Seite - 1536 - in Book of Full Papers - Symposium Hydro Engineering

In the inlet structure design it is important to proceed to the analysis of flow velocities that are practiced within and upstream the structure. To this end, the ratio of the velocity flow in the control structure and velocity flow upstream the structure must be in a range of 2 to 5. The inlet separation. In order to drain maximum water sometimes no curve is provided to bottom surface of tunnel which is in touch with invert of approach channel. The flow separation may occur in the transition river section with irregular section for the tunnel section, usually circular or horseshoe sections. 3. GEOMETRIC DESIGN Sections usually adopted for tunnels are covered in IS 4880 (Part III, Hydraulic design) -2000[1]. The functional requirements are defined in a broad sense. Design requirements include all hydraulic and geometric, ancillary and environmental, logistics, and maintenance requirements and limitations. 3.1. TUNNEL DIMENSIONS should be decided on the basis of economic studies so as to obtain a most economical section. The following should be taken into account: Discharge passing through the tunnel flowing partial full is given by: 𝑄 = 2 3 𝐵 𝐶 𝑑 √2𝑔 𝐻 2 3 (2) Where Q= Discharge passing through the tunnel in m3/s B= Width of tunnel in m Cd= Coefficient of discharge g= Acceleration due to gravity H= Net head in m Velocity in tunnel, computed by Manning’s equation 1536