Experiment No. 6 Flow under a Vertical sluice gate
Module leader: Dr Keith Shepherd
Submission Date: Mon 08/10/2012
Flow under a vertical sluice gate: Part A: Free discharge:
Part A: Free discharge
Time for 1 cube of water to pass the channel =47.2s
Part A: Q1: viii)
Theoretical y2 = 0.0262m
Measured y2 = 0.0280±0.001m
Energy discrepancy = 0.0443J
Based on the hydraulic theory velocity=discharge / height, with the same discharge, lower height of stream flows with higher velocity than stream with greater height. The energy equation K.E.=mv22 and E=y+v22g also show Measured y2 contains lower energy, in other words, energy is dissipated by: * Frictional resistance along the hydraulic structure such as channel and air, this results decrease in velocity and increase in the depth of water, therefore energy is dissipated. The size of friction depends on the channel surface, pressure and velocity of water, and also the viscosity of flow material. Although the friction to the hydraulic structure cannot be eliminated completely, but minimised by reducing the coefficient of friction.
Part A: Q2: v)
Compare Fh and Fg; explain any difference – the actual pressure distribution is reduced as the velocity increases (energy conversation).
From the calculation it seen that the ratio of Fg/Fh approaches of one of several depth ratios, which implies that the differences between the actual force on gate can be represented by the hydrostatic force acting on the gate.
Water depths can be measured upstream and downstream of the sluice gate to calculate the hydrostatic pressure force. By measuring the flow rate, the momentum equation can be applied to calculate the horizontal force acting on the sluice gate. The calculated force can be compared to the actual force acting on the sluice gate by using piezometers to measure...