@article{Chvojka_Simard_Amram_1985, title={Study, by reflection, of input impedance under oblique incidence of slotted acoustic screen}, volume={13}, url={https://jcaa.caa-aca.ca/index.php/jcaa/article/view/553}, abstractNote={A new type of phase reversal sound barrier composed of slitted waveguides has shown remarkable noise control properties in low frequency for a plane wave at normal incidence. In order to assess the overall performance (e.g. ground effect, variable source position, etc.) it was necessary to study the effect for obliquely-incident sound wave. Two methods based on reflexion measurements at oblique incidence were applied to study the input impedance of a phase reversal barrier. The first one, successfully used by Klein and Cops (1980), is a stationary wave method derived from that of the impedance tube. The second method presented by Ingard and Bolt (1951), consists of measurements of the complex sound pressure at a point of the sample surface. The results of the study show almost no angular dependence of the system input impedance (locally reacting system within ±40°) in the vertical plane (perpendicular to the slits). On the contrary, in a horizontal plane (parallel to the slits), this angular dependence becomes appreciably stronger}, number={4}, journal={Canadian Acoustics}, author={Chvojka, V.J. and Simard, L.-P. and Amram, M.}, year={1985}, month={Oct.}, pages={25–43} }