Author(s): Sevket Cokgor; E. Beyhan Yegen; Bihrat Onoz; İSmail Albayrak
Linked Author(s):
Keywords: Turbulence; Rough bed; Statistics; Acoustic doppler
Abstract: Several disciplines such as mechanical, aerospace, and hydraulic engineering etc. have considerable engineering interest in turbulent boundary layers over roughness elements. In this study attention is focused on statistical properties of turbulence characteristics over relatively large random roughnesses. The data of velocities over rough bed have been analysed through a statistical perspective. A three component acoustic doppler was used for obtaining the measurements of velocity. Experiments show that the vortices which form in the holes between roughness elements are key to the process of flow rush into the holes between the elements. In the present study a statistical analysis is performed so as to support the experimental findings. The histograms of the time series of longitudinal and vertical velocities over the roughness elements have been drawn and the parameters of these time series have been given. The correlation between the shear stress on a horizontal plane right over the roughness elements and momentum flux through this plane is also investigated. Interpretations of the phenomena dependent on statistical findings are made.
Year: 2007