Author(s): Claudia Pollak-Reibenwein; Anne Joeppen
Linked Author(s): Anne Joeppen
Keywords: Turbulence intensity; Acoustic Doppler Velocimetery (ADV); Vortex shedding; Vortex shedding frequency; Hydraulic model tests
Abstract: Since turbulence is prevalent in the natural environment as well as in many industrial equipments, it is necessary to understand how the presence of turbulence affects the mean velocity field of the flow and to attain profound knowledge of the interconnection between turbulence and flow velocity. Former studies demonstrated, that with decreasing turbulence intensities the vortex shedding frequencies of circular profiles under approaching flow conditions increase. In this regard the question came up whether a dependence between turbulence intensity and flow velocity could be recognized. Therefore hydraulic model tests in the laboratory of the Institute for Hydraulic and Water Ressources Engineering of Vienna University of Technology have been conducted in order to investigate this relationship. In the laboratory’s free-surface channel flow, a velocity field ranging from 10 cm/s up to 45cm/s, which was subject to varying turbulence conditions, was measured with an Acoustic Doppler Velocimeter (ADV). The obtained results clearly showed a dependence between turbulence intensity and flow velocity in contrast to similar measurements by Wang (1992), who quoted that the turbulence intensity is independent from the mean flow velocity.
Year: 2007