Grzegorz Bosak

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.

Before the widespread use of computers, the only way to design a structure with complex shape was to build a prototype model and perform the necessary tests. Nowadays, designers are able to create an accurate and complex engineering design by effective mathematical models. The paper describes the numerical analysis of cooling tower carried out by a finite element method. The FEM analysis was performed with Lusas software. The cooling tower represents the real structure located in Kozienice, Poland. During the calculations, different load cases based on wind tunnel tests were taken into account. The evaluation of the influence of different wind directions and configuration of obstacles on internal forces and displacements were analyzed. Proper dimensions, material proprieties and method factors were applied to the model. In the further part, the dynamic evaluation was presented. The Eigen modes with corresponding values and shapes were created and described. Estimation of impact of dynamic wind action on the object will be also released. Time history of amplitude and displacements was attached. As a result of the dynamic studies, the dynamic evaluating indicator was calculated.

This article outlines static and dynamic analyses of the viewing platform in Trzęsacz. The steel construction consists of two parallel lattice girders placed on concrete columns. The elements of the girders are made of tubular profiles. Ultimate limit state and serviceability limit state criteria were fulfilled in accordance with algorithms from Eurocodes. This paper also presents an analysis of the platform’s dynamic responses from rhythmical motion caused by human activity. The results of these calculations were checked with the comfort levels of people standing in the platform during the vibrations. Robot Structural Analysis Professional was used for the linear load case of static analysis and modal analysis.

This article presents description and results of an investigation using PIV for measuring wind velocity fields in front of and behind bulkheads made from nets of different solidity ratios. The basic aim of the work is to determine the characteristic features  of the wind velocity field on the windward and leeward sides of nets of different solidity ratios and to present an example of the usage of a PIV system in tests in an aerodynamic tunnel. The tests were performed in a mini aerodynamic tunnel especially prepared to test the PIV system. In the work, the regulations of measurement by means of a PIV system are presented, the main elements of the system are characterised and the main advantages and difficulties of realising measurements using this type of technique are described. 

Keywords: wind tunnel tests, PIV system, wind velocity field, solidity ratio, permeable wind curtain

Pomiar systemem piv pola prędkości wiatru przed i za przegrodą wykonaną z siatki o różnym współczynniku wypełnienia

Streszczenie

Artykuł przedstawia opis i wyniki pomiarów systemem PIV pola prędkości wiatru przed i za przegrodą wykonanej z siatki o różnym współczynniku wypełnienia. Podstawowym celem pracy jest określenie charakterystycznych cech pola prędkości wiatru po stronie nawietrznej i zawietrznej siatek o różnych współczynnikach wypełnienia oraz przedstawienie przykładowego wykorzystania systemu PIV w badaniach w tunelu aerodynamicznym. Badania przeprowadzono w mini tunelu aerodynamicznym przygotowanym specjalnie do testowania systemu PIV. W pracy ponadto przedstawiono zasady pomiaru systemem PIV, scharakteryzowano główne elementy sytemu oraz opisano podstawowe zalety i trudności realizacji pomiarów tego typu techniką.

Słowa kluczowe: badania w tunelu aerodynamicznym, PIV system, pole prędkości wiatru, współczynnik wypełnienia, przewiewne zasłony

The cooling tower can be classified as a special structure, both in terms of reliability and size. The collapse of such a large tower, located closely to other buildings, may result in very serious consequences. It seems that special attention should be paid during design process of this kind of structures. Despite the increase in cost, the additional analysis and studies are indicated and also may raise reliability. The article presents the influence of wind action on the cooling tower. It consists of the studies on the issue of aerodynamic interference performed in the wind tunnel. The attention was particularly focused on the influence of the wind pressure on the shell of cooling tower, and on variability of these pressures on the surrounding objects. Making an adequate scale model, configuration of measuring equipment and an execution of wind tunnel tests will be described in this paper. The research was concentrated on measuring the pressure coefficients on the cooling tower surface in single situation and interference situations.

The paper summarizes the wind tunnel tests of original acoustic panels located on the block buildings roofs near edge of building roof and walls. Performed investigations had two main goals: 1. Verification of resistance of the panels at their connecting members at high air flow velocities; 2. Determination the set of aerodynamic force coefficients, obtained from measured wind pressure distribution on the façade panel surfaces in two opposite wind directions, was the main aim of the work.

This paper summarizes results of wind tunnel tests of a non-standard stadium roof. 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 net pressure coefficient over the stadium roof surfaces as affected by the aerodynamic interference between the stadium structure and a large oval sports event hall, located nearby. Interference coefficients of wind pressure and global wind forces acting upon the surfaces of the stadium roof were calculated. The aerodynamic studies showed a significant influence of the oval Atlas Arena sports-event hall on the wind load subjected to the stadium structure.

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.