The influence of the flow turbulence on the flow structure behind a sphere

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.

Flow turbulence intensifies processes of momentum, heat and mass transfer in a flow or on surfaces immersed in such a flow. This paper presents results of experimental investigations of the influence of the inflow turbulence on the velocity and the shear stress distributions behind the sphere for a selected distance. It is assumed that a flow structure behind the sphere is dependent on the flow structure in a boundary layer on a sphere that is under the inflow turbulence control. The inflow turbulence changes the pattern of distributions of the average pressure and its turbulent fluctuations on the sphere surface. Because of that the flow behind the sphere becomes dependent on the intensity of the flow turbulence in front of the sphere area. Radial profiles of the average velocity behind the sphere becomes more flat as the inflow turbulence increases. The shear stress profiles and the profiles of velocity fluctuations are also modified by the inflow turbulence level. When the intensity of the inflow turbulence increases the radial profiles of uv correlations representing the mixing properties of the flow behind the sphere get more flat but reach larger radius.