Engineering Questions with Answers - Multiple Choice Questions
Aerodynamics – Uniform Flow
In the below figure, which of the following flow is shown?
a) Vortex flow
b) Uniform flow
c) Doublet flow
d) Source flow
Explanation: Uniform flow is the one in which each particle in the flow moves in a line with a constant speed. Also, in uniform flow, the flow parameters do not change from time to time. They remain constant throughout the flow.
The flow in which the parameters do not change with respect to time is called as ________
a) unsteady flow
b) transient flow
c) steady uniform flow
d) continuous flow
Explanation: The flow in which the flow parameters do not change with respect to time is called a steady uniform flow. The steadiness and uniformity need not occur together. The flow particles move in a line with constant velocity.
The flow in which the flow parameters change from one point to other is called _________
a) uniform flow
b) non-uniform flow
c) steady flow
d) linear flow
Explanation: The flow in which all the hydrostatic parameters change from one point to other is called non-uniform flow. The changes may be in direction of flow or in the direction perpendicular to the flow. The example of the changes perpendicular to the flow is the flow over the solid bodies.
The tapering pipe is an example of __________
a) steady uniform flow
b) steady non-uniform flow
c) unsteady uniform flow
d) unsteady non-uniform flow
Explanation: The flow in a tapering pipe has variable geometry. The cross section of the tapered pipe is not uniform but the rate of fluid flow is constant throughout the flow. Any duct which has non-uniform cross section but the hydrostatic parameters remain constant fall under this category.
In unsteady flow, the streamline also changes from instant to instant.
Explanation: All the hydrostatic parameters change from time to time in unsteady flow including the velocity. The streamline defines the direction of flow when a tangent is drawn from any point in that flow field. As the velocity changes, the streamlines to changes.
What does the below figure show?
Explanation: A group of streamlines forming a passage through which the flow passes is called as stream-tubes. They are bounded by a number of streamlines. The fluid may enter or leave the surface through the ends of the stream-tubes.
In steady flow, pathline and stream lines are _____________
d) slightly similar
Explanation: A pathline is a path followed by a fluid flow particle. Whereas, streamline is a point in the fluid flow at which if a tangent is drawn, it gives the direction of the fluid flow. But in a steady flow, the velocity remains constant throughout the flow, hence the pathline and streamline become the same.
Two pathline can __________
a) intersect each other
b) cannot intersect each other
c) can meet at infinity
d) cannot meet ever
Explanation: Two pathlines can intersect each other because the same particle or the different particle may come again at the same place at different time. Moreover, pathline is just a path followed by the fluid particle. Two or more fluid particles can follow the same path.
Consider a fixed point in a flow. The locus of all the point passed through this fixed point is called as _________
c) streak lines
d) stream tubes
Explanation: The locus of all the points that have passed through a fixed point is called a streak line. The flow will pass through a fixed point to any other point at any instant. The locus of these points is streamline.
Consider a flow over a flat plate of uniform cross section area, the flow moves at a constant speed. Due to a certain disturbance, there is a disturbance in the flow. In the given scenario, which of the following statement is true?
a) The flow remains uniform even after the disturbance
b) The flow remains uniform throughout
c) The flow is the first uniform and after disturbance undergoes non-uniformity
d) The disturbance will change the cross section area
Explanation: At the beginning, the flow is uniform and steady flow. After the disturbance, the cross section still remains the same, but the flow velocity changes and the flow become unsteady.