Tsunami-induced scour around monopile foundations

Experimental study of tsunami-induced scour around a monopile foundation

“…Furthermore, continuing until equilibrium is reached will reveal whether the authors' physical understanding of the problem is correct. Similar to the suggestion in the numerical study by Larsen et al (2017), the authors argue that the scour process resembles that within a steady current scour, with the equilibrium scour depth tending to the steady current scour depth limit after taking into account the finite wave boundary layer thickness.…”

“…This assertion is likewise consistent with field measurements of Lacy et al (2012). Larsen et al (2017) simulated the tsunami-induced scour at model scale by also approximating the tsunami-induced flow as a time varying current within a CFD approach. They developed a procedure for properly scaling tsunami-induced scour and came up with a practical engineering model for predicting the scour development beneath successive tsunami waves.…”

“…The single wave was chosen in part because a uni-directional velocity signal could be better controlled than an oscillating signal, and in part because it enabled the study of the scour process using a new generic signal. In contrast, Larsen et al (2017) studied the tsunami-induced scour process by utilizing a sinusoidal flow as a generic tsunami sig- nal. Table 1 lists the maximum free stream velocity, the period, the non-dimensional equilibrium scour depth (S e /D), the boundary layer thickness to water depth ratio (δ/h) and the maximum Shields parameter (θ m ).…”

“…This is reasonable if the monopile is standing off-shore and the Froude number is small. The paper also aims to strengthen the link to the practical engineering models developed in the purely numerical studies by Williams and Fuhrman (2016) and Larsen et al (2017). The numerical models employed in these studies have therefore also been used in the present study to simulate the boundary layers and scour process of selected cases.…”

Run-Up, Boundary Layers and Shear Stresses Beneath Shoaling Tsunamis

“…Recently, Williams and Fuhrman (2016) simulated a series of tsunami scale boundary layers, emphasizing that they are simultaneously both current-and wave-like due to their long duration yet unsteady nature. They viewed the tsunami as a time varying current, something that has also been done by Larsen et al (2017) and in studies of tsunami-induced scour around monopile foundations. This approach is valid sufficiently far off-shore, but nearshore, the effects of the free-surface will inevitably become important.While difficult due to the large scales involved, the run-up and inundation can likewise be studied experimentally (Sriram et al 2016).…”