286) The discharge through a channel of circular section will be maximum when the depth of water is __________ the diameter of the circular channel.

287) When the Mach number is more than 6, the flow is called

288) The discharge through a convergent mouthpiece is __________ the discharge through an internal mouthpiece of the same diameter and head of water.

289) The separation of flow occurs when the hydrodynamic boundary layer thickness is reduced to zero.

290) If the depth of water in an open channel is less than the critical depth, the flow is called