P M V Subbarao

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ORIGIN SCOPE OF VISCOUS FLUID FLOWS

• P M V Subbarao
• Professor
• Mechanical Engineering Department
• I I T Delhi

An Essential Engineering for Human (Internal
External) Comforts
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Hans Albert Einstein (May 14, 1904 July 26,
1973)

• Hans Albert Einstein was a Swiss-American
  engineer and educator.
• He was an avid sailor, frequently taking
  colleagues and family out for excursions on the
  San Francisco Bay.
• On his many field trips and academic excursions,
  he took thousands of pictures, many of which he
  developed himself and presented as slide shows.

• In tribute to Einstein's lifelong contributions
  to the field, his former graduate students
  published a book of research in his honor in
  1972, Sedimentation Symposium to Honor Professor
  H.A. Einstein.
• In 1988, the American Society of Civil Engineers
  created the Hans Albert Einstein Award to
  recognize outstanding achievements in erosion
  control, sedimentation and/or waterway
  development.

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Inspiring Words Albert Einstein

• When asked what he wished to become, as a young
  man, Nobel Laureate Albert Einstein said,
• "I want to become a useful person, not a
  successful person."
• Asked what he meant by it, the eminent physicist
  replied,
• "A successful person is one who takes from
  society more than what he gives it.
• A useful person is one who gives the society more
  than what he takes from it."

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Albert Einsteins Opinion on Best Theory

• A Theory is more impressive or useful
• the greater the simplicity of its premises is,
• the more different kinds of things it relates,
• and the more extended is its area of
  applicability.

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The Law of Learning
one fourth from the teacher, one fourth from own
intelligence,one fourth from classmates, and one
fourth only with time.
Mahabharath
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Why Humans Study/ Show Great Concern about Fluid
Flow in his World of Existence ?????
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The Most Ancient (Materialistic) use of Fluid
Flows
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Technology Vs Viscous Fluid Flows
Water Mills
Wind Mills
Mechanical Machine free?
Heat Engines
Steam /gas turbines
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Fluid Flows in Transportation Sector
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Environmental Fluid Flows
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Weather Fluid Flows
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Biological Fluid Flows
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Knowledge of Viscous Fluid Flow for Design of
Artificial Heart Valves
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Fluid Flows for Sports
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Development of Fluid Flow Systems using a
selected combination of Forces

• Systems only due to Body Forces.
• Systems due to only normal surface Forces.
• Systems due to both normal and tangential surface
  Forces.
• Only mechanical forces.
• Only electrical forces.
• Electro-kinetic forces.
• Thermo-dynamic Effects (Buoyancy forces/surface
  )..
• Physico-Chemical/concentration based forces
  (Environmental /Bio Fluid Mechanics

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Major Flow Systems due to Mechanical Forces
Level 1

• Incompressible A vector dominated..
• Compressible Both vector and scalar .

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1930s Flying StoryCruising at High Altitudes
?!?!?!

• Aircraft were trying to approach high altitudes
  for a better fuel economy.
• This led to numerous crashes for unknown reasons.
  
• These included
• The rapidly increasing forces on the various
  surfaces, which led to the aircraft becoming
  difficult to control to the point where many
  suffered from powered flight into terrain when
  the pilot was unable to overcome the force on the
  control stick.
• The Mitsubishi Zero was infamous for this
  problem, and several attempts to fix it only made
  the problem worse.
• In the case of the Super-marine Spitfire, the
  wings suffered from low torsional stiffness.

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• The P-38 Lightning suffered from a particularly
  dangerous interaction of the airflow between the
  wings and tail surfaces in the dive that made it
  difficult to "pull out.
• Flutter due to the formation of thin high
  pressure line on curved surfaces was another
  major problem, which led most famously to the
  breakup of de Havilland Swallow and death of its
  pilot, Geoffrey de Havilland, Jr.

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Major Flow Systems due to Mechanical Forces
Level 2

• Laminar Absolutely Deterministic
• The structured tensors.
• The relations among tensors, vectors Scalars
• Advanced Vector calculus
• Turbulent Statistically Deterministic.
• Concept of ensemble/temporal/spatial averaging.
• Creation of more tensors to develop deterministic
  approach
• The issue of closure.