Dawood Hamad / 1080935 Experimental procedure: procedure: 1- Switch on the hydraulic bench. 2- Adjust the bench supply valve on the hydraulic bench until the level of the water tank is constant. 3- R ecord H0 (mm) (maximum valve). ecord 4- Insert the pitot -tube assembly into the jet of water from the orifice and record the value of Hc (mm). 5- Measure the diameter of the jet dc (mm). 6- Use some weights to measure the mass of the flow rate by applying those weights and measuring the time needed to raise them. 7- R emove the weights from the hanger to empty the weight tank. emove 8- Turn the valve gradually to measure H0 and time. esults and Conclusion: esults R T he main results of the experiment are: 1. Graph: the relationship between the actual discharge and the square root of the elevation of water in t he tank. 2. Cu = 0.983 .
3. Cc = 0.961 4. Cd (theoretical) =0.945 5. Cd (experimental) =0.969 Discussing the results: From the results of table #2 and graph, it is seen that the relationship between the actual discharge and the square root of the elevation of water in the tank is approximately linear with some distortions due to the presence of some experimental errors. By comparing the experimental and theoretical values of the coefficient of í
í
discharge (Cd) it is noticed that the two values ( 0.969 and 0.945 respectively) are close to each other. This implies that the results of the experiment are accepted and accurate. Conclusion:
From the results of the experiment, it can be concluded that t he flow rate across an orifice depends upon several factors: 1- T he
cross sectional area of the orifice. 2- The total head before the orifice.
3- The type of the Orifice. 4- Its sharpness. * Sources of errors in this experiment include: Systematic errors in the used apparatus. Inaccurate measurement of the discharge disc harge time. T he difficulty in reaching steady flow and the continuous change in the values of Ho and Hc means that some readings were approximated and some required taking an average value. í
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ADD
THIS TO THIS SECTION!!!!!!! Graphical results.
Equation of the straight line in the graph is: ^0.5 Q actual = 56964H 0 + 0.017 Omitting the value of the y -intercept: Slope = Cd * ao * (2g) ^0.5 = 56964 ao = r2= *( 6.5)2=1.327*10 -4 m2