The drop structure will fail as a result of local scoring downstream.This paper discusses the influence of a drop structures' upstream slope to local scour.Empirical equations of the scour hole were developed by l...The drop structure will fail as a result of local scoring downstream.This paper discusses the influence of a drop structures' upstream slope to local scour.Empirical equations of the scour hole were developed by laboratory experiment,theoretical assumptions,and regression analysis.These equations include the maximum scour depth and length during the scouring period,the maximum equilibrium scour depth and length,and the unit width scour rate.The four channel slopes(0%,2%,4%,and 6%) before the drop structure has been included in the analysis.A series of laboratory experiments were conducted to obtain 48 groups of experiments and 419 scour hole profiles during the scouring period.The material used in the scour section is uniform non-cohesive and with a median diameter of d50 = 0.5 mm.The results have been used to develop empirical equations via regression analysis to determine the coefficients of theoretical equations.The high correlation coefficient indicates that the equations developed in this study are suitable for verifying the characteristics of a scour hole at drop structure in the sloped channel.The semi-empirical equation is more accurate than the empirical equation.Compared to a horizontal channel,a sloped channel tends to cause a greater equilibriummaximum scour length,shorter equilibrium maximum scour depth,and faster unit-wide scour rate.展开更多
基金the research support from Ministry of Science and Technology of Chinese Taipei,with the project no.104-2313-B-343-001
文摘The drop structure will fail as a result of local scoring downstream.This paper discusses the influence of a drop structures' upstream slope to local scour.Empirical equations of the scour hole were developed by laboratory experiment,theoretical assumptions,and regression analysis.These equations include the maximum scour depth and length during the scouring period,the maximum equilibrium scour depth and length,and the unit width scour rate.The four channel slopes(0%,2%,4%,and 6%) before the drop structure has been included in the analysis.A series of laboratory experiments were conducted to obtain 48 groups of experiments and 419 scour hole profiles during the scouring period.The material used in the scour section is uniform non-cohesive and with a median diameter of d50 = 0.5 mm.The results have been used to develop empirical equations via regression analysis to determine the coefficients of theoretical equations.The high correlation coefficient indicates that the equations developed in this study are suitable for verifying the characteristics of a scour hole at drop structure in the sloped channel.The semi-empirical equation is more accurate than the empirical equation.Compared to a horizontal channel,a sloped channel tends to cause a greater equilibriummaximum scour length,shorter equilibrium maximum scour depth,and faster unit-wide scour rate.
