Sequential solution of a three-dimensional inverse radiation problem

2003 ◽  
Vol 192 (33-34) ◽  
pp. 3689-3704 ◽  
Author(s):  
H.M. Park ◽  
M.C. Sung
Keyword(s):  
Three Dimensional ◽  
Radiation Problem ◽  
Sequential Solution

Forward-Speed Vertical Wave Exciting Forces on Ships

1985 ◽  
Vol 29 (02) ◽  
pp. 105-111
Author(s):  
P. D. Sclavounos
Keyword(s):  
Velocity Potential ◽  
Reverse Flow ◽  
Diffraction Problem ◽  
Three Dimensional ◽  
Forward Speed ◽  
Direct Solution ◽  
Radiation Problem ◽  
Strip Theory ◽  
Exciting Forces ◽  
Wave Exciting Forces

Expressions are derived for the heave and pitch exciting force and moment on a ship advancing in waves. They are obtained in the form of an integral over the ship axis of the outer source strength of the reverse-flow radiation problem multiplied by the value of the incident-wave velocity potential. Their performance is tested for two slender spheroids. Comparisons are made with predictions obtained from a three-dimensional numerical solution at zero speed—the expression common to strip-theory programs which uses the ship hull as the integration surface—and the direct solution of the diffraction problem.

The absorption of wave energy by a three-dimensional submerged duct

1981 ◽  
Vol 104 ◽  
pp. 189-215 ◽  
Author(s):  
J. R. Thomas
Keyword(s):  
Three Dimensional ◽  
Added Mass ◽  
Axisymmetric Body ◽  
The Body ◽  
Forced Oscillations ◽  
Radiation Problem ◽  
Absorption Length ◽  
Damping Coefficients ◽  
Sea Bed ◽  
Linear Spring

It has been shown (Evans 1976) that the power absorbed by a general, axisymmetric body depends solely upon the added-mass and damping coefficients. These coefficients are fundamental properties of the body, representing the component of the force on the body proportional to the acceleration and velocity of the body respectively in the radiation problem, where the body is forced to oscillate in the absence of incoming waves.In the present paper these coefficients are determined by solution of the radiation problem, for a mouth-upward cylindrical duct situated on the sea bed and fitted with a piston undergoing forced oscillations. The added-mass and damping coefficients are then used to study the power absorption properties of the duct when the power take-off is modelled by a linear-spring–dashpot system attached to the piston. Curves of the added mass, damping coefficients and absorption length (a measure of the power absorbed) as functions of wavenumber are presented, for different duct diameters and different depths of submergence.

Three dimensional numerical modelling for wave radiation problem under arbitrary seabed condition

2021 ◽  
Vol 230 ◽  
pp. 108885
Author(s):  
Aichun Feng ◽  
Ke Chen ◽  
Yunxiang You ◽  
Sheng-Chao Jiang
Keyword(s):  
Numerical Modelling ◽  
Three Dimensional ◽  
Wave Radiation ◽  
Radiation Problem

scholarly journals The heat radiation problem: three-dimensional analysis for arbitrary enclosure geometries

2004 ◽  
Vol 2004 (4) ◽  
pp. 311-330
Author(s):  
Naji Qatanani ◽  
Monika Schulz
Keyword(s):  
Three Dimensional ◽  
Boundary Integral ◽  
Gradient Algorithm ◽  
Heat Radiation ◽  
Banach Fixed Point Theorem ◽  
Discretization Scheme ◽  
Numerical Treatment ◽  
Radiation Problem ◽  
Radiosity Equation ◽  
Uniqueness Of The Solution

This paper gives very significant and up-to-date analytical and numerical results to the three-dimensional heat radiation problem governed by a boundary integral equation. There are two types of enclosure geometries to be considered: convex and nonconvex geometries. The properties of the integral operator of the radiosity equation have been thoroughly investigated and presented. The application of the Banach fixed point theorem proves the existence and the uniqueness of the solution of the radiosity equation. For a nonconvex enclosure geometries, the visibility function must be taken into account. For the numerical treatment of the radiosity equation, we use the boundary element method based on the Galerkin discretization scheme. As a numerical example, we implement the conjugate gradient algorithm with preconditioning to compute the outgoing flux for a three-dimensional nonconvex geometry. This has turned out to be the most efficient method to solve this type of problems.

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