Numerical investigation of wave radiation by a vertical cylinder using a fully nonlinear HOBEM

A detailed description of a fully nonlinear numerical method for computing wave interaction effects around arbitrary marine structures is presented. The paper highlights application to one specific geometry: A single, fixed vertical truncated cylinder. The fully nonlinear computations are compared with linear and second-order nonlinear results obtained with the perturbation approach, as well as with experiments.

Download Full-text

On the Second-Order Wave Radiation of an Oscillating Vertical Circular Cylinder in Finite-Depth Water

Journal of Ship Research ◽

10.5957/jsr.1996.40.3.224 ◽

1996 ◽

Vol 40 (03) ◽

pp. 224-234

Author(s):

Ömer Gören

Keyword(s):

Circular Cylinder ◽

Surface Condition ◽

Vertical Cylinder ◽

Finite Depth ◽

Second Order ◽

Field Analysis ◽

Wave Number ◽

Wave Radiation ◽

Integral Theorem ◽

Nonhomogeneous Boundary Condition

A vertical circular cylinder which is in periodic oscillatory motion with small amplitudes in finite depth is considered. The usual assumptions necessary for the potential flow stand valid in the present study. A classical perturbation procedure is employed to solve the nonlinear problem through the second-order. According to the solution method presented, the fluid domain is separated into interior and exterior regions in which boundary-value problems (BVP) are decomposed into two BVPs each having one nonhomogeneous boundary condition. A nonhomogeneous second-order free-surface condition is treated by means of a modified form of Weber's integral theorem. Eigenfunction expansions are used for homogeneous solutions. Thus, to conclude the solution, the exterior and interior solutions are then matched on the common boundary. Numerical results are given for a heaving vertical circular cylinder. Wave field analysis around a vertical cylinder shows that the second-order wave pattern is typically dominated by the second-order wave number related to the second-order dispersion relation. The procedure also satisfies the conditions at infinity through the second-order.

Download Full-text

Numerical Analysis of Natural Convective Heat Transfer over a Vertical Cylinder Using External Fins

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.813-814.707 ◽

2015 ◽

Vol 813-814 ◽

pp. 707-712

Author(s):

Anwesha Panigrahi ◽

D.P. Mishra ◽

Deepak Kumar

Keyword(s):

Heat Transfer ◽

Numerical Investigation ◽

Numerical Study ◽

Convection Heat Transfer ◽

Vertical Cylinder ◽

Working Fluid ◽

Natural Convection Heat Transfer ◽

Maximum Heat ◽

Optimum Parameters ◽

Maximum Heat Transfer

The present numerical study deals with the natural convection heat transfer on the surface of a vertical cylinder with external longitudinal fins. The aim of the study was to determine the effects of geometric parameters like fin height, fin number and fin shape on the heat transfer and thus obtain the optimum parameters that will maximize the rate of heat transfer have been discussed. The numerical investigation consists of an aluminium cylinder of length 1m and diameter 0.07m with air as the working fluid. It has been seen from the numerical investigation that the heat transfer increases with fin height. It is also observed that there exists optimum fin number for maximum heat transfer. Keeping the fin number, fin height and volume fixed, it was found that the heat transfer is maximum for rectangular shaped fin.

Download Full-text