CressHelp - A1 - Wind setup

Cress Help - Wind waves and swell - Wave near the shore - Shoaling waters - Wave set-up / set-down - A2.2

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. An empirical equation is derived for irregular waves.

For slopes gentler than 1/10 and wave set-up (for irregular waves, empirical) :

equation 1

and

equation 2

and

equation 3

in which :

Hs = incoming significant wave height [m]

L0p = wave length in deep water [m]

n = wave set up [m]

Tp = peak period [s]

a = angle of slope [°]

x0p = breaker parameter [-]

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.