Moving velocities of precursor soliton generation in two-layer flow

Based on the AfKdV equation of Xu et al.([1]), a theory on the velocities o f the precursor soliton generation in two-layer flow over topography is pre sented in the present paper. Moving velocities of precursor solitons, of th e first zero-crossing of the tailing wavetrain and of the flow behind the t opography are found theoretically. It is shown that for a given topography, when its moving velocities are at the resonant points, we have the followi ng rules: the ratio of the moving velocity of the precursor solitons to tha t of the first zero-crossing of the tailing wavetrain equals -4/3. At the s ame time, the ratio of the width of generating region of the precursor soli tons to that of the depressed water region equals also -4/3. The theoretica l results are examined by means of numerical calculation. The comparison be tween the theoretical and numerical results are found in good agreement. Fo r different stratified parameters of two-layer how, the velocities of the p recursor soliton generation are also predicted in terms of the present theo retical results.