Abstract: Stilling basin with abrupt expansion has been commonly applied to hydro-junction of multi-outlet sluice and pump combined with sluice structure. The calculation of sequent water depth is an inevitable problem to be faced with. Due to the complexity of hydraulic jump in abruptly expanding stilling basin, theoretical study of sequent depth is not yet mature and perfect. According to the test data in some articles, the calculation results of sequent depth obtained in some previous researches are compared and analyzed in quantitative terms. Results suggest that the calculated sequent depth is consistent with the actual situation when pressure head is equal to the mean value of upstream supercritical flow depth and sequent depth. Furthermore, a new method for calculating sequent depth is put forward by giving the calculation formula of circumfluent resistance coefficient based on the model of circumfluent resistance. The correctness and availability of the proposed method is also verified.

Key words: abruptly expanding hydraulic jump, side wall reaction forces, sequent depth, water head, circumfluent resistance coefficient