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Unformatted text preview: (kPa) 0.125 0 1000 720 2.43 1.50 0.125 peak excess density amplitude (kg/m3) 0.00096 SPL (re: 20 Parms) 132.9 characteristic acoustic impedance (rayl) 874.8 peak temperature amplitude increase (K) 0.0542 shock distance (m) 1813.99 time-averaged acoustic intensity (W/m2) 8.93 3 time-averaged energy density (J/m ) 0.02481 force on a totally absorbing surface of 1 cm2 area (N) 2.481 force on a perfectly reflecting surface of 1 cm2 area (N) 4.961 4. For a gas, develop an expression for the ratio of the discontinuity distance Ld to the shock distance D, that is, Ld/D. 5. a) A 20-kHz sonar source produces sound underwater in fresh water (assume B/A = 5 for water and 1.1 atmosphere ambient pressure at the depth of the source at 20C). If fully developed shock wave formation occurs (the discontinuity distance) at a distance of 1 m, then determine the SPL (re: 20 Pa rms) of the source. b) If the sonar source operates at 2 MHz (typically of diagnostic ultrasound frequencies) with the same SPL, then determine the distance that shock formation would occur. 6. Problem 5.1...
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This note was uploaded on 09/19/2009 for the course ECE 473 taught by Professor Obrian during the Fall '08 term at University of Illinois at Urbana–Champaign.
- Fall '08