What is the main purpose of a notch in fluid mechanics?
Analysis & Theory
Notches are used to measure the flow (discharge) of liquid from a tank or channel.
Which of the following parameters directly affects flow over a notch?
B
Height of water above notch (head)
Analysis & Theory
The head or height of water above the bottom of the notch affects the discharge rate.
What is the general discharge formula for flow over a rectangular notch?
C
Q = (2/3) × Cd × L × √(2g) × H^1.5
Analysis & Theory
The correct discharge formula for a rectangular notch involves H^1.5 and width L.
What is the unit of discharge in SI units?
Analysis & Theory
Discharge is the volume of fluid flowing per unit time, measured in cubic meters per second (m³/s).
What does Cd represent in notch flow formulas?
Analysis & Theory
Cd is the discharge coefficient, accounting for energy losses and non-ideal flow behavior.
In a V-notch, what does the discharge depend on?
Analysis & Theory
Discharge over a V-notch depends on the head (H) and the notch angle (θ).
Which notch is most accurate for small discharges?
Analysis & Theory
V-notches are sensitive to small heads and are therefore better for low discharge measurements.
If the head over a notch doubles, how does the discharge change (approximately)?
C
It increases more than double
Analysis & Theory
Since discharge is proportional to H^1.5 or H^2.5, it increases more than double when head doubles.
Which condition is necessary for accurate notch flow measurement?
D
Horizontal water surface
Analysis & Theory
For accuracy, the nappe should fall freely and not cling to the notch surface.
What happens if the notch is not properly calibrated?
C
It leads to inaccurate discharge measurements
Analysis & Theory
Improper calibration affects the accuracy of discharge measurement.