Acoustic lens or prism device for sonar apparatus

摘要

The device uses a refractive medium with a sound velocity which differs from the sound propagation velocity in water, provided by a magneto-or electro-rheological fluid used to fill a lens or prism shape, with an applied magnetic or electric field determining the sound velocity . The fluid may be used to fill a number of chambers, together defining the required shape of the lens or prism, with individual selection of the magnetic or electrical field for each chamber.