Print Email Facebook Twitter Report on measurements: Pressure and velocity fluctuations around a granular-bed element Title Report on measurements: Pressure and velocity fluctuations around a granular-bed element Author Hofland, B. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2001-12-01 Abstract The second chapter describes the general methodology of the research. It presents the key questions about the entrainment of stones from granular filters that are as yet unanswered. It also describes the aspects that are being regarded in the analysis in this report. In chapter 3 the measuring set-up is described. The following two chapters present the experimental results. Chapter 4 describes the pressures on and flow around a solitary bed-mounted cube. This configuration can be regarded as a model for a very exposed stone, subject to a flow with low turbulence intensities. This simple configuration (already with a complicated flow-field) can also be calculated relatively easily. This generates the possibility to obtain even more information about the entire velocity and pressure field. Chapter 5 presents the measurements that have been done on the bed-mounted cube as part of a (one layer thick) granular filter. The protrusion of the cube has been varied in order to examine the influence of the stone position on stability. In chapter 6 some further possible analyses on the measurements are described. Finally, in chapter 7 some conclusions are drawn from the results that have been gathered so far. SOME RELEVANT CONCLUSIONS - It was shown that both the fluctuating and the mean pressures are influenced by the position of the cube. This cube can be regarded as a model of a stone. - The average pressures on the bed mounted cube follow the p = Cpü^2 law, with a positive C for the upstream side and a negative C for the top and the lee-side. - Pressure on top of solitary bed-mounted cube has a very high intensity and a maximum at u/f = 15. Subject granular filtermeasurementsbed stabilitystability To reference this document use: http://resolver.tudelft.nl/uuid:7aec6bdc-77e6-4299-84fa-73b86af8f2cd Publisher TU Delft, Department of Hydraulic Engineering Part of collection Institutional Repository Document type report Rights (c) 2001 TU Delft, Department of Hydraulic Engineering Files PDF Hofland2001a.pdf 14.71 MB Close viewer /islandora/object/uuid:7aec6bdc-77e6-4299-84fa-73b86af8f2cd/datastream/OBJ/view