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Answer this question using your laboratory measurements and the Excel calculations and analysis template corresponding to the Bernoulli equation lab using the Venturi pipe. You're expected to have completed all calculations and plots before attempting this question. 

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In order to convert a pair of volume, V (l), and time T (s) measurements into m3s-1 we need to use the appropriate volume conversion, 1000 l = 1m3, and the fact that Q = V/T.

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Therefore, using example values, V(l)/1000/T(s) = Q (m3s-1) = {V}/1000/{T} = {Q}

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Given that we now know Q (which is constant for the whole system), we can calculate flow velocities at all tapping points using Q (m3s-1) = uA, where u is average flow velocity (ms-1) and A is cross-sectional area (m2). 

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For tapping position E we're given A as 78.5x10-6 m2, therefore: u (ms-1) = Q/A = {Q}/78.5x10-6 = {v_e}

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As shown in the lab material, the theoretical static head at a given tapping position is given by:

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This considers no energy losses throughout the system, therefore static head will be equal to initial total head, HA (m), minus velocity head at this position. Using example data we have:

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Theoretical static head = {h_t}-{v_e}^2/(2*9.81) = {h_theo} (m)

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For advice on parts c) and d) refer to the revealed answers above. 

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Volume (l)

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Time (s)

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Discharge (m3s-1)

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Experimental static head at tapping point A (m)

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Initial total head at tapping point A (m)

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Velocity at the apparatus throat

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Discharge calculations.

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Enter the volume measured at the high flow bench (l): [[0]]

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Enter the average time (s) to fill this volume: [[1]]

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Enter the corresponding flow rate (m3s-1): [[2]]

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Continue using your results for the high-flow bench. 

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What is the experimental static head at tap A, hA(m): [[0]]

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What is the calculated initial total head at tap A, HA(m): [[1]]

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For tapping position E:

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  1. Enter the flow velocity (ms-1): [[2]]
  2. \n
  3. Enter the theoretical static head (m): [[3]]
  4. \n
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Observe the resulting plots and match each curve with its corresponding description:

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Consider the plot showing head loss as a function of discharge. Select the correct option:

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