Rohr, Inc.

Robert L Braden

Vijay V Pujar

Teresa Kruckenberg

Sean Tiwari

Ian F Winfield

Hwa-Wan Kwan

A method of generating a pressure wave proximate an airflow surface and altering airflow to promote a localized lowering of skin friction over the airflow surface is described herein. A series of pressure waves may be configured to create a virtual riblet to control turbulent vortices in a boundary layer adjacent to the airflow surface creating a virtual riblet. The pressure waves may be configured to prevent disruption of the flow of air relative to at least one of a step or a gap associated with the airflow surface. The pressure wave generating system may be comprised of at least one of a thermoacoustic material, a piezoelectric material and a semiconductor material, and a microelectric circuit.

Virtual aerodynamic surface systems

Systems and methods for manufacturing laser-perforated nanoreinforced materials are disclosed. A honeycomb core may utilize a perforated top sheet and a microperforated overlay film coupled to the perforated top sheet. The perforated top sheet and/or the microperforated film may include thermally conductive nanomaterials. The perforations in the top sheet and the microperforations in the film may be laser drilled. The nanomaterials may dissipate heat generated by the laser drilling, allowing for increased perforation speeds.

Systems and methods for perforating materials

An acoustic liner may include a core with a plurality of resonator chambers, a perforated top sheet coupled to the core, and a backskin coupled to the core. A thermoacoustic speaker including nanomaterials may be coupled to at least one of the core, the backskin, and the perforated top sheet. A voltage may be applied to the thermoacoustic speaker. The thermoacoustic carbon nanotube speaker may create a dynamic excitation within a resonator chamber in the core. The dynamic excitation may change the liner acoustic impedance to achieve optimum noise attenuation over a wide range of frequencies or engine operating conditions.

Acoustic attenuation with adaptive impedance

A method of manufacturing an acoustic structure is disclosed. An adhesive material and a septum forming material may be deposited on a first honeycomb ribbon. A second honeycomb ribbon may be adhered to the adhesive material and the septum forming material. The first honeycomb ribbon and the second honeycomb ribbon may be expanded to form a honeycomb structure. The septum forming material may stretch or expand to form a septum cap in a cell of the honeycomb structure. The septum forming material may be inherently porous, and/or the septum cap may be cured in order to introduce pores into the septum cap.

Method of manufacturing septum cap

A passive noise attenuation system is described herein. The passive noise attenuation system may comprise an acoustic structure. The acoustic structure may comprise a perforated top sheet and a core accessible via the perforated top sheet. The core may comprise a cell having a plurality of interior walls. The acoustic structure may comprise a back skin. The acoustic structure may comprise an inherently porous material disposed between the top sheet and the back skin, wherein the porous material forms a plane or multiple planes coupled to each interior wall to tangentially subdivide the core.

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San Diego, CA, United States of America

Robert L Braden