Measurements of the Hydrodynamic Lift and Drag Forces Acting on Riprap Side Slope

by A. F. Ahmed, Hydraulics and Sediment Research, Inst, Delta Barrage, Egypt,
F. S. El-Gamal, Hydraulics and Sediment Research, Inst, Delta Barrage, Egypt,

Document Type: Proceeding Paper

Part of: Fundamentals and Advancements in Hydraulic Measurements and Experimentation


Direct measurements have been made of lift and drag forces acting on a 20.1 mm spherical particle placed within the riprapped 1.5 H: 1 V side slope of a 10 m long channel which was protected with a rock layer of 1.5 diameter equivalent thickness. A specially fabricated electro-mechanical load beam cell comprising four identical strain gauges was applied, for various flow rates, which allowed simultaneous recordings of the hydrodynamic lift and drag forces acting on test particle. To establish the appropriate sphere diameter as well as its location at the level of maximum wall shear, preliminary experiments were conducted for various flow rates. In addition, in order to assess the significance of employing a spherical particle during these measurements, the load beam was used to measure the hydrodynamic forces acting on four different wooden blocks simulating real particle shapes. The force measuring equipment, basic techniques, calibration and experimental procedures as well as the results obtained are the subject of the present paper.

Subject Headings: Hydrodynamics | Riprap | Slopes | Particles | Drag (fluid dynamics) | Flow measurement | Load factors | Beams

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