6.2 Impact of Internal Waves on Offshore Engineering

Description

The project research activities were designed to provide both a comprehensive understanding and predictive capability of the tidal motions and tidally driven internal wave climatology on the Australian North West Shelf (NWS). This covers the generation, propagation and dissipation of internal waves, and quantitative assessment of the intensity, spatial and temporal distribution of the currents and turbulence induced by these internal waves. The methods involved an integration of field measurements, the development and application of numerical ocean circulation models, and focussed laboratory and theoretical studies.

Field measurement programs were undertaken at physically diverse locations to determine the characteristics of tides and internal waves in the energetic tidally dominated environment of NW Western Australia.

For the first time ever on the Australian North West Shelf, field measurements were made of the rates of ocean mixing due to forcing by the large tides which dominate the oceanography of the North West Shelf. Numerical models were developed, and tested against the field measurements, which were able to both describe and forecast the ocean dynamics throughout the North West Shelf dominated by tides and the internal waves they generate.

Aims

• Understand and quantify the mechanisms of tidally driven internal wave generation, propagation and dissipation at shelf break field sites near North Rankin A, representative of the southern portion of the North West Shelf.
• Understand and quantify the mechanism of tidally driven internal wave generation, propagation and dissipation at field sites near Scott Reef and Browse Basin, representative of the northern portion of the North West Shelf.
• The project aim was to provide a comprehensive understanding and predictive capability of the tidal motions and tidally driven internal wave climatology on the Australian North West Shelf. This covers the generation, propagation and dissipation of internal waves and quantitative assessment of the intensity, spatial and temporal distribution of the currents and turbulence induced by these internal waves.

Reports

Bluteau, C., Jones, N., Ivey, G., & Pattiaratchi, C. (2010). Bottom boundary layer dynamics in an internal wave generation zone. In G. D. Mallinson, & J. E. Cater (Eds.), 17th Australasian Fluid Mechanics Conference (pp. Paper 079). Auckland, New Zealand: University of Auckland.

Bluteau, C., Jones, N., & Ivey, G. (2011). Estimating turbulent kinetic energy dissipation using the inertial subrange method in environmental flows. LIMNOLOGY AND OCEANOGRAPHY-METHODS, 9, 302-321. doi.org/10.4319/lom.2011.9.302

Bluteau, C. E., Jones, N. L., and Ivey, G. N. ( 2011), Dynamics of a tidally‐forced stratified shear flow on the continental slope, J. Geophys. Res., 116, C11017, doi:10.1029/2011JC007214.

Ivey, G. (2011). Tides and Internal Waves on the Continental Shelf. In A. Schiller, & G. B. Brassington (Eds.), Operational Oceanography in the 21st Century (Vol. 1, pp. 225-235). (Operational Oceanography in the 21st Century). Dordrecht: Springer. doi.org/10.1007/978-94-007-0332-2

Lim, K. W., Ivey, G., & Jones, N. (2010). Experiments on the generation of internal waves over continental shelf topography. Journal of Fluid Mechanics, 663, 385-400. doi.org/10.1017/S002211201000354X

Rayson, P., M. Meuleners, G.N. Ivey, N. Jones and G. Wake (2011a) Field and numerical study of the internal tide dynamics in the Browse Basin, Australian North West Shelf. J. Geophys. Res. Oceans, 116: C01016. doi.org/10.1029/2009JC005881

Rayson, M, N. L. Jones, G.N. Ivey and O.B. Fringer (2011b) Internal hydraulic jump formation in a deep water, continuously stratified unsteady channel flow, Proceedings of the Seventh International Symposium on Stratified Flows, Rome, August 2011

Van Gastel, P., G.N. Ivey, M. Meuleners and O. Fringer (2009) The variability of the large-amplitude internal wave field on the Australian North West Shelf. Cont. Shelf Res., 29:1373-1383 doi.org/10.1016/j.csr.2009.02.006