# Aerodynamics Questions and Answers – Nonlifting Flow over Cylinder

This set of Aerodynamics Interview Questions and Answers for freshers focuses on “Nonlifting Flow over Cylinder”.

1. The shape of Rankine oval of equal axes can be found out by substituting ______________
a) Ψ=0
b) Ψ=1
c) U=0
d) U=1

Explanation: Substituting zero for the stream function in the equation = U*y + ((-u/2*pi*r)*sin yields the shape of the Rankine oval with equal axes. This gives us two possible options, each with a different oval form.

2. What will be the shape of Rankine oval when sin θ=0?
a) vertical line
b) horizontal line
c) a point
d) curve

Explanation: Substituting zero for the stream function in the equation = U*y + ((-u/2*pi*r)*sin yields the shape of the Rankine oval with equal axes. When sin=0,=0, a horizontal line is generated through the origin of the doublet, which is the x-axis.

3. What will be the shape of Rankine oval when U*y+ ((-u/2*pi*r) = 0?
a) open curve
b) closed body profile
c) straight line
d) point

Explanation: Substituting zero for the stream function in the equation = U*y + ((-u/2*pi*r)*sin yields the shape of the Rankine oval with equal axes. A closed profile body is a circular cylinder of radius R with the centre on the doublet when U*y+ ((-u/2*pi*r) =0.

4. The amount of lift generated in the flow over a cylinder is __________
a) Infinity
b) Positive lift
c) Negative lift
d) No lift

Explanation: The pressure distribution over the top of the cylinder is perfectly balanced by the pressure distribution over the bottom of the cylinder, and the pressure distribution over the front of the cylinder is also perfectly balanced by the pressure distribution over the back of the cylinder, resulting in no lift.

5. In real life, zero drag is acceptable.
a) True
b) False

Explanation: In actual life, zero drag is unacceptable since we know that drag is caused by viscous factors that cause frictional shear stress at the body surface, causing the flow to split from the surface on the back of the body, causing a big wake downstream and disrupting the flow’s symmetry.

6. A combination of uniform flow and doublet flow gives ______________
a) flow past a circular cylinder
b) flow past a wedge
c) flow past a plate
d) flow over any body

Explanation:

In the above figure, the first diagram shows the uniform flow whereas, the second one shows the doublet flow (source sink combination of equal strength). The combination of these two leads to the flow past a cylinder.

7. The stream function can be obtained by _______
a) sum of stream function of uniform flow and doublet flow
b) difference of stream function of uniform flow and doublet flow
c) sum of stream function of uniform flow and source flow
d) sum of stream function of uniform flow and sink flow

Explanation: The sum of the stream functions of uniform and doublet flow can be used to calculate the stream for the resultant flow. We must examine cylindrical coordinates in this case. = U*y + ((-u/2*pi*r)*sin (mathematically).

8. The flow past cylinder is also called as _________
a) Vortex flow
b) Source flow
c) Rankine oval of equal axes
d) Newton’s ring

Explanation: As Rankine observed, the flow past the cylinder is known as a Rankine oval with equal axes, and the flow parameters on the upper and bottom surfaces of the doublet flow stay the same.

Their names appear in the lift equation for a rotating cylinder. The lift L per unit length along the cylinder is exactly proportional to the flow velocity V, density r, and the strength of the vortex G created by the rotation, according to the equation. where pi is equal to 3.14159 Lift, in a nutshell, is the force exerted by an item that is perpendicular to the direction of the laminar flow. The force is formed by the difference in pressure between the upper and lower surfaces of a shape. This can be achieved by the use of an airfoil shape, a plate shape, and the spinning of a cylinder and a ball.