This study investigates the relations of trapezium channels to roughness coefficient. There are three kinds of coarse materials for using to simulate the surfaces of channel. The hydraulic channel test is performed and the roughness coefficients of coarse materials are estimated. Then, the roughness coefficients of multiple channels are obtained by the hydraulic channel test. Finally, the roughness coefficients of multiple channels are estimated by using the slope-area, area-separation, and wet-perimeter equivalence methods, respectively. These results are compared, and the accuracy of roughness coefficients estimated by three methods is analyzed. The proposed method is provided to estimate effectively the roughness coefficient for the multiple trapezium channels. This method can be useful to promote the safety of hydraulic design in ecological engineering. It provides a convenient and effective method for the hydraulic design of multiple ecological channels. The results show that the effect of slope for the roughness coefficient of multiple trapezium channel is larger than that of flow rate. The roughness coefficients of multiple trapezium channels are I > II > III. The roughness coefficient of multiple trapezium channel obtained by the slope-area method agree with that by the area-separation method. However, the roughness coefficient of multiple trapezium channel obtained by the wet-perimeter equivalence method is different with those obtained by the above two methods.
This study investigates the relations of trapezium channels to roughness coefficient. There are three kinds of coarse materials for using to simulate the surfaces of channel. The hydraulic channel test is performed and the roughness coefficients of coarse materials are estimated. Then, the roughness coefficients of multiple channels are obtained by the hydraulic channel test. Finally, the roughness coefficients of multiple channels are estimated by using the slope-area, area-separation, and wet-perimeter equivalence methods, respectively. These results are compared, and the accuracy of roughness coefficients estimated by three methods is analyzed. The proposed method is provided to estimate effectively the roughness coefficient for the multiple trapezium channels. This method can be useful to promote the safety of hydraulic design in ecological engineering. It provides a convenient and effective method for the hydraulic design of multiple ecological channels. The results show that the effect of slope for the roughness coefficient of multiple trapezium channel is larger than that of flow rate. The roughness coefficients of multiple trapezium channels are I > II > III. The roughness coefficient of multiple trapezium channel obtained by the slope-area method agree with that by the area-separation method. However, the roughness coefficient of multiple trapezium channel obtained by the wet-perimeter equivalence method is different with those obtained by the above two methods.