Characteristic Variables and Entrainment in 3-D Density Currents

A cfd code has been developed to describe the salt solution density current, which propagatesthree-dimensionally in deep ambient water. the height and width of the dense layer are twodominated length scales in a 3-d structure of the density current. in experimental efforts, itis common to measure the height and width of this current via its brightness. although thereare analytical relations to calculate the current height in a two-dimensional flow, these relationscannot be used to identify the width and height of a 3-d density current, due to the existenceof two unknown parameters. in the present model, the height and width of the dense layerare obtained by using the boundary layer concept. also, a comparison is made between depthaveraged and characteristic variables. then, the computed velocity and concentration profilesare compared with the experimental data and the results show good agreement between them. inthis work, the entrainment coefficient was also calculated using depth-averaged parameters andcompared with the experimental data. the result has the same trend as the ellison and turnerexperiments. present results show that the boundary layer concept can be useful in identifyingthe height and width of a 3-d density current.