A formula for the effective wavenumber in a dilute random array of identical scatterers in two
dimensions is derived, based on Lax's quasi-crystalline approximation. This formula replaces
a widely-used expression due to Twersky, which is shown to be based on an inappropriate
choice of pair-correlation function.
This pre-print has been submitted, and accepted, to the journal, Journal of the Acoustical Society of America. The definitive version: LINTON, C.M. and MARTIN, P.A., 2005. Multiple scattering by random configurations of circular cylinders: second-order corrections for the effective wavenumber. Journal of the Acoustical Society of America, 117(6), pp.3413-3423 is available online at: http://asa.aip.org/jasa.html.