# Questions tagged [aerodynamics]

A subset of the [fluid-dynamics] tag concerning primarily forces such as lift and drag generated on bodies as they move through gasses or as gasses move through the body (typically air).

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### Is it possible to calculate the skin temperature of an object passing through a gas?

If you have an object passing through a gas at a certain velocity, is it then possible to calculate the temperature of that object using properties like velocity, density, mass and/or others?
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### (Lifting of aircraft wings) Source of centripetal force on a curved streamline?

I am trying to understand how wings lifting work in airplanes. One explanation is found here Basically a fluid portion on curved streamline will experience a centripetal force. This centripetal ...
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### Why doesn't my flight aerodynamics maths work? [closed]

Context: For some context, I'm a game developer and I'm building a flight sim game. My goal is to have realistic flight physics -- not arcade physics. I'm having issues with the maths -- it is not ...
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### Is it possible to use cratering processes to measure the yield strength $Y$ of a material?

I have some questions about the paper The scaling of impact processes in planetary sciences. K.A. Holsapple, Annu. Rev. Earth Planet. Sci. 21, 333 (1993); available as an author eprint on ...
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### Is there a Coandă effect outside the atmosphere?

For example, when air is blown through a spoon in the atmosphere, the air flow bends toward the spoon. People say it's the Coandă effect. So, outside the atmosphere, when we let air blow through the ...
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### Resolve Drag into Vector Components

Assume you have a sphere travelling at a velocity of $30$m/s, at angle $30^\circ$ relative to the local horizontal plane. For the purposes of the below equations please ignore more complicated ...
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### How much kinetic energy does a helicopter use in a hover? [duplicate]

A helicopter just circulates air in a hover and maintains a stable altitude. So, how much energy is used to do this? Using the standard equation $KE = \frac12 mv^2$; then the kinetic energy used would ...
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In one case, the air drives the blade, in the other the blade drives the air. Since each is 'just' the reverse of the other, one might expect that the aerodynamics are the same, with other variables ...
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### Generating lift by Naruto running

"Naruto running" is running with your arms behind you (pictured above). Many characters in the Naruto series are superhuman and can run way faster than a normal human. I thought that they run like ...
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### Calculate work done by a hovering helicopter over time

This is likely to be very simple, but... How does one calculate work done by a hovering unmoving aircraft over time? As in work in Joules. In this scenario, to remain hovering the aircraft has to ...
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### Most effecient negative shape to create laminar flow

I was looking at laminar flow filters to aid in my mycology work I'm doing. Most filters use an aluminum extrusion with fins. I figured the options out there are pretty expensive for what you get and ...
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### Flight time of spherical bullet fired horizontally versus dropped vertically / effect of crosswind on spherical car

Would a spherical bullet fired horizontally from a musket stay aloft longer than a spherical bullet dropped from the same height? I know two similar questions have been asked (Will a bullet dropped ...
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### Car Max Range Equation

In space engineering, thanks to the rocket equation, if you know some properties about a rocket (payload, fuel mass and specific impulse) you can compute the theoretical maximum distance the rocket ...
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### Which control volume is being used? [closed]

Consider the control volume shown in this question To evaluate the lift, the integral form of the conservation of momentum was applied as shown in this solution video (Skip to 2:07 for evaluation ...
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### Drawbacks of a Tip jet helicopter [closed]

A Tip Jet helicopter offers some advantages, i.e. eliminates transmission, torque is lower, etc. Engineers experimented with this design in 1950s, but remains marginal at best. What are the ...
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### What is irrotational flow? How to judge?

For example, when the wing moves horizontally, the direction of fluid flow changes first to upward at the leading edge of the wing and then to downward at the trailing edge. Does it rotate? If the ...
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### Do drones fly because of low pressure above them or high pressure below them?

I was working on some drone battery life solutions and was stuck with the question whether drones fly because of low pressure created above them by the rotor or due to high pressure created below them....
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### Why an aircraft or a ship produce pressure waves both in front and behind them?

I think it is obvious why a pressure wave is produced in front of a moving object but why the rear of it should produce a wave?
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### Why do planes use 1-2 propellers in the front, but drones have 4 on top? [closed]

Planes with propellers normally have one or two propellers in front, facing forward, helicopters have one on top facing up and one facing the side, and drones have four on top facing up. How do the ...
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### Angle of attack and lift: is there a model?

The relation between the angle of attack $\alpha$ of an airplane's wing and the lift $F$ generated by it is quite complex. If I treat air particles as tennis balls hitting the wing at the front, then ...
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### Tone production in Irish Flutes?

Since it's about a technical issue, I thought that this question would fit in here the best (as opposed to the music.stackexchange-site): I'd like to know how tone-production in an irish (wooden) ...
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### What is the lift coefficient of human body?

Assuming we can change angle of attack by changing our hands orientation what is the maximum aerodynamic lift coefficient of human body?
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### Is it possible to substitute wind speed for the speed of an aircraft in the lift equation $L = \frac12 dv^2sCL$

As in, how would you calculate the amount of lift an aircraft experiences, if for example the plane itself was stationary in a wind tunnel but is subject to high wind speeds and as a result ...
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### Does the ideal gas law apply to a moving vehicle?

If for example you have a car travelling along a road. There is obviously a high pressure region in front of the car, where the air is forced around the vehicle. Likewise, I understand that cars will ...
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### Do planes have to be noisy?

I tend to think of noise as an undesirable waste of energy because the generator was not designed for that purpose. But that doesnt mean this waste can be avoided. So I wonder how much of this noise ...
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### How do you find the minimum height to open a parachute for a safe landing?

What concepts/formulas can be used to find the optimum/minimum release height of a parachute?
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### Please explain airflows above and below aerofoils for a layman

I have read about the lift of airfoils a lot recently and just want a few things cleared up. When incoming airflow hits a typical cambered airfoil and diverges into “top” and “bottom” air flows, why ...
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### How to find drag of a cylinder?

How can I find a drag on the cylinder placed in uniform water flow, if I know a velocity field around it?
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### Does cross-sectional area affect the air time of a vertically thrown object?

Factoring in air resistance, I have two objects A and B of identical mass, however have different cross-sectional areas. A has a larger cross-sectional area than B. If I throw both objects directly ...
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### Sound boom the other way around?

We know the sound boom - but is there any effect if a body decreases the speed underneath the sound barrier?
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### Model Rocket Stabilisation

I am designing a model rocket and am using 3 B6-4 Engines. Inevitably there will be perturbation of its trajectory by wind and engine/thrust inconsistencies. The way that I currently understand the ...
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### Force applied by horizontal wind on object

Hello, I have a question for a project I'm currently doing: In a tunnel with no gravity, there is a constant wind blowing through. A sphere in the middle of the tunnel is completely motionless to ...
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### How do floating wind turbines stay upright?

Some designs for floating offshore wind turbines have asymmetric bases. Why, however, is the turbine sometimes based on the downwind side of the float as seen here and here? And, related, what ...
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### How much will a hole in the wing of a bumblebee affect its flying? [closed]

let's assume the holes are round shape in the middle of both wings. if the size is 1% of the whole wing, how much will be the impact? i assume this is not linear, how much will be affected if the hole ...
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### Do smaller aircraft have lower take-off speeds?

Assuming there are two aircraft, each of the same density and each the same shape, am I correct in understanding that the smaller aircraft would have a lower take-off speed? I have explained how I ...
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### Drag of flat plate at any orientation in 3D

I am trying to calculate the force vector on a flat plate caused by wind, when that plate is not perpendicular to the wind. Imagine a sailboat, and assume that its sail is a rectangular flat plate. ...
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Does the shear stress contribute to the moment about the leading edge? And if it does, how can we calculate the moment about the leading edge provided that the shear stress is dependant on the surface....
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### Thrust needed from an engine to reach orbit

Assume you had an airplane with magical engines that didn't need fuel, air or power, to operate. What thrust to ground weight ratio would the airplane need to reach orbit? By ground weight I mean mass ...
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### Why did this table tennis ball rise to the sky? [duplicate]

The nozzle makes the water flow through the upper part of the table tennis ball. If the angle and velocity of the water jet are well controlled, the table tennis ball will rise to the sky. The string ...
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### Why are golf balls the only (famous) object with dimples?

To my knowledge there isn't anything that uses dimples to reduce drag. It's weird to hear why dimples are useful and help the ball go farther while at the same time finding no other examples. I ...
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### Does the supersonic aircraft feels less air resistance than when it flies with velocity less than sound

When ever I see pictures like this of some object flying at speed greater than sound , I see triangular waves . So I got question in my mind that Do supersonic objects weather its bullet or aircraft ...
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### Aerodynamic Force Decomposition

We know that aerodynamic drag is proportional to the square of the velocity of the incoming flow: $$D=kV^2.$$ If I decompose velocity into arbitrary orthogonal $x$-$y$ directions:V_x=V\cos\theta\\...
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### Does the weight on a car's wheels decrease with increasing speeds? [duplicate]

Ignoring the reduction in fuel weight as it burns, does the weight on a car's wheels decrease with increasing speeds? If so, by how much and is there a fomula for calculating that? At what speeds ...
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### Why wasn't the Stipa-Caproni plane efficient in its flight?

The Stipa-Caproni was an experimental italian plane design. Though it has a very peculiar shape, it seems at first glance like it would have pretty good aerodynamic profile since its reference area ...
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### How much aerodynamic heating could we make without leaving the atmosphere? [closed]

When an object goes beyond the speed of sound in air, it will heat up due to the air in front of the object compressing. This can be seen for example during supersonic flights and during atmospheric ...
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### Inverted flight [duplicate]

I've read the answers provided but I'm still confused that if an aerofoil is designed so that air flows faster over the upper surface for the purpose of providing lower pressure and hence lift why in ...
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### But how exactly do you calculate the Joukowsky Airfoil, within a minimal margin of error?

After reading a fair bit of theory around the uses of conformal mapping to solve for the forces of lift acting on a wing, or a 2D cross section of the wing, in relation to the angle of attack. However ...
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### Equations behind mist formation around wings of fighter jet while doing acrobatic turns [duplicate]

Can some point me around equations to study for clouds formations around fighter jets while taking turns at high speeds as witnessed in Ace Combat 7 video game. I want to implement this phenomenon in ...