Cliffs and clapotis
Stories from Physics for 11-14 14-16
Waves reflected from vertical cliff faces can form a standing wave when they interfere with incoming waves in a process called clapotis. Clapotis rarely results in completely destructive interference as energy will be absorbed by shallow sea beds or transferred to waves scattered by an imperfectly perpendicular cliff face. When large waves strike sea walls, clapotis can produce impressive plumes where the incident and reflected waves superimpose – these may also cause substantial erosion to the structure. When waves strike a barrier at an angle, the crests formed by interference may make a diamond-shaped pattern, known as clapotis gaufré.
C. D. Woodroffe, Coasts: Form, Process and Evolution, Cambridge, Cambridge University Press, 2004, p. 174.
A. Chadwick, J. Morfett, & M. Borthwick, Hydraulics in Civil and Environmental Engineering, Fifth Edition, Boca Raton, FL, CRC Press, 2013, p. 255.
R. Silvester, & J. R. C. Hsu, Costal Stabilization, Singapore, World Scientific, 1993 pp. 68-72.