The model of a hyperboloid shaped object was measured by means of 2D Particle Image Velocimetry in the Wind Tunnel with simulated atmospheric boundary layer. The model was tested in a subcritical range of Reynolds number. Various planes in a wake of the model were captured. One was set in the model axis and perpendicular to the ground and the averaged velocity field of this measurement revealed a possible arch vortex behind the model. Next, several planes perpendicular to the ground were measured. The averaged velocity field showed two symmetrical formations. From these measurements, the shape of the arch vortex was estimated.

Abstract. This paper deals with flow around a bluff body of hyperboloid shape. It combines results gathered in the course of research by means of Particle Image Velocimetry (PIV). The experiments were carried out by means of low-frequency 2D PIV and the Reynolds number was 43 000.

This paper deals with flow around a bluff body of hyperboloid shape. It consists of results gathered in the course of research by means of Particle Image Velocimetry (PIV). The experiments were carried out by means of low-frequency 2D PIV in a range of Reynolds numbers from 40000 to 50000. A hyperboloid-shaped model was measured in a wind tunnel with a modelled atmospheric boundary layer (and additionally, in a low-speed wind tunnel with low turbulence). The model was tested in a subcritical range of Reynolds numbers and various planes in a wake of the model were captured with the intention of getting an estimation of 3D flow structures. The tunnel with the modelled atmospheric boundary layer has a high rate of turbulence, so the influence of the turbulence of incoming flow on the wake could be outlined. The ratio of the height of the model to a thickness of the modelled boundary layer in the tunnel was 1/3, meaning the turbulence in the boundary layer strongly influenced the flow around the model; it suppresses the wake which leads to a lot shorter area of recirculation than low turbulence incoming flow would cause.

A subject of an experimental fluid mechanics task was measurement of flow around hyperboloid-shaped cooling tower. Experimental part was provided by means of 2D Particle Image Velocimetry (PIV). The contribution contains results from PIV measurements in a range of Reynolds numbers varying from 43000 up to 53000. The tunnels used for the measurement were two different types: Low Speed Wind Tunnel of Eiffel type (LSWT) with low rate of turbulence intensity and Boundary Layer Wind Tunnel (BLWT) with high rate of turbulence intensity.

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