Boundary-layer flow around a submerged circular cylinder induced by free-surface travelling waves

1996 ◽  
Vol 316 ◽  
pp. 241-257 ◽  
Author(s):  
B. Yan ◽  
N. Riley

We consider the fluid flow induced when free-surface travelling waves pass over a submerged circular cylinder. The wave amplitude is assumed to be small, and a suitably defined Reynolds number large, so that perturbation methods may be employed. Particular attention is focused on the steady streaming motion, which induces circulation about the cylinder. The viscous forces acting on the cylinder are calculated and compared with the pressure forces which are solely responsible for the loading on the cylinder in a purely inviscid flow.

1998 ◽  
Vol 374 ◽  
pp. 173-194 ◽  
Author(s):  
B. YAN ◽  
N. RILEY

Viscous flow about a circular cylinder that is submerged beneath free-surface travelling waves is considered. The wave amplitude is assumed small and results are presented for a wide range of Reynolds number. Particular attention is focused on the second-order time-averaged flow that manifests itself as a circulatory motion about the cylinder. The paper complements earlier work on this problem by Yan & Riley (1996) in the large Reynolds number, boundary-layer, regime and Riley & Yan (1996) in the inviscid flow limit, and makes a comparison with experimental work by Chaplin (1984) possible.


1996 ◽  
Vol 7 (6) ◽  
pp. 545-558 ◽  
Author(s):  
M. F. Wybrow ◽  
N. Riley

Oscillatory flow over a circular cylinder, or part-cylinder, placed on a plane boundary, when the Strouhal and streaming Reynolds numbers are large, is considered. The solution is developed in matching inner and outer boundary layers. A steady streaming motion in the outer layer can lead to a net flow away from the cylinder along the plane boundary. A simple experiment substantiates this prediction, and the implications for bed-scouring are examined.


Author(s):  
D. V. Evans

AbstractIn this paper the effect of surface tension on water waves is considered. The usual assumptions of the linearized theory are made. A uniqueness theorem is derived for the waves at infinity for a general class of bounded two-dimensional obstacles in a free surface by means of an energy argument. It is shown how the wave amplitude at infinity depends on the prescribed angle at which the free surface meets the normal to the obstacle. The particular case of a heaving half-immersed circular cylinder is considered in detail, and an expression obtained for the velocity potential in terms of a convergent infinite series, the coefficients of which may be computed.


1965 ◽  
Vol 22 (2) ◽  
pp. 337-346 ◽  
Author(s):  
W. W. Wood

Integral relations are derived for steady, incompressible recirculating motions with small viscous forces. The circuit time of a fluid particle on a closed streamline in steady, inviscid flow is shown to be the same for all the closed streamlines on a surface of constant total head.The discontinuities of velocity and velocity gradient that occur in the motion of inviscid fluid filling a closed, rotating cylinder set in a rotating support with the two rotation axes slightly misaligned are then investigated.


2018 ◽  
Author(s):  
H. R. Díaz-Ojeda ◽  
L. M. González ◽  
F. J. Huera-Huarte

The aim of this paper is to evaluate how much affects the presence of gravity and free-surface to a flexible structure in a classical fluid structure interaction (FSI) problem typically found in off-shore problems and other oceanic applications. The base problem selected is the Turek benchmark case where a deformable plate is attached to the wake of a circular cylinder. To focus on the differences of considering free surface, a simple geometry has been selected and two different situations have been studied: the first one is the classical Turek benchmark, the second is a similar geometry but adding gravity and free surface. The free surface problem was studied placing the structure at different depths and monitoring the deformation and forces on the structure.


1997 ◽  
Author(s):  
Bruce S. Rosen ◽  
Joseph P. Laiosa

The SPLASH free-surface potential flow panel code computer program is presented. The 3D flow theory and its numerical implementation are discussed. Some more conventional applications are reviewed, for steady flow past solid bodies, and for classical linearized free-surface flow. New free-surface capabilities are also described, notably, steady nonlinear solutions, and novel unsteady partially­nonlinear solutions in the frequency domain. The inviscid flow method treats both free-surface waves and lifting surfaces. The calculations yield predictions for complex interactions at heel and yaw such as wave drag due to lift, the effect of the free­surface on lift and lift-induced drag, and unsteady motions and forces in oblique or following seas. These are in addition to the usual predictions for the simpler effects considered separately, for example double-body lift and induced drag, and upright steady wave resistance or added resistance in head seas. For prediction of total resistance, the use of computed variable wetted areas and wetted lengths in a standard semi-empirical, handbook-type "viscous stripping" algorithm provides a more accurate estimation of viscous drag than is possible otherwise. Results from a variety of IACC and IMS yacht design studies, including comparisons with experimental data, support the conclusion that the free­surface panel code can be used for reliable and accurate prediction of sailboat performance.


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