Diffraction loads on multiple vertical cylinders with rectangular cross section by Trefftz-type finite elements

This paper deals with the application of the so-called ‘frameless’ Trefftz-type finite elements to the calculation of the diffraction loads on multiple vertical cylinders with rectangular cross sections. The method is based on the use of a suitably truncated T-complete set of Trefftz functions over individual subdomains linked by means of a least-square procedure. The vertex singularities and the Sommerfeld radiation condition are readily incorporated in the trial functions. The convergence properties are assessed by means of a boundary error norm. In order to show the performance of the approach, the examples of computations for the arrays of four square vertical cylinders are presented.