Reduction of Wave Overtopping and Force Impact at Harbor Quays Due to Very Oblique Waves

Abstract

Physical model experiments were conducted in a wave tank at Flanders Hydraulics Research, Antwerp, Belgium, to characterize the wave overtopping and impact force on vertical quay walls and sloping sea dike (1:2.5) under very oblique wave attack (angle between 45° and 80°). This study was triggered by the scarce scientific literature on the overtopping and force reduction due to very oblique waves since large reduction is expected for both when compared with the perpendicular wave attack. The study aimed to compare the results from the experimental tests with formulas derived from previous experiments and applicable to a Belgian harbor generic case. The influence of storm return walls and crest berm width on top of the dikes has been analyzed in combination with the wave obliqueness. The results indicate significant reduction of the overtopping due to very oblique waves and new reduction coefficients were proposed. When compared with formulas from previous studies the proposed coefficients indicate the best fit for the overtopping reduction. Position of the storm return wall respect to the quay edge rather than its height was found to be more important for preventing wave induced overtopping. The force reduction is up to approximately 50% for the oblique waves with respect to the perpendicular wave impact and reduction coefficients were proposed for two different configurations a sea dike and vertical quay wall, respectively.

Non-Hydrostatic Modelling of Coastal Flooding in Port Environments

“…Another example is very oblique wave cases. When the wave directions are very oblique to the structures, even in the extreme case of the primary wave direction being parallel to the structure, the knowledge is limited, excepting some recent studies [4,5]. Dan et al [4] conducted physical model tests in a wave basin to characterise wave overtopping over sloping dikes and quay walls in combination with storm walls under long-crested very oblique waves and associated forces acting on the storm walls.…”

“…When the wave directions are very oblique to the structures, even in the extreme case of the primary wave direction being parallel to the structure, the knowledge is limited, excepting some recent studies [4,5]. Dan et al [4] conducted physical model tests in a wave basin to characterise wave overtopping over sloping dikes and quay walls in combination with storm walls under long-crested very oblique waves and associated forces acting on the storm walls. van Gent [5] investigated the influence of obliqueness on wave overtopping over caisson breakwaters and proposed the gamma factors applicable to vertical structures with and without parapets for short-crested and long-crested waves.…”

“…On top, the applicability of SWASH for the overflow is investigated, as it is an essential application. To this end, relevant physical model tests conducted in the past (Dan et al [4], Willems et al [16]) and empirical formulas are used for the model validation.…”

Wave Interactions with Coastal Structures

“…Dan et al [3] investigated the reduction of wave overtopping and force impact on storm walls on dikes and quays due to very oblique waves, where the wavefront forms an angle of ≥ 45 • with the structure. Such oblique waves need to be assessed when the quay and dike zones inside a harbour are located along the primary wave direction.…”

The influence of berms, roughness and oblique waves on wave overtopping at dikes

“…Additionally, the dikes are often subject to oblique wave attack. These factors can significantly affect the wave overtopping (Juhl and Sloth, 1995;Steendam et al, 2005;Moghim et al, 2015;Eldrup and Lykke Andersen, 2018;Dan et al Schoonees et al, 2021). Hence, the effects of roughness, a berm and oblique waves are subjects of this thesis, the literature on these effects are reviewed in more detail as follows.…”