کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
761738 896646 2010 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Low-frequency sound wave parameter measurement in gravels
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مهندسی مکانیک
پیش نمایش صفحه اول مقاله
Low-frequency sound wave parameter measurement in gravels
چکیده انگلیسی

Experiments were performed to measure the various sound-wave propagation parameters of two kinds of gravel, a crushed limestone and a stream-formed “pea gravel”, at frequencies between 25 and 200 Hz. The apparatus was a very large standing-wave tube with an array of microphones along its entire length. Measurements were made with the tube in the vertical position, filled to various depths, with a pressure-doubling barrier at the bottom. Values were determined for wavelength and attenuation in the gravel and for input impedance at the boundary between gravel and air. The basic analysis method was to fit the parameters of a presumed Green’s function representing the standing wave in the tube to the measured sound pressure amplitudes measured by the microphones. This worked well for some frequencies and some depths of gravel. In other cases, various modifications of the method gave more consistent results. For crushed limestone, the estimates of phase velocity and attenuation increased monotonically with frequency, ranging between 150 and 250 m/s and 0.1 and 0.8 Np/m, respectively. For pea gravel, the estimates increased monotonically with frequency, with values between 160 and 205 m/s and 0.4 and 1.1 Np/m, respectively.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Acoustics - Volume 71, Issue 1, January 2010, Pages 45–51
نویسندگان
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