CAREER: Flow distortions of quiet serrated structures

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

Acoustic noise is an unavoidable byproduct of flows near aerodynamic structures, where noise is amplified by turbulence interactions with solid bodies. Flow-borne sound contributes to environmental noise levels that are targets for national and international aircraft noise regulations. However, noise also constrains the commercial footprints of wind turbines, emergent commercial unmanned air vehicles, and new paradigms for efficient urban air travel. To address this challenge, serrated edge designs have been adopted in engineering practice, which can affect both the noise level and the fluid dynamics. An acoustic understanding of serrations based on their flow physics remains underdeveloped, where the prevailing noise theory cannot reliably predict changes in noise level. The principal aim of this project is to develop new theoretical models for how edge serrations affect their local fluid flow and their acoustic signature. The objectives of the proposed theoretical research program are to: (1) understand via data reduction of noise experiments how serrations distort incoming flow turbulence; (2) model and predict the distortion of flows pertinent to leading edges and trailing edges; and (3) compute the effect of distorted serrations on local unsteady pressures and the radiated noise. The integrated research and education plan aims to furnish a predictive theoretical framework for serration noise generation, which will be coordinated with global research partners for experimental and numerical validation and will provide international research exchange opportunities for graduate students. This project will also include K-12 educational outreach with the DaVinci Science Center (Allentown, PA), as well as integrate undergraduate research involvement through the Lehigh Biosystems Dynamics Summer Institute (in partnership with Northampton Community College). This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.