The Dynamics of Foil Tip Gap Flows
Abstract
Approved for Public ReleaseThe aim of this project is to experimentally investigate the effect of an externally imposed streamwise pressure gradient on tip gap flow and noise. The flows that occur in the gap between a foil tip and an adjacent endwall are complex and their behaviour is influenced by multiple factors including the tip gap height, foil loading, and the character of the boundary layer on the endwall. Although the tip gap flow-field has been well studied in the past, the radiated noise remains poorly understood due to the challenges associated with identifying and quantifying the noise sources and associated flow structures in the gap region between the foil tip and the endwall. This project presents a novel exploration of the mechanics of noise production from tip gapflows subject to endwall pressure gradients. It will build upon UNSW#s recent experimental success in characterizing flow noise production from an idealized tip gap flow created by mounting a foil perpendicular to an endwall upon which a zero-pressure gradient turbulent boundary layer is formed. In this project, the tip gap flow will be exposed to a controllable adverse pressure gradient turbulent boundary layer on the endwall. We will study, for the first time, how the tip gap flow field and the radiated noise varies with endwall pressure gradient flow conditions, tip gap height and foil angle of attack. Measurements of the far-field sound using a microphone array, unsteady surface pressure on the tip and endwall, and flow velocity in the gap region using particle image velocimetry will be obtained along with foil force and vibration data. The extensive flow noise data set obtained in this project will be used to examine how the endwall pressure gradient impacts the unsteady flow structures in the gap, wall pressure field and acoustic emission, providing detailed and novel insight into noise production. It will also be a valuable resource for the validation of computational flow and noise models.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 13, 2023
- Source ID
- N629092312100
Entities
People
- Danielle Moreau
Organizations
- Office of Naval Research
- United States Navy
- University of New South Wales