List of top Fluid Mechanics Questions asked in GATE CE

The Rational Method formula for estimating peak runoff is given as \(Q = \frac{CiA}{360}\). For the result \(Q\) to be in cubic meters per second (\(m^3/s\)), what must be the units of rainfall intensity (\(i\)) and catchment area (\(A\))?

Match the Gradually Varied Flow (GVF) profiles on a mild slope (\(M_1, M_2, M_3\)) with the nature of their water surface slope (\(dy/dx\)) relative to the flow direction.

Profile & Nature of Slope (\(dy/dx\)) 
P. \(M_1\) Profile & 1. Positive (Rising Curve) 
Q. \(M_2\) Profile & 2. Negative (Drawdown Curve) 
R. \(M_3\) Profile & 3. Positive (Rising Curve) 

Select the correct classification: 

A hydraulic jump occurs in an open channel when the slope of the channel changes from ___________.
 

Consider flow in a long and very wide rectangular open channel. Width of the channel can be considered as infinity compared to the depth of flow. Uniform flow depth is 1.0 m. The bed slope of the channel is 0.0001. The Manning roughness coefficient value is 0.02. Acceleration due to gravity, \( g \), can be taken as 9.81 m/s\(^2\).
The critical depth (in m) corresponding to the flow rate resulting from the above conditions is ________ (round off to one decimal place).
 

In the pin-jointed truss shown in the figure, the members that carry zero force are identified. Which of the following options is/are zero-force members?

When a supercritical stream enters a mild-sloped (M) channel section, the type of flow profile would become 

A jet of water having a velocity of 20 m/s strikes a series of plates fixed radially on a wheel revolving in the same direction as the jet at 15 m/s. What is the percentage efficiency of the plates? (round off to one decimal place)

A very wide rectangular channel carries a discharge $Q=70~\mathrm{m^3/s}$ per meter width. Its bed slope changes from $S_0=0.0001$ to $S_0=0.0009$ at a point $P$ (not to scale). The Manning's roughness coefficient is $n=0.01$. What water-surface profile(s) exist(s) near the point $P$?

A hydraulic jump occurs in a $1.0$ m wide horizontal, frictionless, rectangular channel, with a pre-jump depth of $0.2$ m and a post-jump depth of $1.0$ m. Take $g=10\ \text{m/s^2$. The values of the specific force at the pre-jump and post-jump sections are the same and are equal to (in m$^3$, rounded off to two decimal places).

The pressure in a pipe at X is to be measured by an open manometer as shown in the figure. Fluid A is oil with a specific gravity of 0.8 and Fluid B is mercury with a specific gravity of 13.6. The absolute pressure at X is  kN/m\(^2\). (round off to one decimal place).} 
[Assume Density of water = 1000 kg/m³, gravity = 9.81 m/s², atmospheric pressure = 101.3 kN/m².]

A compound symmetrical open channel section as shown in the figure has a maximum of  critical depth(s).

The critical flow condition in a channel is given by [Note: $\alpha$ – kinetic energy correction factor; $Q$ – discharge; $A_c$ – cross-sectional area of flow at critical flow condition; $T_c$ – top width of flow at critical flow condition; $g$ – acceleration due to gravity]

Which of the following statements is/are TRUE?

The pressure in a pipe at X is to be measured by an open manometer as shown in the figure. Fluid A is oil with a specific gravity of 0.8 and Fluid B is mercury with a specific gravity of 13.6. The absolute pressure at X is  kN/m\(^2\). (round off to one decimal place).} 
[Assume Density of water = 1000 kg/m³, gravity = 9.81 m/s², atmospheric pressure = 101.3 kN/m².]

A hydraulic jump occurs in a 1.0 m wide horizontal, frictionless, rectangular channel, with a pre-jump depth of $0.2$ m and a post-jump depth of $1.0$ m. Take g=10 m/s^2. The values of the specific force at the pre-jump and post-jump sections are the same and are equal to (in m$^3$, rounded off to two decimal places)