Expert: Paul Soderman - 12/7/2010

Question
QUESTION: Hi, I would like to know more about aeronautical
engineering.
can you tell me, how the aeroplane's wings work?
what are aerodynamics and thermodynamics?
what is a propulsion system?
what is a wind tunnel used for?

Any type of help will be appreciated.
Thanks.

ANSWER: Yash
The short story is that the aircraft wings have a shape, angle of attack, and airspeed that cause the pressures on the lower surface to be higher than those on the upper surface which causes an upward force or lift.   Aerodynamics is the study of fluid flow over bodies and the resultant forces and moments.  Thermodynamics is the study of heat processes that do work or cause energy flow due to thermal differences in fluids or masses.  A propulsion system is anything that delivers thrust to a body moving in a fluid such as air.  Wind tunnels are used by engineers to study the flight of aircraft or other aerodynamic bodies in a laboratory setting that simulates actual flight.

Hope this helps.  You can find much information on these subjects on the web such as at:

http://sites.google.com/site/aerodynamics4students/table-of-contents

or  

http://www.grc.nasa.gov/WWW/K-12/airplane/bga.html

Good luck.
Paul

---------- FOLLOW-UP ----------

QUESTION: Thank you so much for your time and help.. I have few more
questions.
what does the term 'fluid dynamics through a wind tunnel'
mean?
Does the term propulsion and aero propulsion have same
meanings?
What are the things that one should take into account while
designing a specific system...like propulsion system?
and what do you think is the future of aeronautical
engineering and how important it is in today's life?

Regards,
Yash.

Answer
'Fluid dynamics through a wind tunnel' is a somewhat awkward way of stating that the airflow in a wind tunnel has properties that can be classified as fluid mechanic:  velocities, pressures, densities, viscosities, temperatures, vorticity, etc.  Aero propulsion refers to methods of providing thrust to a body in flight in air.  Propulsion is a more general term and could refer to the thrust on many things such as a car or bicycle or airplane or bird or person.  Your question about systems is somewhat vague because if you think about it there may be innumerable things that are important to a system such as energy required, heat, pressure losses, size, cost, weight, efficiency, durability, fabrication schedule, etc.  The future of aeronautical engineering will be good as long as people want to fly somewhere, which I believe will be the case for a long, long time.
Paul