A Measurement of Sound Reflection from a Rib Wall

The sound reflection from periodically uneven surfaces of arbitrary profile has been previously analyzed, and some numerical calculations have been carried out (Ando and Kato [16]).

In this paper, the complex sound reflection coefficient was measured by the “Interference Pattern Method” in a free field which has been developed for an accurate measurement in the near boundary of test materials. Measurements were performed with a glass fiber on a rigid plane and an oblique rib array placed on the glass fiber wall. Tests were made in dependence of the angle of wave incidence. The measured coefficients are compared with the calculated values. Some anomalous phenomena at oblique wave incidence are also discussed.