Turbulent Flow Induced by Regular and Irregular Waves above a Steep Rock-Armored Slope
Publication: Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 142, Issue 5
Abstract
The turbulent flow induced by regular and irregular waves on a steep rock-armored slope of 1:3 was studied experimentally. The armor layer consisted of two rows of stones with a median weight of 0.925 N. Four cases of incident waves, whose heights satisfied the hydraulic stability criterion for the armor layer, were tested. The measured wave reflection coefficients were in accordance to values in the literature. Flow measurements were performed using an underwater particle image velocimetry (PIV) system to record instantaneous velocity fields in the region seaward of the breaking point on the slope. In all cases, a return current toward deep water developed, and its magnitude was stronger for the regular than the irregular waves. The vertical profile of the current was approximately linear, and it compared well with a semianalytical model in the literature, which was modified for the present application. The generation of turbulence was enhanced mainly by flow separation resulting from the rough geometry of the armor layer and secondarily by local outflow/inflow resulting from the porosity of the armor layer, and it was correlated to ejection and sweep events. For the regular waves, the relative contributions of the streamwise, transverse, and vertical velocity fluctuations to the mean turbulent kinetic energy were 0.44, 0.28, and 0.28, respectively. The behavior of the phase-averaged velocity field for the regular waves demonstrated that the armor layer behaved as a rough impermeable surface rather than a true porous medium because of the small number (two) of rows of stones.
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Acknowledgments
This paper is part of the research project ARISTEIA I-1718, implemented within the framework of the Education and Lifelong Learning program, and cofinanced by the European Union (European Social Fund) and Hellenic Republic funds.
References
Allsop, N. W. H. (1990). “Reflection performance of rock armoured slopes in random waves.” Proc., 22nd Int. Conf. Coastal Eng., Vol. 2, ASCE, Reston, VA, 1460–1472.
Brunone, B., and Tomasicchio, G. R. (1997). “Wave kinematics at steep slopes: Second-order model.” J. Waterway, Port, Coastal, Ocean Eng., 223–232.
Corvaro, S., Seta, E., Mancinelli, A., and Brocchini, M. (2014). “Flow dynamics on a porous medium.” Coastal Eng., 91, 280–298.
Cox, D. T., and Kobayashi, N. (2000). “Identification of intense, intermittent coherent motions under shoaling and breaking waves.” J. Geophys. Res., 105(C6), 14223–14236.
DaVis 8.1 [Computer software]. Göttingen, Germany, LaVision.
Dixen, M., Hatipoglu, F., Sumer B. M., and Fredsøe, J. (2008). “Wave boundary layer over a stone-covered bed.” Coastal Eng., 55(1), 1–20.
Engelund, F., and Fredsøe, J. (1976). “A sediment transport model for straight alluvial channels.” Nord. Hydrol., 7(5), 293–306.
Hsu, T.-J., Sakakiyama, T., and Liu, P. L.-F. (2002). “A numerical model for wave motions and turbulence flows in front of a composite breakwater.” Coastal Eng., 46(1), 25–50.
Huang, Z. C., Hsiao, S. C., Hwung, H. H., and Chang K. A. (2009). “Turbulence and energy dissipations of surf-zone spilling breakers.” Coastal Eng., 56(7), 733–746.
Hughes, S. A., and Fowler, J. E. (1995). “Estimating wave-induced kinematics at sloping structures” J. Waterway, Port, Coastal, Ocean Eng., 209–215.
Kobayashi, N., Cox, D. T., and Wurjanto, A. (1990). “Irregular wave reflection and run-up on rough impermeable slopes.” J. Waterway, Port, Coastal, Ocean Eng., 708–726.
Kobayashi, N., and Greenwald, J. H. (1988). “Waterline oscillation and riprap movement.” J. Waterway, Port, Coastal, Ocean Eng., 281–566.
Kobayashi, N., and Jacobs, B. K. (1985a). “Riprap stability under wave action.” J. Waterway, Port, Coastal, Ocean Eng., 552–566.
Kobayashi, N., and Jacobs, B. K. (1985b). “Stability of armor units on composite slopes.” J. Waterway, Port, Coastal, Ocean Eng., 880–894.
Kobayashi, N., and Otta, A. K. (1987). “Hydraulic stability analysis of armor units.” J. Waterway, Port, Coastal, Ocean Eng., 171–186.
Kobayashi, N., Otta, A. K., and Roy, I. (1987). “Wave reflection and run-up on rough slopes.” J. Waterway, Port, Coastal, Ocean Eng., 282–298.
LaVision. (2011). Product manual, DaVis 8.0 software, LaVision GmbH, Göttingen, Germany.
Mansard, E. P. D., and Funke, E. R. (1980). “The measurement of incident and reflected spectra using a least squares method.” Proc., 17th Int. Conf. Coastal Eng., ASCE, Reston, VA, 154–172.
Mansard, E. P. D., and Funke, E. R. (1987). “On the reflection analysis of irregular waves.” Technical Rep. TR-HY-017, NRCC No. 27522, National Research Council of Canada, Ottawa, Ontario, Canada.
Nielsen, A. W., Sumer B. M., and Fredsøe, J. (2012). “Suction removal of sediment from between armor blocks. III: Breaking waves.” J. Hydraul. Eng., 803–811.
Putrevu, U., and Svendsen, I. A. (1993). “Vertical structure of the undertow outside the surf zone.” J. Geophys. Res., 98(C12), 22707–22716.
Sakakiyama, T., and Liu, P. L.-F. (2001). “Laboratory experiments for wave motions and turbulence flows in front of a breakwater.” Coastal Eng., 44(2), 117–139.
Svendsen, I. A. (1987). “Analysis of surf zone turbulence.” J. Geophys. Res., 92(C5), 5115–5124.
Ting, F. C. K. (2001). “Laboratory study of wave and turbulence velocities in a broad-banded irregular wave surf zone.” Coastal Eng., 43(3–4), 183–208.
Ting, F. C. K. (2002). “Laboratory study of wave and turbulence characteristics in narrow-band irregular breaking waves.” Coastal Eng., 46(4), 291–313.
Ting, F. C. K., and Kirby, J. T. (1994). “Observation of undertow and turbulence in a laboratory surf zone.” Coastal Eng., 24(1–2), 51–80.
Ting, F. C. K., and Kirby, J. T. (1995). “Dynamics of surf-zone turbulence in a strong plunging breaker.” Coastal Eng., 24(3–4), 177–204.
Ting, F. C. K., and Kirby, J. T. (1996). “Dynamics of surf-zone turbulence in a spilling breaker.” Coastal Eng., 27(3–4), 131–160.
Ting, F. C. K., and Nelson, J. R. (2011). “Laboratory measurements of large-scale near-bed turbulent flow structures under spilling regular waves.” Coastal Eng., 58(2), 151–172.
USACE (United States Army Corps of Engineers). (2002). “Coastal engineering manual.” Engineer Manual 1110–2-1100, Washington, DC.
Wave Synthesizer [Computer software]. Hørsholm, Denmark DHI Water & Environment.
Wurjanto, A., and Kobayashi, N. (1993). “Irregular wave reflection and run-up on permeable slopes.” J. Waterway, Port, Coastal, Ocean Eng., 537–557.
Zelt, J. A., and Skjelbreia, J. E. (1992). “Estimating incident and reflected wave fields using an arbitrary number of wave gauges.” Proc., 23rd Int. Conf. Coastal Eng., ASCE, Reston, VA, 777–789.
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Journal of Waterway, Port, Coastal, and Ocean Engineering
Volume 142 • Issue 5 • September 2016
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© 2016 American Society of Civil Engineers.
History
Received: Sep 23, 2015
Accepted: Feb 16, 2016
Published online: Mar 23, 2016
Discussion open until: Aug 23, 2016
Published in print: Sep 1, 2016
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