Nowadays, interest in the problem of nonlinear radiation of airborne sound was accelerated in connection with some new applications concerning directional acoustic beams. Using of the parametric arrays enables to overcome the diffraction limit effectively, it means that it is possible to generate very directional and nearly sidelobe free beams of low frequency sound. Within this project, we plan to focus on problems which are related to modelling of propagation of nonlinear acoustic beams, self-demodulation of low-frequency signals and method of generation of very directional acoustic beams. As model equation we will use the KZK equation which must be solved numerically. To be able to realize experiments for theory verification, we suppose to realize the membrane transducers. For this purpose we will use biaxially stretched PVDF-film. On the basis of acquired experience we will make next parametric arrays to achieve the best possible transmitting parameters. Finally, we will try to use the realized parametric arrays for nondestructive non-contacting testing of solid materials. (en)
Cílem projektu je modelování nelineárních akustických svazků parametrických akustických polí, která dovolují vytvářet nízkofrekvenční velmi směrová zvuková pole. Součástí projektu je návrh a realizace parametrických polí s ohledem na jejich využití pro bezkontaktní nedestruktivní testování materiálů