Dwayne A. Bourgoyne

Using cross correlations of turbulent flow-induced ambient vibrations to estimate the structural impulse response. Application to structural health monitoring

It has been demonstrated theoretically and experimentally that an estimate of the impulse response (or Greens function) between two receivers can be obtained from the cross correlation of diffuse wave fields at these two receivers in various environments and frequency ranges: ultrasonics, civil engineering, underwater acoustics, and seismology. This result provides a means for structural monitoring using ambient structure-borne noise only, without the use of active sources. This paper presents experimental results obtained from flow-induced random vibration data recorded by pairs of accelerometers mounted within a flat plate or hydrofoil in the test section of the U.S. Navys William B. Morgan Large Cavitation Channel. The experiments were conducted at high Reynolds number (Re > 50 million) with the primary excitation source being turbulent boundary layer pressure fluctuations on the upper and lower surfaces of the plate or foil. Identical deterministic time signatures emerge from the noise cross-correlation function computed via robust and simple processing of noise measured on different days by a pair of passive sensors. These time signatures are used to determine and/or monitor the structural response of the test models from a few hundred to a few thousand Hertz.

Vortex shedding from a hydrofoil at high Reynolds number

High Reynolds number ( Re ) wall-bounded turbulent flows occur in many hydro- and aerodynamic applications. However, the limited amount of high- Re experimental data has hampered the development and validation of scaling laws and modelling techniques applicable to such flows. This paper presents measurements of the turbulent flow near the trailing edge of a two-dimensional lifting surface at chord-based Reynolds numbers, Re

Time-averaged flow over a hydrofoil at high Reynolds number

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Hydrofoil near‐wake sound sources at high Reynolds number

, typical of heavy-lift aircraft wings and full-scale ship propellers. The experiments were conducted in the William B. Morgan Large Cavitation Channel at flow speeds from 0.50 to 18.3ms

Structural monitoring from noise cross correlation

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Hydrofoil sound generation at high Reynolds number

with a cambered hydrofoil having a 3.05m span and a 2.13m chord that generated 60 metric tons of lift at the highest flow speed, Re

Experiments on radiated noise and vibration from a lifting surface at high Reynolds numbers

_{C}{\approx}50{\times}10^{6}

Hydrofoil Turbulent Boundary Layer Separation at High Reynolds Numbers

. Flow-field measurements concentrated on the foils near wake and include results from trailing edges having terminating bevel angles of 44

Lifting surface flow, pressure, and vibration at high Reynolds-number

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Upstream Boundary Layer Influence on Lifting Surface Trailing Edge Vortex Shedding at High Reynolds Number

and 56