Architectural Engineering


Date of this Version



Hart, C. R. (2014) On a combined adaptive tetrahedral tracing and edge diffraction model, (Doctoral dissertation) University of Nebraska-Lincoln


A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Architectural Engineering, Under the Supervision of Professors Siu-Kit Lau and Lily Wang. Lincoln, Nebraska: May, 2014

Copyright (c) 2014 Carl R. Hart


A major challenge in architectural acoustics is the unification of diffraction models and geometric acoustics. For example, geometric acoustics is insufficient to quantify the scattering characteristics of acoustic diffusors. One method of quantifying the scattering characteristics of acoustic diffusers is through computational prediction, typically via the time-independent boundary element method (BEM). In contrast, time-domain computations are of interest for characterizing both the spatial and temporal scattering characteristics of acoustic diffusors. Hence, a method is sought that predicts acoustic scattering in the time-domain. A prediction method, which combines an advanced image source method and an edge diffraction model, is investigated for the prediction of time-domain scattering. Evaluation of the prediction technique involves numerical verification and numerical validation. Numerical verification is based upon a comparison with analytic and numerical (BEM) solutions for scattering geometries. Good agreement is shown for the selected scattering geometries. Numerical validation is based upon experimentally determined scattered impulse responses of acoustic diffusors. Experimental data suggests that the predictive model is appropriate for high-frequency predictions.

Advisers: Siu-Kit Lau and Lily Wang