The main measure of response to aquatic oil spills is the mechanical containment and recovery from the water surface. The majority of containment booms are not effective when the relative current/tow speed exceeds approximately 1 knot. A research study was conducted to assess the performance of some existing booms and to propose improved and novel boom concepts for use in high-speed situations. Studied booms included conventional single-skirt and L-shaped booms, and boom systems involving screens and ramped skirts. The study included two-dimensional computational fluid dynamics simulations and physical modeling experiments. The computational modeling utilized the open-source OpenFOAM toolbox briefly validated prior to computational modeling of high-speed boom concepts. The physical modeling component was conducted in a 95-m-long and 2-m-wide wave-current flume. Despite some differences in the details of what was computationally and physically modeled, the boom performance and containment success were generally consistent. Among several studied boom concepts, ramped-boom and screen-boom systems were most promising for the containment of light and medium oils in relative speeds of 2–3 knots.
Over the past decade, the use of imaging devices to perform quantitative measurements has seen wide-scale adoption and has become integral to the emerging fields of research, such as computer vision and artificial intelligence. Recent studies, published across a wide variety of fields, have demonstrated a vast number of ways through which image-based measurement systems can be used in their respective fields. A growing number of studies have demonstrated applications in coastal and ocean research. Edge detection methods have been used to measure water surface and bedform elevation from recorded video taken during wave flume experiments. The turbulent mixing of air and water, induced by the breaking waves and the runup processes, poses a particular problem for the edge-detection methods, since they rely on a sharp contrast between air and water. In this paper, an alternative method for tracking water surface, based on color segmentation, is presented. A set of experiments were conducted whereby the proposed method was used to detect water surface profiles for various types of breaking waves interacting with a rubble mound breakwater. The results were further processed to compute the surface velocity during runup. The time-history of surface velocity is shown to closely parallel the point measurements taken nearby the instrumented armor unit. These velocities can potentially serve as boundary conditions for determining the dynamic loads exerted on the armour units. Further, the image processing results are used to remove the time-varying buoyant force from the measured force acting on an individual armour unit, providing additional insight into how the forces develop over time.
Anchored Large Woody Debris (LWD) is increasingly being used as one of several nature-based coastal protection strategies along the north-western coasts of Canada and the US. As an alternative to conventional hard armoring (e.g., seawalls), its usage is widely considered to be less harmful to the coastal ecosystem while maintaining the ability to protect the beaches against wave attack and erosion. The effects of seawalls on beaches have been extensively studied; however, the performance and efficacy of LWD and its potential as a suitable alternative to seawalls (and other shoreline protection structures) are still understudied in current research. This paper presents and compares the effects of a conventional vertical seawall with two different LWD structures on beach morphology and wave reflection through large-scale physical modeling in a wave flume at a 1:5 scale. An assessment of techniques used to measure beach morphology and an assessment of model effects were included in the study. It was found that the wave reflection could be reduced by using a single log instead of a wall structure, while changes in the beach morphology response largely depended on the type of the LWD structure. A stacked log wall showed near-identical behavior as a conventional seawall. Visible model effects from the experiments, including the effect of the flume sidewalls on the beach morphology, were quantified and analyzed to inform future research.
1 May 2025 in Journal of Waterway, Port, Coastal, and Ocean Engineering