Conclusion of the experiment is to find optimal and critical wind direction for isolated building. This research will be background for future work of interference effect.

Abstract: Atmospheric Boundary Layer (ABL) is the lowest part of the troposphere. The main feature of the Atmospheric Boundary Layer is the turbulent nature of the flow. The thickness of the boundary layer, formed by flowing air friction on the earth’s surface under various conditions move in quite a wide range. ABL is generally defined as being 0.5 km above the surface, although it can extend up to 2 km depending on time and location. The flow properties are most important over the surface of solid objects, which carry out all the reactions between fluid and solid.

Abstract: Wind can be beneficial for example in seafaring, flying or energy production, as well as it can have negative impact. This negative effects can be prevented by deep analysis and experimental methods. Verification of buildings and structures on the model before implementation contributes to saving funds and also has an impact on the environment. In our country, the basic guide for assessing the effects of wind on the buildings is Slovak Technical Standard STN EN 1991-1-4, which provides guidance for determining wind loads in structural design of buildings. In the case of assessment of buildings that are beyond the scope of this standard, we can obtained by experimental measuring using wind tunnel or calculate it numerically, using some commercial software.

Abstract: The aim of the paper was to define the input options over the boundary layer, as the entrance boundary conditions for simulation in ANSYS. The boundary layer is designed for use in external aerodynamics of buildings (part of the urban structure) for selected sites occurring in the territory of the Slovak Republic.

Abstract: In this article are described the results from testing profile of atmospheric boundary layer in BLWT (Boundary layer wind tunnel) in Florence (Prato), Italy with emphasis on comparison of the results with simulations in CFD (Computational fluid dynamics) software OpenFoam. The values are compared with calculated values from EuroCode.

Abstract: This paper is concerned with wind influence on pedestrians in different buildings underpasses where with using of Computational Fluid Dynamic (CFD) is made study about proportion of buildings and underpasses affecting velocity and so pedestrian comfort in passage. For simulation of wind flow is used OpenFOAM software with k-epsilon model, which is in many papers represents as one of the best and most reasonable model for evaluation pedestrian comfort.

Abstract: At the small town of Silsoe, UK , under the leadership of engineer Richards the model was made up with edge of the cube 6 m, used for research of wind on the model. Cube named Silsoe took over many laboratories in the world and diminished cube was tested in the wind tunnel. The aim of our study was to compare recently built the wind tunnel Faculty of Civil Engineering in Bratislava with other sites in the world. Suitable for this purpose served just cube model Silsoe of the edge of 200 mm, which was tested in the wind tunnel of Faculty of Civil Engineering and subsequently also in the workplace at VZLU Prague. The model coefficients were measured the pressure on the cladding of cube and compared with the other measurements. The test results are presented in this paper.

Abstract: Ability to resist of high temperature impacts during fire is not based exclusively on ignitability of building materials. At the present time, fire resistance is declared mainly through fire tests, but numerical procedures for the determination of fire resistance also represent an effective alternative in this field. Using calculation methods for the determination of ceiling structure fire resistance on the basis of timber is subject of the submitted paper. The main objective of this paper is to demonstrate the fact that timber, or products from it, are building materials capable to resist impacts of fully developed fire for the period of more than 60 minutes in spite of their flammability. Applicability of these results in selected countries of Europe can be seen from the list of requirements.