The results of measuring the sound absorption by acoustic wedges, which were performed in AC 3 and AC 11 reverberation chambers at the Central Aerohydrodynamic Institute (TsAGI), are presented. Wedges of different densities manufactured from superfine basaltic and thin mineral fibers were investigated. The results of tests of these wedges were compared to the sound absorption of wedges of the operating AC 2 anechoic facility at TsAGI. It is shown that basaltic fiber wedges have better sound absorption characteristics than the investigated analogs and can be recommended for facing anechoic facilities under construction.

Theoretical models of the sound-energy transmission through thin-walled structures from nonuniform, convecting pressure-fluctuation fields were validated through experiments. The fields were created with separated flows at forward-facing and backward-facing steps and vibrations and acoustic radiation of the structures were investigated. Thin plates and model fuselage panels were used. The data permit direct comparison with predicted results as well as evaluation of the validity of the prediction-model assumptions. In particular the elastic and inertial properties of the skin but not of the stiffeners need to be taken into account. The experiments support the validity of previously reported theoretical predictions.

No abstract

No abstract

No abstract