Shoaling

Shoaling when deep water waves enter a shallow water area

As Shoaling (English spoken [ ʃəʊlɪŋ ]) or Shoaling effect is in the Coastal Engineering the simultaneous reduction of the wavelength and increasing the wave height referred to, which is observed when entering a deep water wave in a shallow water offshore.

If a deep water wave runs into a shallow water area and the wave touches the bottom of the water, the wave speed and thus the wavelength is reduced. For reasons of energy conservation , the reduced kinetic energy must be converted into potential energy (positional energy), which becomes visible through an increased wave height. The shoaling effect increases with flattening water until the wave breaks .

Mathematical description

The extent of shoaling can be described by the ratio of the wave height in the shallow water area to the wave height in the deep water area and abbreviated by the shoaling factor . Assuming a constant flow of energy , a description of the wave speed in deep water and the group speed is also possible: ${\displaystyle \textstyle H}$ ${\displaystyle \textstyle H_{0}}$ ${\displaystyle \textstyle K_{s}}$ ${\displaystyle \textstyle c_{0}}$ ${\displaystyle \textstyle c_{g}}$

${\displaystyle K_{s}={\frac {H}{H_{0}}}={\sqrt {{\frac {1}{2}}\cdot {\frac {c_{0}}{c_{g}}}}}}$

Individual evidence

1. ↑ Working committee "Bank edging" of the Hafentechnische Gesellschaft e. V. and the German Society for Geotechnics e. V. (Hrsg.): Recommendations of the working committee "Bank edging": Port and waterways EAU 2012 . John Wiley & Sons, 2013, ISBN 978-3-433-60240-9 , pp. 119 .
2. ↑ Recommendations for the implementation of coastal protection works by the Committee for Coastal Protection Works (EAK 2002, Corrected Edition 2007) . In: Kuratorium for research in coastal engineering (ed.): The coast . No. 65 , 2007, p. 72 ff . ( kfki.de [PDF; 59.0 MB ]).