Near Wake Structure of a Lifting Surface at High Reynolds Number
Abstract
The unsteady separated turbulent flow near the trailing edge of a loaded hydrofoil is often a source of hydroacoustic noise. Although intense near wake turbulence may produce noise directly, near-field vortex-induced pressure fluctuations that scatter from the foil and hydrodynamically-forced structural motions may be the dominant hydroacoustic noise sources at low Mach number. This presentation reports experimental results from a series of recent experiments focused on understanding and documenting these phenomena at chord-based Reynolds numbers up to 60 million. The measurements include foil surface static and dynamic pressures, foil vibration, LDV-determined average flow velocities and turbulence quantities, and PIV flow fields in the immediate vicinity of the foil's trailing edge. The experiments are conducted at the US Navy's William B. Morgan Large Cavitation Channel with a two-dimensional test-section-spanning hydrofoil (2.13 m chord, 3.05 m span) at flow speeds from 0.5 to 18.3 m/s. Special interest is focused near the trailing edge of the foil where interaction between the separated suction- and pressure-side boundary layers may produce structured vorticies in the near wake that enhance hydroacoustic noise generation. [Significant assistance provided by NWSC-CD. Sponsored by ONR Code 333]
- Publication:
-
APS Division of Fluid Dynamics Meeting Abstracts
- Pub Date:
- November 2001
- Bibcode:
- 2001APS..DFD.FH001B