Experiments on full-scale wave impact pressures

Blackmore, Paul; Hewson, Paul

doi:10.1016/0378-3839(84)90029-2

Cited by 94 publications

(52 citation statements)

References 3 publications

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“…b is within a range of -0.6 to -1, owning to different experimental configurations (Ariyarathne et al, 2012). Also the level of aeration would affect the rising time (e.g., Blackmore and Hewson, 1984;Bullock et al, 2001). Within these studies, the wave impact of Ariyarathne et al (2012) is induced by overtopping flow (green water in their work), which is similar to the current situation.…”

Section: Impact Processessupporting

confidence: 49%

Overtopping Flow Impact on a Vertical Wall on a Dike Crest

Chen

Hofland

Altomare

et al. 2014

Int. Conf. Coastal. Eng.

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In this paper the impact process and mechanism of overtopping flow on a vertical wall on a dike crest are investigated by means of a series of physical model tests. A double-peaked force was recognized in a time series of an overtoping flow. Four stages were summarized for the whole overtopping flow impact process. An empirical relationship between the maximum impact pressure and impact rising time was found. By using the pressure impulse concept, the empirically established constant product of maximum impact pressure and rising time can be used to develop new design formula in the future.

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Section: Impact Processessupporting

confidence: 49%

Overtopping Flow Impact on a Vertical Wall on a Dike Crest

Chen

Hofland

Altomare

et al. 2014

Int. Conf. Coastal. Eng.

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“…9 suggests that wave impingement effects on organisms have been just as inappropriately overlooked. Historically, although coastal engineers have devoted much effort to the study of impact forces (e.g., Miller et al 1974;Blackmore and Hewson 1984;Cooker and Peregrine 1990), intertidal biologists have typically discounted the importance of wave impact for two reasons. First, it has been believed that flows with high fractions of entrained air are less likely to produce large pressure transients, and breaking waves on rocky shores provide excellent examples of white water.…”

Section: Discussionmentioning

confidence: 99%

Biological implications of surf‐zone flow complexity

Gaylord

2000

Limnology & Oceanography

100

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Wave action imposes potentially large hydrodynamic forces on intertidal plants and animals, and can act as a primary agent of disturbance. It has also been proposed that rapid water accelerations produced by breaking waves might constrain the sizes to which intertidal organisms can grow. However, despite the proven ecological importance of surf-zone flows, few actual measurements of forces imposed on plants or animals by waves in nature have been conducted. In this study, real-time wave forces acting on individuals of the rockweed Pelvetia compressa and a sea urchin Strongylocentrotus purpuratus are recorded in the field. These measured forces are compared with values predicted from theory using laboratory-determined shape factors (i.e., drag and added mass coefficients) and simultaneous flow measurements conducted adjacent to the deployed samples. Results demonstrate that models predicting large contributions of force due to water's acceleration are likely inaccurate, most probably because such models fail to account for the small spatial scales of surf-zone accelerations. This likely eliminates any capacity for intertidal hydrodynamic accelerational forces to limit size, contrary to previous conjectures. Data also suggest that wave-induced forces predicted from simple fluid dynamic expressions can, but sometimes do not, reflect accurately the forces applied. Together these findings imply that although traditional hydrodynamic theory may indeed provide a valuable tool for predicting forces imposed on immersed surf-zone organisms, such approaches must be used with caution. Finally, the field recordings suggest that sharp, transient forces arising from the impingement of waves directly on non-submerged organisms may in general impose the most severe loadings experienced by intertidal plants and animals, a possibility that to date has received little attention. The precise consequences of such brief forces depend on the level of flexibility or rigidity of an organism's construction.In intertidal regions of rocky shores, forces imposed by breaking waves may act as one of the dominant mechanisms determining species presence or abundance, plant and animal diversity, and community structure (Lewis 1964;1968;Dayton 1971;Connell 1978;Paine and Levin 1981;Sousa 1984Sousa , 1985Ricketts et al. 1985). However, despite their importance, wave exposure and the magnitudes of imposed hydrodynamic forces have proven difficult to estimate. Most studies that have attempted to evaluate consequences of breaking waves for intertidal organisms have relied on standard fluid-dynamic theory coupled with idealized flow scenarios that may or may not accurately describe effects of the complex and rapidly evolving water motions of the surf zone (e.g., Koehl 1977;1986;Denny et al. 1985;Denny 1987;1995;Carrington 1990; Denny and Gaines 1990;Dudgeon and Johnson 1992;Bell and Denny 1994;Gaylord et al. 1994; Denny and Gaylord 1996;Blanchette 1997). Thus the validity of models designed to predict the severity or 1 Present address: Dept. Ec...

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“…[1][2][3][4][5]) and full-scale experiments (e.g. [6][7][8][9]) have made further contributions to the knowledge of pressures occurring during wave impact and its effects on coastal structures. This is important for improving the design of coastal structures.…”

Section: Introductionmentioning

confidence: 99%

Wave impacts on structures with rectangular geometries: Part 1. Seawalls

Noar

Greenhow

2015

Applied Ocean Research

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a b s t r a c tThis paper considers steep wave impact on seawalls of various geometries. A simple analytical model for the pressure impulse due to a wave of idealized geometry and dynamics is developed and applied to the following geometries: (a) vertical seawall with a berm, (b) vertical seawall with a ditch at its base and (c) vertical seawall with a block missing (damaged condition).The method uses eigenfunction expansions in each of the rectangular regions that satisfy some of the rigid surface conditions and a simplified free-surface condition. Their unknown coefficients are determined from the impact boundary condition, rigid wall conditions and by matching the values and the horizontal derivatives of the solutions in each rectangular region at their mutual boundary. The method yields the pressure impulse throughout the entire region. The overall impulse and moment impulse on the seawall and a simple model for the uprush of the spray jet after the impact are also presented. The effects of different impact regions and different geometries can therefore be quickly estimated and used to show trends in the results. It is shown that berms generally have a beneficial effect on reducing the impulse, moment impulse and uprush, but not the maximum pressure impulse on the seawall, whereas ditches are generally and sometimes strongly detrimental for all effects except uprush. A missing block in the seawall gives an almost constant or linearly decreasing value inside the gap (depending on the boundary condition applied at the rear of the gap being hard or soft respectively); the soft case can affect the pressure impulse on the front face of the seawall, thereby affecting the impulse and moment impulse.

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Experiments on full-scale wave impact pressures

Cited by 94 publications

References 3 publications

Overtopping Flow Impact on a Vertical Wall on a Dike Crest

Overtopping Flow Impact on a Vertical Wall on a Dike Crest

Biological implications of surf‐zone flow complexity

Wave impacts on structures with rectangular geometries: Part 1. Seawalls

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