JNTU
JNTU B.Tech III HIGH SPEED AERODYNAMICS Previous Question Paper (November/December - 2018 - R16)
Note: This question paper contains two parts A and B. Part A is compulsory which carries 25 marks. Answer all questions in Part A. Part B consists of 5 Units. Answer any one full question from each unit. Each question carries 10 marks.
Part A
Explain the meaning of stagnation state with an example.
Answer
A stagnation state (or total state) is the thermodynamic state of a fluid when it is brought to rest isentropically. For example, the air inside a pitot tube placed in a high-speed flow is brought to rest, and the pressure measured is the stagnation pressure.
Define a thermally perfect gas. Explain adiabatic process, reversible process and isentropic process.
Answer
A thermally perfect gas follows the equation of state
What is Fanno flow?
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Explain briefly over expansion and under expansion in a nozzle using sketches.
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Define critical Mach number and drag divergence Mach number.
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Explain Prandtl-Meyer expansion using a sketch.
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What is Prandtl-Glauert rule and where it is used?
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How is the flow past a wedge different from flow past a cone?
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What is the difference between intermittent and continuous flow high speed wind tunnels?
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Draw the schematic diagram of a typical shock tunnel and indicate its parts.
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Part B
Explain different regimes of compressible flow from subsonic to hypersonic Mach numbers using diagrams.
Derive a general equation for change in entropy between two states in a calorically perfect gas.
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Derive the energy equation in integral form using suitable flow model.
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Derive the area- Mach number relation for a variable area duct and discuss based on it the nature of flow in converging and diverging ducts at different Mach numbers.
Explain why a converging-diverging configuration is required for the acceleration of flow from subsonic to supersonic conditions.
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Define Rayleigh flow. Derive expressions for pressure ratio, temperature ratio and density ratio in Rayleigh line flow. What do you understand by choking in Rayleigh flow?
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Derive the relationship connecting the upstream Mach number, deflection angle and shock wave angle for an oblique shock wave.
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Discuss using sketches how supercritical airfoil and area rule help in handling drag rise in transonic flows.
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Explain how shock expansion theory can be used to calculate drag for supersonic flow over a symmetrical diamond shaped airfoil at zero angle of attack using a sketch.
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Describe Newtonian flow model for hypersonic flows and derive expression for pressure coefficient.
Derive expressions for aerodynamic coefficients for a flat plate at an angle of attack in hypersonic flow using Newtonian theory.
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Draw a neat sketch of a closed-circuit supersonic wind tunnel and explain the function of each component. Explain how closed circuit wind tunnels are advantageous over open circuit wind tunnels for testing at supersonic speeds.
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Explain briefly the various optical methods of flow visualization.
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