Boundary perturbation methods for high-frequency acoustic scattering: Shallow periodic gratings

David P. Nicholls, Fernando Reitich
2008 Journal of the Acoustical Society of America  
Despite significant recent advances in numerical methodologies for simulating rough-surface acoustic scattering, their applicability has been constrained by the limitations of state-of-the-art computational resources. This has been particularly true in high-frequency applications where the sheer size of the full-wave simulations render them impractical, and engineering processes must therefore rely on asymptotic models ͓e.g., Kirchhoff approximation ͑KA͔͒. However, the demands for high
more » ... can make the latter inappropriate, thus efficient, error-controllable methodologies must be devised. This paper presents a computational strategy that combines the virtues of rigorous solvers ͑error control͒ with those of high-frequency asymptotic models ͑frequency-independent computational costs͒. These methods are based on high-order "boundary perturbations," which display high precision and unparalleled efficiency. This is accomplished by incorporating asymptotic phase information to effect a significant decrease in computational effort, simultaneously retaining the full-wave nature of the approach. The developments of this contribution are constrained to configurations that preclude multiple scattering; it is further explained how the schemes can be made applicable to general scattering scenarios, though implementation details are left for future work. Even for single-scattering configurations, the approach presented here gives significant gains in accuracy when compared to asymptotic theories ͑e.g., KA͒ with modest additional computational cost.
doi:10.1121/1.2897104 pmid:18529172 fatcat:gxotrfg7rjaodpzs5pfmrpz5cy