Experimental study of enhanced backscattering from a highly irregular, acoustic-elastic interface
- Massachusetts Inst. of Technology, Cambridge, MA (United States)
In this study, experimental and numerical statistical models are developed for the scattering of an acoustic P wave which is incident on a highly irregular, random acoustic-elastic interface to determine the general nature of reflected energy. It is then elucidated whether or not enhanced backscattering, already identified numerically for acoustic (SH) and fully elastic media (P-SV), occurs. Experimentally, a glass etching process using photoresist templates with Gaussian statistics allowed for the generation of characterized interface irregularities. Experiments were performed on a glass surface with an `rms` slope of 30 deg, for the case of an incident wavelength with a size on the same order as the interface irregularities. The numerical models predict an enhancement of energy diffracted back toward the source, and results obtained in our ultrasonic laboratory strongly support the presence of this retroreflective energy. In terms of general scattering, it is found that, at smaller incident angles (relative to vertical), the 2-D numerical results can give insight into the 3-D experimentally observed scattering over most scattering angles. However, at larger incident angles, fundamental differences between 2-D and 3-D scattering may exist. 24 refs., 15 figs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 219656
- Journal Information:
- Journal of the Acoustical Society of America, Vol. 99, Issue 2; Other Information: PBD: Feb 1996
- Country of Publication:
- United States
- Language:
- English
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