Surface coating for reduction of aerodynamic noise and vibrations

Abstract

A coating apparatus for the reduction of aerodynamic noise and vibrations. The coating apparatus is configured to include a group of fibrillar structures, wherein each fibrillar structure is configured with a diverging tip so that the coating reduces the size of and shifts downstream, a separation bubble, and modulates large-scale recirculating motion. Each fibrillar structure can be configured as a cylindrical micropillar. The group of fibrillar structures can be configured as a group of uniformly distributed cylindrical micropillars (e.g., one or more micropillar arrays). The surface coating is effective in reducing the separation bubble and displacing the separation bubble downstream. The coating facilitates a reduction in noise (e.g., aerodynamic noise) and vibrations due to the reduction in the size of the separation bubble.

Description

STATEMENT OF GOVERNMENT RIGHTS[0001]The invention described in this patent application was made with Government support under Contract Number NSF / ONR CBET-1512393 awarded by the Office of Naval Research and the National Science Foundation. The Government has certain rights in the invention.TECHNICAL FIELD[0002]Embodiments are related to the field of flow separation in fluid mechanics and devices, systems and techniques for reducing flow separation. Embodiments also relate to surface coatings for reducing the amount of drag produced in turbulent flow. Embodiments further relate to surface coatings that facilitate the reduction of aerodynamic noise and vibrations.BACKGROUND[0003]Flow separation is a fluid mechanic phenomenon that results in increased drag and loading on structures, causing reduced energy efficiency and possibly compromising structural integrity. As an object travels through a fluid, the velocity of the fluid in contact with the object slows down because of the viscosi...

AI Technical Summary

Benefits of technology

The patent describes a surface coating that reduces drag and noise in turbulent flows. The coating includes fibrillar structures that shift the separation point downstream and reduce the size of a separation bubble. The coating can be used under dry or wet conditions and does not increase the production of TKE. It also reduces the area of negative flow and relies on the generation of distributed wall-normal perturbations. Overall, the coating improves the performance of turbulent flow devices and reduces the energy they produce.

Problems solved by technology

Flow separation is a fluid mechanic phenomenon that results in increased drag and loading on structures, causing reduced energy efficiency and possibly compromising structural integrity.

With respect to aerodynamics, the boundary layer profile begins as laminar and transitions to turbulent as the velocity profile thickens—disrupting the smooth flow and producing skin-friction drag.

When the flow reverses, the boundary layer essentially separates from the surface, creating a drag force that requires more energy to overcome and in some cases causes a plane to stall.

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