| With the establishment of the great visions in the 20 th National Congress of the Communist Party and the improvement of people’s awareness of ecological and environmental protection,various efforts are working together to promote the continuous improvement of Chinese river ecosystem,and the construction of fishway projects is also appearing more and more in the main and tributaries of Chinese important rivers.Vertical slit fishway is most commonly used in practical engineering,so this paper firstly compares the actual velocity data measured by the physical model with the calculated value obtained by the numerical simulation,the reliability of the selected turbulence modelwas verified.Then,by changing the diversion Angle at the pier head,increasing the orificium and adding the baffle column on the basis of the vertical slit fishway,the three type were named as Type A,Type B and Type C respectively.17 structural types were designed,and the hydraulic characteristics of three different types of vertical slit fishways were analyzed and compared.(1)By changing the diversion Angle at the pier head,setting 4 structural types,and analyze the hydraulic characteristics of each working condition.By calculating the main stream area of different heights,it is concluded that the main stream area of surface is slightly higher than bottom.By analyzing the maximum velocity、its location and turbulent energy,it is concluded that the maximum velocity and turbulent energy of A1 fishway are better.(2)By changing the size and position of the orifice,setting 9 structural types.Then analyze respectively x-y direction and y-z direction water flow patterns of different orifice positions of fishway B,it was concluded that there were two high velocity area in fishway B,among which the main flow area at the vertical joint was greatly affected by the high velocity area between the orifice,and reflux area was squeezed to a small area.The analysis of velocity at different water surface heights,velocity at different orifice sizes and turbulent kinetic energy shows that with the increase of orifice size,the maximum velocity and turbulent kinetic energy at the vertical joint will decrease correspondingly,and the maximum velocity of the middle and bottom flow is more often found in the high flow velocity area between orifices.(3)By adding baffle columns at different positions,setting 4 structural types.The hydraulic characteristics of various types of fishway are analyzed.Through the analysis of water flow pattern,it is concluded that the baffle column has a certain influence on the distribution of the main flow area.By analyzing the maximum velocity,its location and turbulent energy,it is concluded that although the velocity gradient of C2 fishway is larger,the overall velocity and turbulent energy are lower,which can better meet the demand of fish migration.(4)Based on the hydraulic characteristics of each type of fishway,this paper makes a comprehensive analysis from the aspects of fish passing position,the range of the corresponding preferred swimming speed,the size of the corresponding limit swimming speed and the preferred height in water.Finally associate typical fish,by analyzing the applicability of each type of fishway,it is concluded that the applicability of type A fishway is slightly poor,type B fishway can be applied to more fish,and type C fishway has the best applicability,which can meet the demand of more fish. |
