Experimental study of near-bed concentration and sediment vertical mixing parameter for vertical concentration distribution in the surf zone

Abstract

Two formulae for the near-bed concentration (C¯a) and the sediment vertical mixing parameter (m) are established based on a large scale wave flume experiment. The advantage of the new formulae is that the turbulent kinetic energy induced by wave breaking can be taken into account; the formula for C¯a is in terms of the near-bed, time-averaged turbulent kinetic energy, and the formula for m is in terms of depth- and time-averaged turbulent kinetic energy. A new expression for suspended sediment load also is established by depth integration of the vertical distribution of the suspended sediment concentration obtained on basis of the new formulae. Equation validation is done by comparing the predicted C¯a and m to measurements for different types of waves (regular wave, wave group, and irregular wave), and good agreement is found. The advantages of the proposed formulae over previous formulae also are discussed.