CressHelp - Wind waves and swell - Wave near the shore - Shoaling waters

Cress Help - Wind waves and swell - Wave near the shore - Shoaling waters - Wave set-up / set-down - A2.1

Irregular waves

The wave 'set-up' and ‘set-down' in relation to the SWL (slack-water-line) are calculated with the aid of the linear wave theory for waves approaching at right angles on slopes or bottom slopes with straight parallel depth contours. The relation H/d_b (wave height/depth at which the wave breaks) must be known.

Equations used:

Wave set-down at the breaking point (for regular waves):

equation 1

Maximum wave set-up (for regular waves):

equation 2

With:

equation 3

In which:

db = water depth at location of the breaking point of the waves [m]

Hb = wave height before reaching the breaking point of the waves [m]

nb = wave set-down at the breaking point [m]

g = breaker index [-]

References:

[a] Regelmatige sinusvormige golven, Dictaat B76 "Korte golven deel 2" jan 1986, TU Delft, J.A. Battjes.
[b] Onregelmatige golven, metingen. Gourlay, M.R., Wave set-up, wave run-up and beach water table: Interaction between surf zone hydraulics and groundwater hydraulics, coastal Engineering, vol. 17, 1992.