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Basics of Fluid Dynamics

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The fundamental physical dimensions used in fluid dynamics are:

**(Select the three correct answers.)**

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What part of a fluid parcel do the body forces act on?

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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.

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

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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:

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Which of the following are examples of internal flows?

**(Select the two correct answers.)**

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$1/5^{th}$ 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].

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Strouhal number, $St$, is a non-dimensional representation of frequency, $f$. Select the expression of $St$ using characteristic velocity $V$ and length $L$. The units of frequency is $Hz$ which is inverse of time.

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The mean velocity for an axisymmetric fully developed flow in a round pipe (Axisymmetric Hagen-Poiseuille Flow) is:

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In the case of 2D Poiseuille flow in a 2D planar channel, the velocity profile is:

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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:

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The following measurement technique is applicable for measuring velocity :

(Select the two correct answers.)

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The liquid in a manometer is at the same height on both the tubes. This means that:

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When a fluid is at rest, the total gravitational force exerts a ________ force on any surrounding surfaces as a result of _____________.

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Which of the following is true about Helmholtz Vortex Theorems (about vorticity fields)?

**(Select the three correct answers.)**

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What is the expression of the pressure force component of surface forces in terms of surface integrals?

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The frictional force experienced by a body is the lowest when moving through which one of the following fluids?

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

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

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

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Which fundamental law of physics is the foundation for the energy equation?

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In a horizontal circular water pipe $2\ m$ long, the diameter at the inlet is $1\ cm$ and the inlet velocity is $V = 0.001\ m/s$. Assuming water as an incompressible fluid and if the outlet diameter is $0.5\ cm$, the outlet water velocity:

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What are the terms in the viscous stress tensor dependent on?

**(Select the two correct answers.)**

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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

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Which of the following is a valid modeling assumption?

**(Select the three correct answers.)**

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What is the mathematical classification of equations for a supersonic flow problem?

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Brinkman Number is defined as the ratio of

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What is the definition of the Knudsen number?

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Given basic dimensions of mass $M$, length $L$ and time $T$, what would be dimensions of Viscosity:

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Fluid statics can be used for ______

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Given the fluid velocity field $\overline{V}$, Which of the following is the correct expression for vorticity?

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An aircraft wing is oriented at an angle of attack greater than its design stall condition. To confirm that the wing indeed stalled, which of the following would you check for, with further increase in angle of attack?

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

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What are ALL the components that describe the general motion of a fluid element?

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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.

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Which of the following statements are true regarding the "specific gravity"?

**(Select the two correct answers.)**

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What does the Reynolds Number physically represent?

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In the case of irrotational flows, the circulation along any closed contour is equal to

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

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In the case of Couette flow between two moving plates, the velocity profile is:

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Consider steady laminar axisymmetric flow of a viscous fluid between two long concentric cylinders where the inner cylinder of radius $R_{i}$ is stationary while the outer cylinder of radius $R_{o}$ moves about the axis at $U$. Assuming the viscosity of the fluid to be $\mu$, the shear stress can be expressed as:

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

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Which of the following velocity measurement methods are non-intrusive,i.e., the measurement process does not disturb the flow?

**(Select the two correct answers.)**

44 / 44

Which of the following is true about flow separation?

**(Select the three correct answers.)**

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