Abstract

Absorbing boundary conditions (ABCs) are required to truncate the computational domain when performing Finite Element Analyses of exterior acoustic problems where physical domain is unbounded. ABC is applied on a fictitious boundary containing the scatterer and ideally allows outgoing waves to leave without non-physical reflections. Preventing artificial reflections is essential to benefit from the accuracy of the numerical method used. Otherwise, ABC acts as a reflective surface, and artificial reflections distort the solution in the entire domain which is not recoverable by any type of refinement. Pseudodifferential ABCs were used to describe the Dirichlet-to-Neumann map which maps known boundary values on the surface of the scatterer to the normal derivative on the boundary. Hence, the radiation conditions are satisfied which require waves strictly propagate outward of the fictitious boundary. In this work, non-uniform rational B-splines (NURBs) were used to accurately describe the two-dimensional computational geometry and the numerical solution. Three terms of the Pseudodifferential map were used to approximate the DtN map. The proposed ABC was compared to other ABCs such as Karp’s Expansion ABC and BGT type ABC in terms of computational cost and accuracy.

Date of publication

Summer 7-7-2026

Document Type

Thesis

Language

english

Persistent identifier

http://hdl.handle.net/10950/5144

Committee members

Tahsin Khajah, Nelson Fumo, Andrew Robbins

Degree

Master of Science in Mechanical Engineering

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