Title

Computational Modeling of Focused Sonic Booms

Presenter Information

Christopher Pearce
Richard Grist

Document Type

Oral Presentation

Location

SURC Ballroom C/D

Start Date

15-5-2014

End Date

15-5-2014

Keywords

Sonic Boom, Computational, Nonlinear

Abstract

When a supersonic aircraft undergoes a maneuver, such as acceleration, the sonic boom it produces can undergo focusing, producing a 'superboom' to observers on the ground. This focusing is similar to what happens to light after passing through a lens. The studying of superbooms in relation to aircraft shape has the potential to allow supersonic commercial flight over land in the future. While studying these super booms, an analytical approach is not plausible, because nonlinearity and diffraction in sound propagation make the equations too complicated. We use a computational approach to model the sonic boom focusing, allowing us to predict features of the super boom. This research project involved modifying physical and computational parameters of a nonlinear progressive wave equation (NPE) in an attempt to improve the model's accuracy. These initial parameters include: time steps, grid spacing, initial magnitude, and character duration of the incoming boom. The goal is to match computational results to waveforms of actual super booms recorded during NASA flight tests of F-18B aircraft. Our findings show that increasing the number of time steps and creating a finer grid mesh improved agreement on the maximum pressure, but not on other features of the waveform. Modifying physical parameters of the initial wave did not have an appreciable effect on the resulting superboom waveform.

Poster Number

8

Faculty Mentor(s)

Piacsek, Andrew

Additional Mentoring Department

Physics

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May 15th, 8:30 AM May 15th, 11:00 AM

Computational Modeling of Focused Sonic Booms

SURC Ballroom C/D

When a supersonic aircraft undergoes a maneuver, such as acceleration, the sonic boom it produces can undergo focusing, producing a 'superboom' to observers on the ground. This focusing is similar to what happens to light after passing through a lens. The studying of superbooms in relation to aircraft shape has the potential to allow supersonic commercial flight over land in the future. While studying these super booms, an analytical approach is not plausible, because nonlinearity and diffraction in sound propagation make the equations too complicated. We use a computational approach to model the sonic boom focusing, allowing us to predict features of the super boom. This research project involved modifying physical and computational parameters of a nonlinear progressive wave equation (NPE) in an attempt to improve the model's accuracy. These initial parameters include: time steps, grid spacing, initial magnitude, and character duration of the incoming boom. The goal is to match computational results to waveforms of actual super booms recorded during NASA flight tests of F-18B aircraft. Our findings show that increasing the number of time steps and creating a finer grid mesh improved agreement on the maximum pressure, but not on other features of the waveform. Modifying physical parameters of the initial wave did not have an appreciable effect on the resulting superboom waveform.