Question

# A mercury U-tube manometer measures the pressure difference between two pipes A and B both containing water. Given the dimensions shown in Figure Q1(a), find the difference in pressure between

the two pipes A and B. In less than 50 words describe a practical application of a differential manometer in civil engineering.(ii) Water held in a large tank is to be discharged to sea through a2500 m pipeline. The pipeline consists of two sections: 1.2 m diameter pipe first section from the tank of length1000 m, A = 0.04 1.8 m diameter pipe second section to the sea of length1500 m, A = 0.05 where A is the friction factor of the pipe. Assume all fittings and connections are sudden and that the tank is continually topped up with storm water. Also assume that the end of the discharge pipe is fully submerged in the sea. (i)If the difference in water level between the surfaces of the tank water and the sea is 20 m find the flow rate discharged in m³/s. State all assumptions made. (ii)In less than 50 words describe how to calculate whether fluid flow is laminar or turbulent. Water flows through a 50 mm diameter pipe at a rate of 1.5 kg/s.The pipe forks into two branches of 20 mm diameter and 35 mm diameter. The mean velocity in the 20 mm diameter pipe is 1.5 m/s.Find the mass flow rates in the two pipe branches and the mean velocity in the 50 mm diameter and 35 mm diameter pipes.

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