초록 ▼

An acoustic resonator (20) has a resonator cavity (22) with a resonator port (24) for communicating with an exhaust flow passage (26) conducting acoustic waves therethrough. Adjustable port structure varies acoustic impedance of the port by various combinations including translation to vary area alo

An acoustic resonator (20) has a resonator cavity (22) with a resonator port (24) for communicating with an exhaust flow passage (26) conducting acoustic waves therethrough. Adjustable port structure varies acoustic impedance of the port by various combinations including translation to vary area along an arcuate surface, translation between discrete areas, translation to cumulatively open port area, multiple translation, multiple ports, rotational area change, and rotational length change. Adaptive control may be provided. A combined passive and active acoustic system may also be provided.

대표청구항 ▼

[ We claim:] [1.] An acoustic resonator comprising a resonator cavity having a resonator port for communicating with an exhaust flow passage conducting acoustic waves therethrough, said resonator port defining an acoustic propagation path along a given direction therethrough from said exhaust flow p

[ We claim:] [1.] An acoustic resonator comprising a resonator cavity having a resonator port for communicating with an exhaust flow passage conducting acoustic waves therethrough, said resonator port defining an acoustic propagation path along a given direction therethrough from said exhaust flow passage into said cavity, said port having a length extending parallel to said given direction, said port having an area extending along a plane transverse to said given direction, adjustable port structure varying acoustic impedance of said port by varying of one said length and said area of said port along a movable arcuate surface, wherein said adjustable port structure comprises a pair of arcuate surfaces, including a first arcuate surface movable toward and away from a second arcuate surface, and wherein said first and second arcuate surfaces have different radii of curvature.