title: The average specific forced radiation wave impedance of a finite rectangular panel.
abstract: The average specific forced radiation wave impedance of a finite rectangular panel is of importance for the prediction of both sound insulation and sound absorption. In 1982, Thomasson published numerical calculations of the average specific forced radiation wave impedance of a square of side length 2e for wave number k in half octave steps of ke from 0.25 to 64. Thomasson's calculations were for the case when the forced bending wave number kb was less than or equal to k. Thomasson also published approximate formulas for values of ke above and below the published results. This paper combines Thomasson's high and low frequency formulas and compares this combined formula with Thomasson's numerical calculations. The real part of the approximate formula is between 0.7 dB higher and -1 dB lower than the numerical calculations. The imaginary part of the approximate formula is between 2.3 dB higher and -2.6 dB lower than the numerical calculations. This paper also gives approximate formulas for the case when kb is greater than or equal to k. The differences are between 0.8 and -1.2 dB for the imaginary part and between 6.2 and -2.4 dB for the real part.
authors.affiliation: School of Applied Sciences, RMIT University, GPO Box 2476V Melbourne, Victoria 3001, Australia.
authors.forename: John L
authors.initials: JL
authors.lastname: Davy
authors.affiliation: School of Applied Sciences, RMIT University, GPO Box 2476V Melbourne, Victoria 3001, Australia.
authors.forename: David J
authors.initials: DJ
authors.lastname: Larner
authors.affiliation: University of Canterbury, Mechanical Engineering, Private Bag 4800, Christchurch 8140, New Zealand.
authors.forename: Robin R
authors.initials: RR
authors.lastname: Wareing
authors.affiliation: University of Canterbury, Mechanical Engineering, Private Bag 4800, Christchurch 8140, New Zealand.
authors.forename: John R
authors.initials: JR
authors.lastname: Pearse