ON BOUNDARY - ELEENT SOLUTIONS OF " WAVE RADIATION - DIFFRACTION PROBLEMS Paul

A distinct feature of wave boundaryintegral equations are the " irregular Two topics on the numerical solution of frequencies. They coincide with the eigenboundary-integral equations arising in linear frequencies of the interior Dirichlet or wave-body interactions are discussed. The Neumann problems, and are known to introduce properties of a spectral technique for the large errors in the predicted hydrodynamic solution of the integral equation are analyzed forces, often over a substantial band of and compared to the conventional collocation frequencies. A comprehensive analysis of the method. It is shown that, using this techmathematical properties of boundaryintegral nique, hydrodynamic forces predicted by the equations, (with emphasis in acoustics), along source-distribution method are identical to with a survey of techniques used for the those obtained from the direct solution for removal of the irregular frequencies, is given the velocity potential. The second part of the in the recent book of Colton and Kreass (1983). paper investigates the numerical properties of The numerical aspects of boundary-integral, as a method which removes the effects of the well as finite-element, hybrid-integral and irregular frequencies for bodies of general finite-element/boundary-integral methods in shape at a small computational and algorithmic free-surface flows are reviewed by Mei (1978), overhead. Its performance is illustrated in Yeung (1982) and Euvrard (1983). the evaluation of the heave and sway hydrodynamic coefficientfi.of a circle and a rectanThe first part of the paper analyzes the gle. ., . . / . properties of a technique for solving bound"ary-integral equations. It is often quoted in