Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-23T23:55:07.088Z Has data issue: false hasContentIssue false

Violent breaking wave impacts. Part 2: modelling the effect of air

Published online by Cambridge University Press:  25 November 2009

H. BREDMOSE*
Affiliation:
School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK
D. H. PEREGRINE
Affiliation:
School of Mathematics, University of Bristol, University Walk, Bristol BS8 1TW, UK
G. N. BULLOCK
Affiliation:
School of Engineering, University of Plymouth, Drake Circus, Plymouth PL4 8AA, UK
*
Email address for correspondence: [email protected]

Abstract

When an ocean wave breaks against a steep-fronted breakwater, sea wall or a similar marine structure, its impact on the structure can be very violent. This paper describes the theoretical studies that, together with field and laboratory investigations, have been carried out in order to gain a better understanding of the processes involved. The wave's approach towards a structure is modelled with classical irrotational flow to obtain the different types of impact profiles that may or may not lead to air entrapment. The subsequent impact is modelled with a novel compressible-flow model for a homogeneous mixture of incompressible liquid and ideal gas. This enables a numerical description of both trapped air pockets and the propagation of pressure shock waves through the aerated water. An exact Riemann solver is developed to permit a finite-volume solution to the flow model with smallest possible local error.

The high pressures measured during wave impacts on a breakwater are reproduced and it is shown that trapped air can be compressed to a pressure of several atmospheres. Pressure shock waves, reflected off nearby surfaces such as the seabed, can lead to pressures comparable with those of the impact. Typical examples of pressure-time histories, force and impulse are presented and discussed in terms of their practical implications. The numerical model proposed is relevant for a variety of flows where air effects are important. Further applications, including extended studies of wave impacts, are discussed.

Type
Papers
Copyright
Copyright © Cambridge University Press 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Deceased

Present address: DTU Mechanical Engineering, Niels Koppels Allé, Building 403, DK-2800 Kgs. Lyngby, Denmark

References

REFERENCES

Bagnold, R. A. 1939 Interim report on wave-pressure research. Proc. Inst, Civil Engng 12, 201226.Google Scholar
Bird, P. A. D., Crawford, A. R., Hewson, P. J. & Bullock, G. N. 1998 An instrument for field measurement of wave impact pressures and seawater aeration. Coastal Engng 35, 103122.CrossRefGoogle Scholar
Blackmore, P. A. & Hewson, P. J. 1984 Experiments on full-scale wave impact pressures. Coastal Engng 8, 331346.CrossRefGoogle Scholar
Bredmose, H., Brocchini, M., Peregrine, D. H. & Thais, L. 2003 Experimental and numerical investigation of steep forced water waves. J. Fluid Mech. 490, 217249.CrossRefGoogle Scholar
Bredmose, H. & Bullock, G. N. 2008 Scaling of wave impact pressures in trapped air pockets. In Proc. 23rd Intl Workshop on Water Waves and Floating Bodies. Jeju, Korea.Google Scholar
Bredmose, H., Peregrine, D. H., Bullock, G. N., Obhrai, C., Müller, G. & Wolters, G. 2004 Extreme wave impact pressures and the effect of aeration. In Proc. 19th Intl Workshop on Water Waves and Floating Bodies. Cortona, Italy.Google Scholar
Bullock, G. N., Crawford, A. R., Hewson, P. J., Walkden, M. J. A. & Bird, P. A. D. 2001 The influence of air and scale on wave impact pressures. Coastal Engng 42, 291312.CrossRefGoogle Scholar
Bullock, G., Obhrai, C., Müller, G., Wolters, G., Peregrine, D. H. & Bredmose, H. 2003 Field and laboratory measurements of wave impacts. In Proc. 3rd Coastal Structures Conf. ASCE.Google Scholar
Bullock, G., Obhrai, C., Müller, G., Wolters, G., Peregrine, D. H. & Bredmose, H. 2004 Characteristics and design implications of breaking wave impacts. In Proc. 29th Intl Conf. Coastal Engng. (ed. McKee-Smith, J.), pp. 39663978. ASCE.Google Scholar
Bullock, G. N., Obhrai, C., Peregrine, D. H. & Bredmose, H. 2007 Violent breaking wave impacts. Part I: Results from large scale regular wave tests on vertical and sloping walls. Coastal Engng. 54 (8), 602617.CrossRefGoogle Scholar
Chan, E. S. & Melville, W. K. 1988 Deep-water plunging wave pressures on a vertical plane wall. Proc. Roy. Soc. Lond. A 417, 95131.Google Scholar
Colicchio, G., Colagrossi, A., Lugni, C., Brocchini, M. & Faltinsen, O. M. 2007 Challenges on the numerical investigation of the flip-through. In Proc. 9th Intl Conf. Num. Ship Hydrodyn., pp. 380–394. CD Rom.Google Scholar
Cooker, M. J. & Peregrine, D. H. 1990 Computation of violent wave motion due to waves breaking against a wall. In Proc. of the 22nd Intl Conf. Coastal Engng., pp. 164167. ASCE.Google Scholar
Cooker, M. J. & Peregrine, D. H. 1991 Violent motion as near-breaking waves meet a vertical wall. In Breaking Waves, IUTAM Symp., Sydney 1990 (ed. Banner, M. L. & Grimshaw, R. H. J.), pp. 291297. IUTAM, Springer.Google Scholar
Cooker, M. J. & Peregrine, D. H. 1992 Wave impact pressure and its effect upon bodies lying on the sea bed. Coastal Engng. 18 (3–4), 205229.CrossRefGoogle Scholar
Cooker, M. J., Vidal, C., Dold, J. W. & Peregrine, D. H. 1990 The interaction between a solitary wave and a submerged semicircular cylinder. J. Fluid Mech. 215, 122.CrossRefGoogle Scholar
Courant, R. & Friedrichs, K. O. 1948 Supersonic Flow and Shock Waves. Interscience.Google Scholar
Dold, J. W. 1992 An efficient surface integral algorithm applied to unsteady gravity waves. J. Comput. Phys. 103, 90115.CrossRefGoogle Scholar
Dold, J. W. & Peregrine, D. H. 1986 An efficient boundary-integral method for steep unsteady water waves. In Numer. Meth. for Fluid Dynamics II (ed. Morton, K. W. & Baines, M. J.), pp. 671679. Oxford University Press.Google Scholar
Faltinsen, O. M., Landrini, M. & Greco, M. 2004 Slamming in marine applications. J. Engng Maths. 48, 187271.CrossRefGoogle Scholar
Fenton, J. D. 1988 The numerical solution of steady water wave problems. Computers & Geosciences 14 (3), 357368.CrossRefGoogle Scholar
Gibson, F. W. 1970 Measurement of the effect of air bubbles on the speed of sound in water. J. Acoust. Soc. Am. 48 (5), 11951197.CrossRefGoogle Scholar
Goda, Y. 2000 Random Seas and Design of Maritime Structures. World Scientific.CrossRefGoogle Scholar
Godunov, S. K. 1959 A difference method for numerical calculation of discontinuous solutions of the equations of hydrodynamics. Math. Sbornik. 47, 271306.Google Scholar
Gómez-Gesteira, M. & Dalrymple, R. A. 2004 Using a three-dimensional smoothed particle hydrodynamics method for wave impact on a tall structure. J. Waterway Port Coastal Ocean Engng 131 (2), 6369.CrossRefGoogle Scholar
Greco, M., Colicchio, G. & Faltinsen, O. M. 2007 Shipping of water on a two-dimensional structure. Part 2. J. Fluid Mech. 581, 371399.CrossRefGoogle Scholar
Hattori, M., Arami, A. & Yui, T. 1994 Wave impact pressure on vertical walls under breaking waves of various types. Coastal Engng 22 (1–2), 79114.CrossRefGoogle Scholar
Hirt, C. W. & Nichols, B. D. 1981 Volume of fluid (vof) method for the dynamics of free boundaries. J. Comp. Phys. 39.CrossRefGoogle Scholar
LeVeque, R. J. 2002 Finite Volume Methods for Hyperbolic Problems. Cambridge University Press.CrossRefGoogle Scholar
Lugni, C., Brocchini, M. & Faltinsen, O. M. 2006 Wave loads: The role of flip-through. Phys. Fluids 18 (122101).CrossRefGoogle Scholar
McCabe, Anne 2003 The effect of entrained air on violent water wave impacts. PhD thesis, School of Mathematics, University of Bristol.Google Scholar
Müller, G., Hull, P., Allsop, W., Bruce, T., Cooker, M. & Franco, L. 2002 Wave effects on blockwork structures: Model tests. IAHR J. Hydr. Res. 40 (2), 117124.CrossRefGoogle Scholar
Nielsen, K. B. & Mayer, S. 2004 Numerical prediction of green water incidents. Ocean Engng 31, 363399.CrossRefGoogle Scholar
Oumeraci, H., Klammer, P. & Partenscky, H. W. 1993 Classification of breaking wave loads on vertical structures. J. Waterway Port Coastal Ocean Engng. 119 (4), 381397.CrossRefGoogle Scholar
Oumeraci, H., Kortenhaus, A., Allsop, W., de Groot, M., Crouch, R., Vrijling, H. & Voortman, H. Eds.) 2001 Probabilistic Design Tools for Vertical Breakwaters. Hydraulic Aspects, Ch 2. A. A. Balkema.Google Scholar
Partenscky, H. W. 1988 Dynamic forces due to breaking waves on vertical structures. In Proc. 2nd Intl Symp. Wave Res. Coast. Engng, pp. 207220. University of Hannover, Germany.Google Scholar
Peregrine, D. H. 2003 Water wave impact on walls. Ann. Rev. Fluid Mech. 35, 2343.CrossRefGoogle Scholar
Peregrine, D. H., Bredmose, H., Bullock, G., Obhrai, C., Müller, G. & Wolters, G. 2004 Water wave impact on walls and the role of air. In Proc. 29th Intl Conf. on Coastal Engng, Lisbon 2004, pp. 40054017. ASCE.Google Scholar
Peregrine, D. H., Bredmose, H., Bullock, G. N., Hunt, A. & Obhrai, C. 2006 Water wave impact on walls and the role of air. In Proc. 30th Intl Conf. Coast. Engng, San Diego (ed. Smith, J. M.), pp. 44944506. ASCE.Google Scholar
Peregrine, D. H. & Thais, L. 1996 The effect of entrained air in violent water wave impacts. J. Fluid Mech. 325, 377397.CrossRefGoogle Scholar
Scott, J. C. 1975 The role of salt in white-cap persistence. Deep Sea Res. 22, 653657.Google Scholar
Scott, J. C. 1976 The preparation of water for surface–clean fluid mechanics. J. Fluid Mech. 69, 339351.CrossRefGoogle Scholar
Slauenwhite, D. E. & Johnson, B. D. 1999 Bubble shattering: Differences in bubble formation in fresh water and seawater. J. Geophys. Res. Oceans 104 (C2), 32653275.CrossRefGoogle Scholar
Tanaka, M., Dold, J. W., Lewy, M. & Peregrine, D. H. 1987 Instability and breaking of a solitary wave. J. Fluid Mech. 135, 235248.CrossRefGoogle Scholar
Tanimoto, K. & Takahashi, S. 1994 Design and construction of caisson breakwaters – the Japanese experience. Coastal Engng 22, 5777.CrossRefGoogle Scholar
Walkden, M. J. A., Crawford, A. R., Bullock, G. N., Hewson, P. J. & Bird, P. A. D 1996 Wave impact loading on vertical structures. In Advances in Coastal Structures and Breakwaters (ed. Clifford, J. E.), pp. 273286. Thomas Telford.CrossRefGoogle Scholar
Wemmenhove, R. 2008 Numerical prediction of two-phase flow in offshore environments. PhD thesis, Rijksuniversiteit Groningen, The Netherlands.Google Scholar
Wolters, G., Müller, G., Bullock, G., Obhrai, C., Peregrine, D. H. & Bredmose, H. 2004 Field and large scale model tests of wave impact pressure propagation into cracks. In Proc. 29th Intl Conf. Coast. Engng, pp. 40274039. ASCE.Google Scholar
Wood, D., Peregrine, D. H. & Bruce, T. 2000 Wave impact on a wall using pressure-impulse theory. I: Trapped air. J. Waterway Port Coastal Ocean Engng 126 (4), 182190.CrossRefGoogle Scholar
Zhang, S., Yue, D. K. P. & Tanizawa, K. 1996 Simulation of plunging wave impact on a vertical wall. J. Fluid Mech. 327, 221–54.CrossRefGoogle Scholar

Bredmose et al. supplementary movie

The movie shows wave impacts on a vertical wall from the experiments in the Grosser Wellenkanal (GWK or Large Wave Channel) at the Forschungzentrum Küste (Coastal Research Centre) in Hannover, Germany. The waves are regular waves with an offshore depth of 4.25 m, a period of 8 s and a wave height of 1.35 m. The movie consists of four sections that show

impacts seen in a view facing the vertical wall. Note the sound associated with the impact and how several of the impacts impose strong vibrations in the laboratory.

close-up of impacts at the wall.

impacts seen from behind the wall. The vertical jet forms a sheet of water that shoots up in the air.

impacts seen from outside the building. The hole in the roof was generated by the waves during earlier experiments within the project.

Download Bredmose et al. supplementary movie(Video)
Video 16.6 MB