title: Measurements of acoustic particle velocity in a coaxial duct and its application to a traveling-wave thermoacoustic heat engine.
abstract: We present theoretical solutions, based on linear acoustic theory, for axial acoustic particle velocity in an annular region of a coaxial duct. The solutions are expressed in terms of two non-dimensional parameters h/δ(ν) and R; h and δ(ν), respectively, represent the half of the spacing between two concentric ducts and the characteristic length given by kinematic viscosity of the gas and angular frequency of acoustic oscillations, and R is the radius ratio of the ducts. The validity of the solutions was verified by direct measurements using a laser Doppler velocimeter. The present results are applied to measurements of the acoustic power distribution in a traveling wave thermoacoustic engine with a coaxial duct, which provides experimental evidence for acoustic power feedback in the coaxial duct.
authors.affiliation: Department of Mechanical Systems and Design, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Morii
authors.affiliation: Department of Mechanical Systems and Design, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Biwa
authors.affiliation: Department of Physics, Aichi University of Education, Kariya 448-8542, Japan.
authors.forename: Taichi
authors.initials: T
authors.lastname: Yazaki