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Questions tagged [aerodynamics]

169 questions
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How can a piece of paper be shaped to guarantee it falls slower than a plain sheet of paper?

My son and I are playing "MAKE" (think "HORSE") and we challenged ourselves to build the slowest falling object using only a sheet of paper. We cannot build anything that falls slower than a plain sheet of paper. Any ideas?
Corey Alix
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Air velocity through a tunnel 5,000 feet long and 30 feet in diameter?

I am an architect in need help with an aerodynamics problem for a design that I am developing. I need to know the the potential velocity of air moving from one end of a pipe to the other if any with a constant 20° difference in temperature. The…
Ken Miller
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How to Find Drag Force from Skin Friction

Just wondering if someone can please can give me some idea, as to how I can solve this question that is not related to current study. I haven't been able to work out where to start with it just yet. Air flows parallel to the surface of a smooth flat…
Rob Wilkinson
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How can I generate smoke (or mist) that leaves no residue?

I have to visualize flow over some designs in my wind tunnel. However, my advisor has stated that previous students have wrecked the machine when they have used oils and I think Dry Ice might interfere with the results owing to its different density…
Saif Ul Malook
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How to evaluate the fuel consumption rate of an air conditioner in a vehicle?

Using two cases studies: I. When the windows are wound up and air conditioner is turned on. II. When the windows are wound down and air conditioner is turned off. Case studies are evaluated for driving in city and highway but more importantly how…
Manuel Charles
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Fan starts making noise and air flow is reduced considerably

Yeah.. I dont know if this belongs here, I coulnd´t find a proper stack exhange site for this but it sort of involves physics I guess so... yeah. Basically, I have a ventilator, that after a few mins of functioning starts making this weird noise,…
Artemix
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ENLIL road-side vertical turbine - creating drag?

A company called Devecitech has just created what it calls the 'ENLIL' vertical axis wind turbine, that sits at the side of a highway generating electricity from the wind-power created by passing cars Video here: http://devecitech.com/ My question…
Black
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What is the optimal streamlined shape?

We all know the typical streamline shape which looks like a tear. But what is the optimum shape (for speeds 0-200 km/h)? Is the front a half sphere or is it an ovoid? How are the sides and the end formed? Can it be described in a formula or in a…
Thorsten S.
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An Argument from Kelvin’s Circulation Theorem

Page No. 318, John Anderson’s “Fundamentals Of Aerodynamics”. The author here states from Kelvin’s circulation theorem that the initial circulation around a closed loop including the airfoil when the flow is stationary, which is 0, must be equal to…
RedHelmet
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Proving Kelvin’s Circulation theorem

I’m following Anderson’s Fundamentals Of Aerodynamics. However, the proof for the above theorem is not provided. Every time I try it, things get really lengthy and cumbersome. Is there some nice and short method to getting around to prove the time…
RedHelmet
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How heatseekers change their course?

Heatseeker when locked on target(say a jet), follows the target until the it is hit, what happens when target is moving and changing it's direction.how does the heatseeker it's changes direction at such high speeds?
McGucket
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Wind drag by a solar panel on an RV trailer

I installed my solar panel a couple weeks ago and now I'm not sure if I did it right. The first pic is mine the second is the other guy. it’s what brought up the curiosity, as this guy has the same trailer and the same 200w panel as i do. See how…
rasmukri
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Is it known how streamlined the Shinkansen 800 bullet train is when on rails?

This question is different from What is the optimal streamlined shape?. That question is probably about an ideal situation of flowing through space with no gravity in a fluid with zero viscosity and infinite bulk modulus. This one is about a real…
Timothy
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Why does the tapered part of a Wing have such high coefficient of Lift?

If we take a Trapezoid wing shape as an example and see that it has low $c_l$ near the root of the wing and very high $c_l$ at the tip. The Lift generated, however, is reversed to the that of the $c_l$.
Sherlock Homies
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Max Lift to drag ratio

I have a question that I can't solve. Coefficient of drag= x, Coefficient of Lift= y, it is given that x= 0.015 + 0.05*(y^2), FInd Max Lift to drag ratio and I know that Lift to drag ratio is L/D= Coefficient of lift/Coefficient of drag. Can anyone…
josh
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