How experimental determination of Hydraulic Coefficient is done??
Experimental Determination of HydraulicCoefficients
Co-efficient of Discharge (Cd)
• The water is allowed to flow through an orifice fittedto a tank under a constant head at H.
• The water is collected in a measuring tank for thetime t.
• The height of water in the measuring tank isobserved and noted.
Qact = 𝐴𝑟𝑒𝑎 𝑜𝑓 𝑡𝑎𝑛𝑘 ∗ 𝐻𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 𝑖𝑛 𝑡ℎ𝑒 𝑡𝑎𝑛𝑘𝑡𝑖𝑚𝑒 𝑜𝑓 𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑖𝑜𝑛
Cd = 𝑄𝑎𝑐𝑡𝑄𝑡ℎ=𝑄𝑎𝑐𝑡𝐴𝑟𝑒𝑎 𝑜𝑓 𝑜𝑟𝑖𝑓𝑖𝑐𝑒 ∗ 2𝑔𝐻
• Suppose C-C represents the vena contracta of the jet of water coming out of the orifice under constant head H.
• Consider a liquid particle is at C-C when time t=0 and it takes the position P along the jet.
Vertical distance = y = ½ gt2 (t=x/V)
y= ½ g (x2/V2 ) ⇒ V = 𝑔𝑥2 2 𝑦 Vth = 2𝑔𝐻