3D numerical modelling of acoustic horns using the method of fundamental solutions

In the present work, a three-dimensional (3D) formulation based on the method of fundamental solutions (MFS) is applied to the study of acoustic horns. The implemented model follows and extends previous works that only considered two-dimensional and axisymmetric horn configurations. The more realistic case of 3D acoustic horns with symmetry regarding two orthogonal planes is addressed. The use of the domain decomposition technique with two interconnected sub-regions along a continuity boundary is proposed, allowing for the computation of the sound pressure generated by an acoustic horn installed on a rigid screen. In order to reduce the model discretization requirements for these cases, Green’s functions derived with the image source methodology are adopted, automatically accounting for the presence of symmetry conditions. A strategy for the calculation of an optimal position of the virtual sources used by the MFS to define the solution is also used, leading to improved reliability and flexibility of the proposed method. The responses obtained by the developed model are compared to reference solutions, computed by well-established models based on the boundary element method. Additionally, numerically calculated acoustic parameters, such as directivity and beamwidth, are compared with those evaluated experimentally.

On the Analytic Solutions of the Functional Equations w 1 f(a 1 z) + w 2 f(a 2 z) + ... + w n f(a n z) = 0

In this paper, it is showed that, given an integer number n ≥ 2, each zero of an exponential polynomial of the form w1az1+w2az2+⋯+wnazn, with non-null complex numbers w 1,w 2,…,w n and a 1,a 2,…,a n , produces analytic solutions of the functional equation w 1 f(a 1 z) + w 2 f(a 2 z) + ... + w n f(a n z) = 0 on certain domains of C, which represents an extension of some existing results in the literature on this functional equation for the case of positive coefficients a j and w j.

An investigation of the exact solutions of the linearized equations for the flow past conical bodies,

Reproduced from type-written copy.

Error estimation and iterative improvement for the numerical solution of operator equations /

Bibliography: p. 85-87.

Multi-derivative numerical methods for the solution of stiff ordinary differential equations /

"Under contracts US AEC AT(11-1)2383 and US AEC AT(11-1)1469."

1979 SIGNUM Meeting on Numerical Ordinary Differential Equations, April 3-5, 1979, University Inn, Champaign, Illinois : jointly sponsored by Association for Computing Machinery, Special Interest Group on Numerical Mathematics; Department of Computer Science, University of Illinois at Urbana-Champaign; National Science Foundation /

Includes bibliographical references.

An efficient numerical method for highly oscillatory ordinary differential equations /

"Supported in part by the Department of Energy under contract ENERGY/EY-76-S-02-2383, and submitted in partial fulfillment of the requirements of the Graduate College for the degree of doctor of philosophy."

Singular solutions at boundary intersections in two dimensional quasi-linear homogeneous partial differential equations /

Includes bibliographical references (20).

Asymptotic estimation of errors and derivatives for the numerical solution of ordinary differential equations,

"Supported in part by contract US AEC AT(11-1)2383."

Automatic solutions of partial differential equations.

Vita.

A comparison of techniques for the numerical integration of ordinary differential equations,

"COO-1469-0082."

Examination of the solutions of the Navier-Stokes equations for a class of three-dimensional vortices,

"Contract AF 49(638)-255."

Algebraical problems, producing simple and quadratic equations, with their solutions : designed as an introduction to the higher branches of analytics /

Mode of access: Internet.