Wave setup

In fluid dynamics, wave setup is the increase in mean water level due to the presence of waves. Similarly, wave setdown is a wave-induced decrease of the mean water level. For short, the whole phenomenon is often denoted as wave setup, including both increase and decrease of mean elevation. This setup is primarily present in and near the coastal surf zone. Besides a spatial variation in the (mean) wave setup, also a variation in time may be present – known as surf beat – causing infragravity wave radiation.