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Nearfield Acoustical Holography (NAH) has traditionally been utilized in the identification of noise sources on separable geometry of the wave equation. Recent advances have utilized the Boundary Element Method (BEM) to extend the source identification to noise sources with arbitrary geometry. However, this generalized NAH leads to the solution of a discrete ill-posed problem that requires solution through Singular Value Decomposition (SVD) in conjunction with numerical regularization. Robust numerical regularization schemes have recently been implemented in commercial software COMET/Acoustics® [1, 2] so as to fully automate the noise source identification procedure, and render it applicable to complex, practical problems. An application involving noise source identification on the interior of an earthmoving equipment cab is presented to demonstrate the capability of generalized NAH. The NAH reconstructed velocities on the surface of the cab are compared with the input velocities.

Nearfield Acoustical Holography (NAH) has traditionally been utilized in the identification of noise sources on planar structures. The planar NAH was subsequently extended to handle noise source identification on separable geometry such as cylindrical and spherical surfaces using measurements taken on a conforming surface. Recent advances have replaced the mathematics of separable wave propagation with a Boundary Element Method (BEM) based numerical formulation, enabling NAH to reconstruct sources on arbitrarily complex geometry with arbitrarily shaped measurement surfaces. However, this generalized NAH leads to the solution of a discrete ill-posed problem that requires solution through singular value decomposition (SVD) or iterative strategies. Various regularization schemes have been proposed in the literature of inverse problems to be used in conjunction with SVD for robust inversion. Applications of these schemes to generalized NAH problems are beginning to appear in literature.