초록 ▼

A device for simulating sound produced by certain equipment, for example a rotor-stator arrangement of a turbomachine, or for generation of opposing sound fields for active sound control, including active sound reduction and active sound amplification, comprises flow obstacles (2) provided in a flow

A device for simulating sound produced by certain equipment, for example a rotor-stator arrangement of a turbomachine, or for generation of opposing sound fields for active sound control, including active sound reduction and active sound amplification, comprises flow obstacles (2) provided in a flow duct (1) flown by a fluid at which vortices (5, 6) are shed at a certain frequency depending on the shape and size of the flow obstacles and the velocity of flow. The quantity and spatial arrangement of the flow obstacles is selected such that a periodically spatially and temporally changing pressure field for the excitation of a sound field (8) of a certain modal content is produced by the entirety of the vortices shed. This sound field reacts synchronizingly on the vortex shedding. The resonant circuit so formed, whose vortex shedding frequency is in the range of the resonant frequency of the sound field to be excited, is the sound source.

대표청구항 ▼

What is claimed is: 1. A method for generating sound fields of a specific modal composition; comprising: providing a fluid flow through a flow duct; providing at least one flow obstacle in the flow duct; adjusting a shape and size of the at least one flow obstacle, and a velocity of the fluid flow,

What is claimed is: 1. A method for generating sound fields of a specific modal composition; comprising: providing a fluid flow through a flow duct; providing at least one flow obstacle in the flow duct; adjusting a shape and size of the at least one flow obstacle, and a velocity of the fluid flow, to create and periodically shed vortices at a certain shedding frequency, selecting a quantity and spatial arrangement of the at least one flow obstacle such that an entirety of the shed vortices produces a periodically spatially and temporally changing pressure field for the excitation of a sound field of a certain modal composition which reacts synchronizingly on the vortex shedding, thereby creating a resultant resonant circuit, whose vortex shedding frequency is in a range of a resonant frequency of the sound field to be excited. 2. A method in accordance with claim 1, and including providing several flow obstacles positioned at intervals in at least one cross-sectional plane of the flow duct. 3. A method in accordance with claim 2, and including projecting the flow obstacles out from an inner wall of the flow duct, and profiling them such that periodic shedding of vortices create a vortex path, as well as the respective modal sound field. 4. A method in accordance with claim 3, and including providing the projections with a stay positioned in the fluid flow and supporting at least one vortex shedding portion spaced from the inner wall of the flow duct in the fluid flow, and profiling the stay such that it produces at most, only negligible vortex shedding. 5. A method in accordance with claim 2, and including providing the flow obstacles as cavities formed into an inner wall of the flow duct. 6. A method in accordance with claim 1, wherein the fluid is one of a cold gas and a hot gas. 7. A method in accordance with claim 1, and including using vibration excitation to control a phase relation of vortex shedding at the flow obstacles. 8. A method in accordance with claim 1, and including providing several flow obstacles that are adjustable in several axes. 9. A method in accordance with claim 2, including positioning the several flow obstacles at regular intervals. 10. A method in accordance with claim 2, including positioning the several flow obstacles at irregular intervals. 11. A method in accordance with claim 2, including positioning the several flow obstacles in multiple circumferential planes. 12. A method in accordance with claim 2, including positioning the several flow obstacles in multiple planes in a direction of fluid flow. 13. A method in accordance with claim 3, and including providing the projections with a stay positioned in the fluid flow and supporting a plurality of vortex shedding portions spaced from each other in the fluid flow, and profiling the stay such that it produces at most, only negligible vortex shedding. 14. A method in accordance with claim 4, and including providing that each stay supports a plurality of vortex shedding portions spaced from each other in the fluid flow. 15. A method in accordance with claim 4, including positioning the several flow obstacles at regular intervals. 16. A method in accordance with claim 4, including positioning the several flow obstacles at irregular intervals. 17. A method in accordance with claim 4, including positioning the several flow obstacles in multiple circumferential planes. 18. A method in accordance with claim 1, and including at least one of simulating a sound produced by rotor-stator arrangements of turbomachines, active sound amplification, and creating an opposing sound field for active sound reduction. 19. A method in accordance with claim 1, wherein the fluid is a liquid.