Variability in estimates of wind stress on the water surface of a small coastal lagoon

Gibbes, Badin, Olfateh, M., Laursen, R., Grinham, A. and Callaghan, D. (2013). Variability in estimates of wind stress on the water surface of a small coastal lagoon. In: Proceedings 16th International Workshop on Physical Processes in Natural Waters (PPNW2013). PPNW2013: 16th International Workshop on Physical Processes in Natural Waters, Surfers Paradise, QLD, Australia, (51-53). 7-11 July, 2013.

Author Gibbes, Badin
Olfateh, M.
Laursen, R.
Grinham, A.
Callaghan, D.
Title of paper Variability in estimates of wind stress on the water surface of a small coastal lagoon
Conference name PPNW2013: 16th International Workshop on Physical Processes in Natural Waters
Conference location Surfers Paradise, QLD, Australia
Conference dates 7-11 July, 2013
Proceedings title Proceedings 16th International Workshop on Physical Processes in Natural Waters (PPNW2013)
Journal name Centre for Infrastructure Engineering and Management Technical Report
Place of Publication Gold Coast, QLD, Australia
Publisher Centre for Infrastructure Engineering and Management
Publication Year 2013
Sub-type Published abstract
Open Access Status
ISSN 1839-292X
2200-8748
Volume CIEM/2013/R09
Start page 51
End page 53
Total pages 3
Language eng
Formatted Abstract/Summary
Introduction Wind forcing is recognised as one of the key drivers for water movements in lakes, lagoons and reservoirs. Many numerical models simulate wind-induced hydrodynamics by approximating air-water boundary shear stress (wind stress τ0 ) using empirical coefficients and wind speed data such that τ0 = ρɑCDU2/10 [M L-1 T-2] where ρɑ [M L-3] is air density, CD [-] (≈ 1.3 × 10-3) is a drag coefficient in the presence of low wind speeds and small wind-waves and U10 [L T-1] is measured wind speed at 10 m above the water surface. The dependence of CD on both wind speed and surface water wave conditions is widely reported but rarely accounted for in numerical simulations. Wind stress can also be estimated assuming a logarithmic velocity profile such that ŪB (z) = u* / κ ln (z/z0) z z where ŪB (z) is mean the wind velocity [L T-1] at elevation z [L] above the air-water boundary, κ [-] (≈ 0.4) is the von Karman constant, z0 [L] is the roughness height and u* [L T-1] is the friction velocity (e.g., Belcher and Hunt, 1998). Friction velocity is generally proportional to the surface water-wave height although much smaller and is often expressed as τ0 = ρɑu*2 [M L-1 T-2] (Monismith and MacIntyre, 2009). Potential variability between these types of estimates are explored using data collected from wind sensors located close to the water surface of a small coastal lake. Motivation for the research was to better understand the indicative range of uncertainty in measurement derived estimates of boundary shear stress when compared with estimates derived from empirical wind speed relationships. Such variability could be adopted in future modelling studies which seek to explore the propagation of this uncertainty through simulation results of surface mixed layer dynamics...
Keyword Limnology
Logarithmic boundary layer
Wave height
Coastal lagoon
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Conference Paper
Collection: School of Civil Engineering Publications
 
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Created: Fri, 07 Mar 2014, 13:22:39 EST by Julie Hunter on behalf of School of Civil Engineering