An Innovative Approach to Predicting Scour Depth Around Foundations Under Combined Waves and Currents in Large-Scale Tests Based on Small-Scale Tests

This study presents an innovative theoretical approach to predicting the scour depth around a foundation in large-scale model tests based on small-scale model tests under combined waves and currents.In the present approach,the hydrodynamic parameters were designed based on the Froude similitude criteria.To avoid the cohesive behavior,we scaled the sediment size based on the settling velocity similarity,i.e.,the suspended load similarity.Then,a series of different scale model tests was conducted to obtain the scour depth around the pile in combined waves and currents.The fitting formula of scour depth from the small-scale model tests was used to predict the results of large-scale tests.The accuracy of the present approach was validated by comparing the prediction values with experimental data of large-scale tests.Moreover,the correctness and accuracy of the present approach for foundations with complex shapes,e.g.,the tripod foundation,was further checked.The results indicated that the fitting line from small-scale model tests slightly overestimated the experimental data of large-scale model tests,and the errors can be accepted.In general,the present approach was applied to predict the maximum or equilibrium scour depth of the large-scale model tests around single piles and tripods.

HYDRAULIC SIMILARITY CALCULATION IN MODEL OF SEPARATION OF LIQUID AND SOLID PARTICLES BY WATER INTAKE HEAD WITH INCLINED BOARDINGS

The water intake head installed with inclined boardings is called laminate sediment precipitation, which separates liquid and solid particles in two-phase flow by gravity. The paper presents the equations for calculating the distance H between two incllined boardings, indicating that H has a key effect on the particle precipitation velocity V_2. The paper focuses also on the cal- culation of hydraulic similarity of model with the theoretic model.