Interference Between a Circular Cylinder and a Plane Wall Under Waves

✍ Scribed by A. Jarno-Druaux; A. Sakout; E. Lambert

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 444 KB
• Volume: 9
• Category: Article
• ISSN: 0889-9746
• DOI: 10.1006/jfls.1995.1011

✦ Synopsis

The flow around a circular cylinder placed close to a plane boundary under water waves and the correlated hydrodynamic forces have been investigated. The Keulegan-Carpenter number was fixed at 4.9 and the Reynolds number at 1800 . The study comprises laser Doppler velocity measurements in the vicinity of the cylinder for two typical gap-todiameter ratios, (e / D). In the first case, the gap between the cylinder and the plane boundary was lower than the thickness of the oscillatory boundary layer on the wall. In the second case, the cylinder was placed far from the wall boundary layer. Distinct vortex flow regimes have been observed and different mechanisms of wall effect have been pointed out in the two cases. The hydrodynamic forces exerted on the cylinder were measured in a range of (e / D) from 0.04 to (1 \cdot 5). Force measurements and flow regimes were correlated and the variation of the force coefficients was interpreted by using a parameter involving the thickness of the oscillatory wall boundary layer. Force coefficient variations obtained in purely oscillatory flow studies may be similarly interpreted.