Comparison between the fin tube of ellipse and fin tube of circle,obtaining the distribution of the flow field and coming to the conclusion that the radiating level of the fin tube of ellipse is prior to that of circle;with the comparison research of a series of nine fin tubes in different ratioes of length and width,and giving the concept of the optimal ratio of length and width.

The article analyzes the optimal drainage and sand-conveying hydraulic section theory under the clearance height condition for the rectangular sectional channels and culverts of the highways, and gives the optimal width-depth ratio design parameter.

The discussion on the hydraulic account for catchment and optimal ratio between highness and width;