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- Roger Waxler
- SIAM Review
- 1991

- Maarten Hornikx, Roger Waxler, Jens Forssén
- The Journal of the Acoustical Society of America
- 2010

An extended Fourier pseudospectral time-domain (PSTD) method is presented to model atmospheric sound propagation by solving the linearized Euler equations. In this method, evaluation of spatial derivatives is based on an eigenfunction expansion. Evaluation on a spatial grid requires only two spatial points per wavelength. Time iteration is done using a… (More)

- R Waxler
- The Journal of the Acoustical Society of America
- 2001

The second-order time-averaged acoustics of a viscous, thermally conducting gas between closely spaced parallel plates is studied. The acoustic disturbance is studied by expanding the equations of fluid dynamics and heat transfer to second order in Mach number. The undisturbed state is allowed to have a nonzero temperature gradient. A set of coupled… (More)

- Roger Waxler, Carrick L Talmadge, Shantharam Dravida, Kenneth E Gilbert
- The Journal of the Acoustical Society of America
- 2006

The near-ground behavior of the low-frequency (100 Hz to 500 Hz) sound field in the nocturnal sound duct is studied theoretically and experimentally. In the first few meters of the atmosphere, narrow-band sound fields are found to have a characteristic vertical structure. The sound field is the superposition of a "surface mode," whose magnitude decreases… (More)

- Jin H Soh, Kenneth E Gilbert, W M Garth Frazier, Carrick L Talmadge, Roger Waxler
- The Journal of the Acoustical Society of America
- 2010

A method is reported for determining ground impedance in long-range propagation experiments by using the definition of impedance directly. The method is envisioned as way of measuring the impedence at multiple locations along the propagation path, using the signals broadcast during the experiment itself. In a short-range (10 m) test, the direct method was… (More)

- Jelle Assink, Roger Waxler, Doru Velea
- The Journal of the Acoustical Society of America
- 2017

The use of modal expansions to solve the problem of atmospheric infrasound propagation is revisited. A different form of the associated modal equation is introduced, valid for wide-angle propagation in atmospheres with high Mach number flow. The modal equation can be formulated as a quadratic eigenvalue problem for which there are simple and efficient… (More)

- Roger Waxler, Kenneth E Gilbert, Carrick Talmadge
- The Journal of the Acoustical Society of America
- 2008

On clear nights, over flat land, a sound duct develops in which sound can carry to great distances. As is the case with all ducted propagation, there is strong dispersion so that a broadband signal undergoes severe distortion as it propagates. The signal received at long ranges from an impulsive source is a wave train, of much greater duration than the… (More)

- Roger Waxler
- The Journal of the Acoustical Society of America
- 2002

The propagation of sound in a stratified downward-refracting atmosphere over a complex impedance plane is studied. The problem is solved by separating the wave equation into vertical and horizontal parts. The vertical part has non-self-adjoint boundary conditions, so that the well-known expansion in orthonormal eigenfunctions cannot be used. Instead, a less… (More)

- Roger Waxler, Jelle Assink, Doru Velea
- The Journal of the Acoustical Society of America
- 2017

The use of expansions in vertical eigenmodes for long range infrasound propagation modeling in the effective sound speed approximation is investigated. The question of convergence of such expansions is related to the maximum elevation angles that are required. Including atmospheric attenuation leads to a non-self-adjoint vertical eigenvalue problem. The use… (More)

- Philip Blom, Roger Waxler
- The Journal of the Acoustical Society of America
- 2017

The acoustic ray tracing relations are extended by the inclusion of auxiliary parameters describing variations in the spatial ray coordinates and eikonal vector due to changes in the initial conditions. Computation of these parameters allows one to define the geometric spreading factor along individual ray paths and assists in identification of caustic… (More)