The laboratory experiment and numerical simulations of wave-driven longshore currents by random waves on barred beaches with slopes of 1:100 and 1:40 were conducted to investigate the bimodal feature of mean longshore currents,with emphasis on the location and ratio of two peaks of longshore currents.The location and ratio of two peaks are controlled by the sand bar.The influences of wave heights and beach slopes on the longshore currents are discussed.Numerical simulations were also performed to compute the measured velocity profile,with the emphasis on the effect of lateral mixing,bottom friction and surface rollers on numerical results.
