Theory-based Quiz

Using the Stokes' approximation, you were asked to calculate the non-dimensional drag coefficient for a creeping flow around a cylinder (under 2D assumptions). What do you find out?

What is the correct value of Poiseuille number for laminar flows in round pipes?

$1/5^{th}$ model of car is tested in a wind tunnel. For the flow over the test model to be dynamically similar to that of the full-scale car, the wind tunnel velocity for the model must be: [Hint: both the model and full-scale car are being tested in the same wind-tunnel].

Which of the following theorems can be used to transform the governing equations from the Lagrangian framework to the Eulerian framework?

An isothermal incompressible fluid flows through a perfectly insulated coiled tube. To describe the problem, how many unknowns need to be solved for from the system of equations ?

We wish to use CFD to model the air flow around a car. The car is travelling north at a speed of $60$ $mph$. The wind is blowing south with wind speeds of $10$ $mph$. What inlet boundary velocity value should be used?

The force that acts tangential to the surface of a body moving through a fluid is called

To be considered a continuum fluid flow, the value of Knudsen number should be

Consider the manometer shown in the picture. The pressure difference $\Delta p$ is equal to:

An american football is flying horizontally in air. The plot shows the pressure contours of the ball moving from right to left. In which region is the wake located?

In a pitot tube mounted on an aircraft, what is the difference between the total and static pressures inside the total pressure tube?

Which of the following is a non-intrusive (i.e. the measurement process does not disturb the flow) method of measuring temperature?

An altimeter uses _______ to measure altitude.

For a fluid, the relationship between shear stress and velocity gradients is given by _______, where $\tau=$ shear stress, $\mu=$ dynamic viscosity, $u$ is flow velocity, $y$ is the wall normal distance

A static pitot tube is a probe that contains two openings - at the tip and on the side (as shown in the image). The tip and side openings respectively measure the following physical quantities:

What’s an example of a solid behaving like a fluid?

An american football is flying horizontally in air. The plot shows the pressure contours of the ball moving from right to left. Which region has the lowest pressure?

For a fluid flow to be considered a steady flow, it must be:

The sensor connected to the pitot tube on a racing car is sending a record of increasing total pressure values, while the static pressure is constant. This means that the car is

Which of the following is the correct expression for friction factor for laminar flows in round pipes? ($Re_{D}=\frac{\rho \bar{u}D}{\mu}$)

Fluid statics can be used for ______

The surface forces acting on a fluid parcel comprise of?

(Select the two correct answers.)

An airplane is traveling at a Mach Number = $2$. This means the airplane is traveling at the speed which is _______ times the local speed of sound.

Consider the barometer shown in the picture. If the atmospheric pressure decreases, then the height $h$:

In the case of 2D Poiseuille flow in a 2D planar channel, the maximum velocity occurs at:

When comparing with experiments, the validity range of Oseen's approximation for low Reynolds number flows was found to be _____

What is a reasonable simplifying modeling assumption for a water flow through a coiled tube?

In the conservation of mass equation shown below, which of the following terms is always zero under the incompressible flow assumption

$\partial\rho/\partial\ t+\partial(\rho\ u)/\partial\ x+\partial(\rho\ v)/\partial\ y+\partial(\rho\ w)/\partial\ z=0$

The following measurement technique is applicable for measuring velocity :

(Select the two correct answers.)

Which of the following statements are true in the context of an aircraft stall?

(Select the two correct answers.)

The fundamental physical dimensions used in fluid dynamics are:

(Select the three correct answers.)

A system can be considered as an open system when :

(Select the three correct answers.)

Consider the barometer shown in the picture. In order to maintain the same height $h$ for the same atmospheric pressure, on a planet with twice the gravitational acceleration, we could:

When a force is applied to both a solid and fluid, which of the following is true?

Consider an aircraft flying horizontally at an altitude of $8\ km$ with a speed of $250\ m/s$. The lift force is ______ with respect to the direction of motion of the aircraft.

Which of the following equations is the conservation of energy in the Lagrangian framework?

In a vertical circular water pipe $3\ m$ long with constant diameter ($D = 1\ cm$), water is flowing from inlet (bottom) to outlet (top), in a direction opposite to the gravitational force. The static pressure at the inlet is $101\ kPa$ and inlet velocity is $0.001\ m/s$. Assuming water as an incompressible fluid, the static pressure at the outlet:

For a 3D isothermal viscous fluid flow, if compressibility and heat transfer are not considered, which of the following equations can be avoided from solving?

What does the Reynolds Number physically represent?

The peak of Mount Everest is at an altitude of $8.84$ $km$ above sea level. To reach the summit, climbers trek through the Everest base camp, which is at an altitude of $5.4$ $km$ above the sea level. Assuming an isothermal atmosphere (temperature, $T$), what is the ratio of atmospheric pressures at the summit to that of the base camp.

Lift force on a body is influenced by which of the factors?

(Select the three correct answers.)

Brinkman Number is defined as the ratio of

Two different fluids ($A$ and $B$) are flowing through different pipes. The pressure readings from manometers attached near the outlet ends (point $1$) of each pipe is the same. The two fluid velocities (local to point $1$) in each pipe are also equal. If the density of fluid $A$ is four times that of fluid $B$, the total pressure experienced by fluid $B$ is ___________ compared to fluid $A$. (Assume that the hydrostatic term is the same at the outlets)

If the Prandlt number of a fluid is greater than $1$, this means that the thermal diffusion in the fluid is _________ compared to the momentum diffusion.