18AE42

Model Question Paper-1 with effect from 2019-20 (CBCS Scheme)

Fourth Semester B.E. Degree Examination

Note: 01. Answer any FIVE full questions, choosing at least ONE question from each MODULE.

Module -1
Q.01 a Derive energy equation using control volume approach. 8
b Describe the relationship between stream function and velocity potential equation. 4
c Derive an equation for vorticity, ξ 8
OR
Q.02 a In a two dimensional incompressible flow the fluid velocity components are given by 8
= − 4 , = − − 4 . Show that the flow satisfy the continuity equation and
obtain the expression for stream function, if the flow is potential obtain also the
expression for velocity potential.
b In the ideal flow around a half body, the free stream velocity is 0.5 m/s and the 8
strength of the source is 2 m2/s. Predict the fluid velocity and its direction at a point, r
= 1.0 and θ = 1200.
c With a neat sketch explain the concept of circulation 4
Module-2
Q. 03 a With a neat sketch illustrate the typical aerodynamic characteristics at low speeds. 6
b Calculate the velocity of bullet fire in standard air if the mach angle is 300. Take R = 287.14 4
J/kg k and k = 1.4 for air. Assume temperature as 150 C.
c Outline the Types of drag-Definitions with suitable examples 10
OR
Q.04 a Explain the following modified NACA four and five digit series 6
1 series: NACA 16-123
6 series: NACA 612-315
7 series: NACA 712A315
b Consider two different points on the surface of an airplane wing flying at 80 m/s. The 6
pressure coefficient and flow velocity at point 1 are -1.5 and 110 m/s, respectively.
The pressure coefficient at point 2 is -0.8. Assuming incompressible flow, calculate
the flow velocity at point 2.
c A light airplane weight 10000 N, its wing span measures 12 m, its chord measures 1.8 8
m, and a payload of 2000 N is anticipated. Predict (a) the take-off speed if an AOA of
80 is desired, (b) the stall speed of the conventional airfoil (c) the power required by
the airfoil during cruise at 50 m/s. Assume Cl = 1 @ 80 AOA and Clmax = 1.72.
Module-3
Q. 05 a Briefly explain the following elementary flows with neat sketches and write Ψ and ɸ 8
for each of them (a) Uniform flow (b) Source and sink flow
b Derive pressure coefficient using non-lifting flow over a circular cylinder, find the 8
location on the surface of cylinder where the surface pressure equals the free stream
pressure.
c Write a short note on D'Alembert's paradox 4
OR

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Q. 06 a With a neat sketch explain the kelvin’s circulation theorem and the starting vortex. 4
b Derive an expression for lift curve slope for a symmetric airfoil using classical thin 8
airfoil theory.
c Derive an expression for lift curve slope for a symmetric airfoil using classical thin 8
airfoil theory.
Module-4
Q. 07 a Derive the expression for the induced angle of attack and induced drag coefficient 8
using elliptical lift distribution.
b Derive the expression for the induced angle of attack and induced drag coefficient 8
using general lift distribution.
c Discuss lifting surface theory and vortex lattice method for wing 4
OR
Q. 08 a Derive an expression for lift coefficient and induced drag coefficient in terms of 10
circulation strength Γ(y) for a finite wing through Prandtl’s classical lifting line
theory.
b Derive the expression for the velocity induced by infinite vortex filament using the 5
Biot-savart law.
c Derive the Vortex filament: Infinite and semi-infinite vortex filament expressions for 5
incompressible flow.
Module-5
Q. 09 a Explain the following with a neat sketches 8
A. Drag-divergence Mach number and sound barrier
B. Transonic area rule
b Discuss the advantages and disadvantages of high lift devices 6
c Explain the difference between thick and thin airfoils 6
OR
Q. 10 a Write a short note on Source panel & vortex latice method. 6
b Outline the leading-edge and trailing edge slats aerodynamic characteristics 6
c Outline the Subsonic and Supersonic leading edges with relevant sketches 8

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