Calculation of the critical velocity and the critical slope of trailing hydro-transport in open channels

The minimun flow rate which can keep the open channel without siltation is called "the critical velocity".It is significant to the design of trailing hydro-transport.According to the assumption of the minimum energy loss of the muddy water under the critical condition,a formula is obtained by using the differential method in maths.Based on both theory and experiments,the derivation process of this formula is clear and correct.Many factors such as the characteristic parameters of the open channel and the two-phase-flow have been considered,which makes the formula more comprehensive.Meanwhile,it is also in good agreement with the experiment outcome that 94% of the test records are close to the calculation results.So this formula can be applied to multifarious working conditions in trailing hydro-transport projects.In general,this research has solved a special engineering problem successfully and it will be useful to the design of the critical velocity and critical slope of the trailing hydro-transport in open channels.