MEL 715 : GAS DYNAMICS
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MEL 715 : GAS DYNAMICS P M V Subbarao Associate Professor Mechanical Engineering Department I I T Delhi A Passion of Doing Adventures lead to a Hi-Fi Science and Technology!!!
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MEL 715 : GAS DYNAMICS. P M V Subbarao Associate Professor Mechanical Engineering Department I I T Delhi. A Passion of Doing Adventures lead to a Hi-Fi Science and Technology!!!. The Shocking News. People had dreamed of flying for many years. A Shocking News ?#$?%? - PowerPoint PPT Presentation
Transcript of MEL 715 : GAS DYNAMICS
MEL 715 : GAS DYNAMICS
P M V SubbaraoAssociate Professor
Mechanical Engineering DepartmentI I T Delhi
A Passion of Doing Adventures lead to a Hi-Fi Science and Technology!!!
The Shocking News
• People had dreamed of flying for many years.• A Shocking News ?#$?%?• 1 million to 10 million years they might be able to make a
plane that would fly ?!?!?!• The United States Army was trying to develop an airplane
in 1903, but the plane wouldn't fly. • The New York Times wrote that maybe in
1 million to 10 million years they might be able to make a plane that would fly.
• Only eight days later two men were successful in flying the first manned plane.
• They were Wilbur Wright and his younger brother, Orville.
A Narrow Gap Between Possibility & Impossibility
• The would-be aeronauts of the nineteenth century closely studied the flight of birds and began building flying machines patterned after avian structures.
• Their birdlike craft failed miserably. • They quickly realized that in reality they knew nothing
about the lift and drag forces acting on surfaces cutting through the atmosphere.
• To fly, man first had to understand the flow of air over aircraft surfaces.
• This meant that he had to build instrumented laboratories in which wings, fuselages, and control surfaces could be tested under controlled conditions.
• Thus it is not surprising that the first wind tunnel was built a full 30 years before the Wrights' success at Kitty Hawk.
• A science called Aerodynamics leading to Gas dynamics.
Motivating Examples
• Re-entry flows • Rocket Nozzle Flows • Jet Engine Inlets• Celestial Gas Flows• Volcanic Gas flows..
Applicability of Continuum Theory
Entry Interface Gas Dynamics
Re-Entry
Gas Dynamics of Re-entry
• A range of phenomena are present in the re-entry of a vehicle into the atmosphere.
• This is an example of an external flow.• Bow shock wave : Suddenly raises density,
temperature and pressure of shocked air; consider normal shock in ideal air
o = 1:16 kg/m3 to s = 6:64 kg/m3 (over five times as dense!!)
• To = 300 K to Ts = 6100 K (hot as the sun's surface !!)
• Po = 1:0 atm !to Ps = 116:5 atm (tremendous force change!!)
Rockets : An Example of Internal Flow
Rocket Nozzle Flows
Jet Engines
Supersonic Jet Engines
Supersonic Jet Engine Inlets
Volcanic Gas Dynamics
Propagation of a Pulsed Protostellar Jet
Protostellar jets are unique in that they have high Mach numbers, are overdense compared to their surroundings, and they are strongly radiatively cooled. A large number of studies have reported the dynamical evolution of such jets: cooling results in the formation of thin dense shells which are easily fragmented into clumps and "bullets".
