Question

(fluid mechanics） Open Channels are designed so that water travels at critical flow velocity to allow maximum capacity of the channel, except at flumes where sub-critical flow is used to measure flowrates, etc.

ture or false

Answer 1

True

Open channel is a flow regid with boundary and has upper surface exposed to atmosphere. In open channel flow, the velocity is not constant with depth and the Critical velocity is defined as the speed at which a falling object reaches when both gravity and air resistance are equalised on the object which is a condition of open channel.but the flume is designed in such a way that to measure the flowrates. and in sub critical flow the froude number is less than 1. and in critical flow froude no. is equal to 1. so, by makinf froude no. less than 1. flow rate is find accurately.