Jing Yuan, Ole Madsen, Eng Soon Chan


A new oscillatory water tunnel has been built in the Civil and Environmental Engineering Department’s Hydraulic Laboratory at the National University of Singapore. It can accurately produce oscillatory flows that correspond to full-scale sea waves. Tests including pure sinusoidal waves and combined wave-current flows over smooth and rough bottoms have been performed. High quality measurements of the boundary layer flow fields are obtained using a PIV system. The PIV measured flow field is phase and spatially averaged to give a mean vertical velocity profile. It is found that the logarithmic profile can accurately approximate the near-bottom first-harmonic amplitude of sinusoidal waves and give highly accurate determinations of the hydrodynamic roughness and the theoretical bottom location. The bottom shear stress obtained from momentum integral is in general agreement with results from log-profile fitting. The current profiles of combined wave-current flows indicate a two-log-profile structure as suggested by simple combined wave-current flow theory. The difference between the two current shear velocities obtained from combined wave-current flows, as well as a small but meaningful third harmonic embedded in a pure sinusoidal wave, suggest the existence of a time-varying turbulent eddy viscosity.


Oscillatory water tunnel; turbulent wave and wave-current boundary layers; logarithmic profile


Dohmen-Janssen, C. M. and D. M. Hanes. 2002. Sheet flow dynamics under monochromatic nonbreaking waves, J. Geophys. Res., 107(C10), 3149.http://dx.doi.org/10.1029/2001JC001045

Dohmen-Janssen, C. M., W. N. Hassan, et al. 2001. Mobile-bed effects in oscillatory sheet flow, J. Geophys. Res., 106(C11), 27103-27115.http://dx.doi.org/10.1029/2000JC000513

Dohmen-Janssen, C. M., D. F. Kroekenstoel, et al. 2002. Phase lags in oscillatory sheet flow: experiments and bed load modelling, Coastal Engineering, 46(1), 61-87.http://dx.doi.org/10.1016/S0378-3839(02)00056-X

Forristall, G. Z., R. C. Hamilton, et al. 1977. Continental Shelf Currents in Tropical Storm Delia: Observations and Theory, Journal of Physical Oceanography, 7(4), 532-546.http://dx.doi.org/10.1175/1520-0485(1977)007<0532:CSCITS>2.0.CO;2

Grant, W. D. and O. S. Madsen. 1979. Combined Wave and Current Interaction With a Rough Bottom, J. Geophys. Res., 84(C4), 1797-1808.http://dx.doi.org/10.1029/JC084iC04p01797

Hino, M., M. Kashiwayanagi, et al. 1983. Experiments on the turbulence statistics and the structure of a reciprocating oscillatory flow, Journal of Fluid Mechanics, 131, 363-400.http://dx.doi.org/10.1017/S0022112083001378

Jensen, B. L., B. M. Sumer, et al. 1989. Turbulent oscillatory boundary layers at high Reynolds numbers, Journal of Fluid Mechanics, 206, 265-297.http://dx.doi.org/10.1017/S0022112089002302

Jonsson, I. G. 1966. Wave boundary layer and friction factors. the 10th conference on Coastal Engineering, Tokyo, ASCE. 127-148

Jonsson, I. G. and N. A. Carlsen. 1976. Experimental and theoretical investigations in an oscillatory turbulent boundary layer, Journal of Hydraulic Research, 14(1), 45-60.http://dx.doi.org/10.1080/00221687609499687

Madsen, O. S. 1994. Spectral wave-current bottom boundary layer flows. the 24th International Conference on Coastal Engineering, ASCE. 384-398

Nikuradse, J. 1933. Stroemungsgesetze in rauhen Rohren, Ver. Dtsch. Ing. Forsch., 361.

Sleath, J. F. A. 1987. Turbulent oscillatory flow over rough beds, Journal of Fluid Mechanics, 182, 369-409.http://dx.doi.org/10.1017/S0022112087002374

van der A, D. A., T. O'Donoghue, et al. 2011. Experimental study of the turbulent boundary layer in acceleration-skewed oscillatory flow, Journal of Fluid Mechanics, 684, 251-283.http://dx.doi.org/10.1017/jfm.2011.300

Full Text: PDF

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.