The Helmholtz Equation Least Squares Method (eBook)

This book represents the HELS (Helmholtz equation least squares) theory and its applications for visualizing acoustic radiation from an arbitrarily shaped vibrating structure in free or confined space. It culminates the most updated research work of the author and his graduate students since 1997. The book contains six chapters. The first serves as a review of the fundamentals in acoustics and the rest cover five specific topics on the HELS theory.

Sean F. Wu received his Ph.D. from Georgia Institute of Technology, U.S.A. in 1987. He joined the Mechanical Engineering Department at Wayne State University as an Assistant Professor in 1988, was promoted to Associate Professor in 1995 and Professor in 1999, was selected in an unanimous vote as the Charles DeVlieg Professor in 2002 and appointed by the Board of Governors to the rank of University Distinguished Professor in 2005.

Dr. Wu holds the rank of Fellow in the American Society of Mechanical Engineers and the Acoustical Society of America, and serves as an Associate Editor and Express Letter Editor for the Journal of the Acoustical Society of America and Co-Editor-In-Chief for Journal of Computational Acoustics.

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This book is written for those who want to learn the state-of-the-art technology on visualizing acoustic radiation from vibrating objects, to understand difficulties involved in these inverse acoustic problems, and to acquire the information necessary to conduct successful vibro-acoustic diagnostics on their own.  Attention is focused on the new development on nearfield acoustical holography (NAH) beyond the traditional Fourier acoustics that are suitable for separable geometries only.  Specifically, it presents:-Helmholtz equation least squares (HELS) method-inverse Helmholtz integral equations implemented via boundary element method- hybrid NAH- and transient NAH that can be employed to tackle various reconstruction of vibro-acoustic fields generated by arbitrary objects subject to arbitrarily time dependent excitations in free or confined space.The new technologies discussed in this book have been used successfully by the author and his research group on visualizing acoustic fields and sound transmission paths into an automobile passenger compartment or through door panels of a sedan and truck.  This book can serve both as a textbook for graduate students and as a reference book for acousticians, researchers, and noise control engineers with basic knowledge of acoustics.  Homework problems are included at the end of each chapter.  In addition, examples of computer programs written in Matlab are provided for the readers' convenience.  This book has been and continues to be designated as the textbook for the graduate level Advanced Acoustics course offered at Wayne State University.