III Year B.Tech. AE - I Sem      L   T/P/D   C
4   -/-/-   4
(A52107) AERODYNAMICS - II

Aim:

The Student will learn about vaired pheonomena involving compressible flows.HE/She will learn to do elementry calculations using Normal Shock tables,Oblique shock charts,parndtl-Meyer  Funtion tables as a Preparation toward desgin of high speed aircrafts and high speed wind tunnels.

Tables and charts required to be Supplied to candidates for reference during examination:

• Tables:
• 1.Isentropic Flow Properites, 2. Normal Shock Properites, 3. Prandtl-Meyer Funtion and Math Angle, 4. One Dimensional Flow With Heat Addition, 5. One Dimensional Flow With Friction, 6. Properites of INternational Standrad atmosphere and Chart: 7. Oblique Shock Properites.

UNIT-I

Thermodynamics in Fluid Motion: Definition of compressibility of flow, measure, flow regimes.Review of theromodynamics-concept of equilibrium, Thermodymic systems, Variables of state, The first law of thermodynamics, Reversible & irreversible processes, Perfect gases, internal energy and enthalpy, specific heats,Adiabatic reversible process, Relations for Thermally & Calorically perfect gas, First law applied to irreversible processes, The throttling process or Joule- Thompson process (considered most inportant for application to fluid mechanics), Entropy and second law, Entropy change relations, isentropic
relations.

UNIT-II

One Dimensional Flows: One dimsensional approximation, continuity equation for 1-D flows, Energy equation- incorporation of kinetic energy in Joule Thomposn Process, Reservoir conditions, 1-D momentum equation for inviscid flow, Bernoulli equation for compressible flow, Mach number, 1-D area- velocity relation, Convergent- divergent Channel & throat, Relations between satgaation pressure/density and Mach number, Local reservoir and autual reservoir, Sonic variblies and reservoir varibles, Di9fferent forms of energy equation, Constant area duct as a special case of 1-D flow,, Continuity and momeutum equations for constant area ducts, Experimental flow visualization of a bluff body in supersonic flow and picture of a normal Shock- constant area ducts formed by streamlines entering and leaving perpendicular to the shock. Normal shock waves: basic equations, relations across a normal shock,calculation of normal shock wave properties, measurements of airspeed in subsonic and supersonic flows.Entory rise across normal shockand its relation to pressure rise,. Numerical exercises with normal shock tables.

UNIT-III

Oblique Shock and Expansion Waves: Oblique shock relations,Supersonic flow over wedges withb attached shock,large wedge angle and shock detachment, Oblique shock charts: strong shock and weak shock boundary,pressure,density and entropy rise,Oblique shock of vanishing strength and mach wave,mach angle and mach line,supersonic compression by turning,smooth nearly isentropic turn,Numerical excercise with oblique shock charts,

Regular reflection from solid wall, pressure deflection diagram,phenemenlogical description of shock wave-boundary layer interaction at the wall, intersection of shocks, Mach reflection and slip stream. Numerical exercises with shock reflectionand shock intersection, detached shock wave infront of bluff 2-D body-- variation of its strength starting from normal shock, strong oblique shock,weak oblique shock to Mach waves,shock waves in front of a three dimensional body (phenomenological description only)

Supersonic expansion by turning, Prandtl-meyer function & expansion fan, Shock expansion theory-application to supersonic airfoils. Supersonic flows-- over a flat plate at an angle of attack, over a diamond airfoils at a angle of attack, determination of slip stream angle, wave drag and lift, Numerical exercises with Prandtl-Meyer Function Tables. Numerical exercises determination shock-expansion-slipstream configuration & force calculation on airfoils.

UNIT-IV

More One Dimensional Flows and Subsonic & Transonic Airfoils: Adibatic flows in strraight,variable area channel-Laval nozzles, diffusers, Governing equations, area-velocity relation. mass flow rate, effect of stagnation conditions, back pressure. Choked flow, isentropic flow, ideally expanded, over-expanded, under-expanded flows-appearance of normal shock, Wave reflection from free boundary, Brief outline of operation of supersonic wind tunnels employing convergent-divergent nozzles.

One-dimensional piston motion in a constant area tubes, Jump start,propagation of shock wave in front and expansion wave behind, x-t diagram, particle velocity,pressure density & temparature relations.

SUBSONIC FLOW: The velocity potential,pertubation potential,linearized governing equation in two dimension,The pressure coefficient-Prandyl-Glauert compressibility correction, application to swept wings,critical mach no.., drag divergence mach no..,

TRANSONIC FLOW: The sound barrier.Buffeting,Supercritical airfoils,swept wings at transonic-speeds,2nd order equation for transonic flows,Wing-body combination, Whitcomb's Transonic area rule:application to transonic aircraft.

UNIT-V

Airfoil, Wing and Cone in supersonic Flow: Point mass in stationary air moving in subsonic speed & propagation of wave front, In supersonic case influence zone limited within Mach lines/waves/cones, Principle of limited upstream influence in supersonic flow.

Brief outline of the method of charaterstics-- Statement (without proof) of compatibility relations,application to supersonic nozzle design.

Linerized supersonic flow-governing equations,boundary conditions. Pressure coefficient,application to supersonic airfoils-- LIft,drag,pitching moment.Wedge,flat plate,diamond and biconvex airfoils at small angle of attack.

Airloads over flat rectangular wings of finite span, Delta wing with supersonic leading edge and subsonic leading edge,

Cone at zero angle of attack with attached conical shock; Limited upstream influence in supersonic-comparison of finite cone and semi-infinite cone,Dimensional analysis and dimensional conical variable, Ordinary differential equation for conical flow, Mention of avalibility of computed solution,how to use the standard computed chart,Comparision of pressure rise of wedge and cone of equal semi-angle.

Qualitative aspects of hypersonic flow, Newtonian flow model: windward surface and Lee surface , Lift and drag of flat plate wings at hypersonic speeds.

TEXT BOOKS

1.  Liepmann, H. W., and  Roshko, A., Elenents of Gas Dynamics, John Wiley,  1957.

2.  Bertin, J.J., Aerodynamics for Engineers, fourth  edn., Indian reprint, Pearson Education, 2004, ISBN:  8-1-297-0486-2.

3.   Rathakrishanan  E.,  Has Dynamics, Prentice- Hall of  india.

4.   Anderson,  J.D., Modern  compressible  Flow with  Historical Perspective, third  edn., McGraw-Hill, 2003, ISBN: 0-07-112161-7.

REFERENCES

1.  McCormick, B.W., Aerodynamics, Aeronautics & Flight Mechanics, second  edn., John wiley,  1995, ISBN: 0-471-57506-2.

2. Shapirol A.H., The Dynamics and Themodynamics of Compressible Fluid Flow, Vols. I and II, John Wiley, 1953.

3. Landau, L.D., & Lifshitz, E.M., Fuild Mechanics, 2nd edn., Course of Theoritical Physics, Vol. 6, Maxwell Macmillan International Edition, Pergamon, 1989, ISBN: 0-02-946234-7.

Outcome:

Students will be able to prepare the design of high speed aircrafts and high speed wind tunnels.

• Created
Jun 06, 2015
• Updated
Jun 06, 2015
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