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Miscellaneous Applications of Coanda Effect
Published in Noor A. Ahmed, Coanda Effect, 2019
In shallow coastal waters, the accompanying diffusion processes that take place between the water flows from the sea or rivers heading toward the sea and stationary or moving marine structures lead to changes in flow patterns along the coast. Other hazardous scenarios are created by the presence of features of sandbars by peers, jetties and so forth, particularly when wind and breaking waves push surface water toward the land and form strong currents, such as rip currents that are strong, localized, and narrow. Rip currents move directly away from the shore in a manner similar to a river flowing out to sea. Figure 4.56 shows a diagrammatic representation of a rip current and a warning sign on a beach and what to do when caught in a rip current.
Geomorphic Features Associated with Erosion
Published in Ramesh P. Singh, Darius Bartlett, Natural Hazards, 2018
Niki Evelpidou, Isidoros Kampolis, Anna Karkani
Sea currents owe their formation to waves directed towards the coast. As waves break near the shore, water accumulates there, resulting in the formation of longshore currents or rip currents. The type of current is defined by the morphology of the beach, the angle of the wave impinging on the coast and the underwater morphology (Karymbalis 2010). The energy that currents transfer drifts beach sediments and alters beach morphology. Their energy is generally increased during storm events and accelerates the retreat of a beach. In places of specific morphology, tidal currents enhance coastal erosion, especially if the area covered during high tide is considerable.
Ocean Beaches, Lakes, Quarries, Springs, and Canals
Published in John R. Fletemeyer, Ivonne Schmid, Principles and Practices of Aquatic Law, 2018
Rip currents are not to be confused with rip tides and undertows. The media commonly makes this mistake. Consequently, they incorrectly warn about the presence of rip tides instead of rip currents. Rip currents are strong, usually temporary currents that flow in a direction away from the beach. The classical description of a rip current was made by Kummer (1952). He describes a rip current as having a slender neck terminating offshore in a shape resembling the head of a mushroom. While this description is fairly accurate, rip currents often are shaped differently than the classical description:
Statistical modeling of undertow on a natural beach
Published in Coastal Engineering Journal, 2022
Borribunnangkun Kullachart, Takayuki Suzuki
Rip currents are dangerous to beach visitors, causing thousands of drownings worldwide. Therefore, these currents have received significant attention over the last three decades (e.g. Svendsen 1984; Castelle et al. 2016). However, rip currents are narrow flows occurring in limited areas under high- to moderate-energy wave conditions (e.g. Aagaard and Vinther 2008), whereas undertows are more easily generated even under low-energy waves (e.g. Borribunnangkun and Suzuki 2019), and the cumulative undertow effect can lead to bathymetry change over a wide area (e.g. Roelvink and Stive 1989; Roelvink et al. 2009; Jayaratne, Rahman, and Shibayama 2014; Suzuki et al. 2019). Hence, to properly manage coastal areas and institute public hazard precautions to enhance swimming safety (e.g. Welsh 1976; Leatherman 2012), undertow prediction is needed.
Perceptions of the risk of drowning at surf beaches among New Zealand youth
Published in International Journal of Injury Control and Safety Promotion, 2018
Stacey Willcox-Pidgeon, Bridget Kool, Kevin Moran
Common risk factors leading people to experience difficulties in the surf include swimming at an unpatrolled surf beach or outside of the designated swimming area (Sherker, Williamson, Hatfield, Brander, & Hayen, 2010), being caught in a rip current (Woodward et al., 2015) and large surf conditions (Blay, 2011). A rip current is defined as a channel of water flowing seaward, in the opposite direction to the waves, often characterized by calm patches or breaks in the surf zone (Gensini & Ashely, 2010; Brander & Short, 2000). Swimmers often get ‘caught’ in a rip current unknowingly swimming in the ‘feeder current’ which flows parallel along the beach to the weakest point where the water quickly becomes deep and flows seaward, dissipating when it gets to the back of the waves (Gensini & Ashely, 2010).