Numerical Simulation of Parabolic Profile of Longshore Currents

The three-dimensional nearshore currents model well predicted the typical profile of undertow, i.e. the shoreward near-surface currents and the seaward flow below the wave trough level. Meanwhile, the measurements showed that the longshore currents were logarithmically or parabolically distributed over the depth, but the parabolic profile had not been reproduced by the numerical models (Newberger and Allen, 2007b; Uchiyama et al., 2010). However, Chun and Suh (2017) have shown that the wave-current interaction term in the surface wave stress was attributed to the parabolic profile of longshore currents, and then reproduced the profile of longshore currents in DUCK94. In order to see the parabolic profile of longshore currents in other cases, Chun and Suh's (2017) nearshore current model has been applied to Hamilton et al.'s (2001) laboratory experiment in the present study. Then the numerical results were compared with the measurements including the vertical profiles of longshore currents and undertow.