Questions tagged [aerodynamics]

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2answers
309 views

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 ...
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2answers
75 views

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 ...
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1answer
31 views

Why don't we use feather like structures for hang gliding?

I'm not entirely sure if this is the right site for this question, but I recently went on a Greek Myth Binge and came across Daedalus again, and his famous first hanglider, made from feathers. Now, ...
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2answers
38 views

Is air density calculated using Total Pressure (Dynamic and Ambient) or just Ambient?

I have some wind tunnel data and static and dynamic pressure are logged (temperature too). I need to calculate lift and drag but I’ve been confused whether to use only ambient pressure to calculate ...
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1answer
49 views

Extracting Uncertainty from Numerical Solution

I am performing numerical and uncertainty analysis for an oblique shockwave angle function: $$ \tan(\delta)=\frac{2}{\tan(\theta)}\frac{M^2\sin^2(\theta)-1}{M^2(\gamma+\cos(2\theta))+2} $$ where $\...
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1answer
66 views

What shape does a rod bend into when you push the ends together?

If I have a uniform rod -- And then I push on each end toward the center >--< So it bends ...
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1answer
29 views

What is the cycle of simulation editing?

So this is very general, but... How are simulations for vehicles done? I know that computational fluid dynamic simulations are used, but why are repeated tests of actual hardware done too? Obviously ...
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1answer
78 views

How can i calculate drag on an Angled area?

I want to calculate drag force at special angle on a sphere . There are some grooves on the sphere and these groove have a special angle on the sphere. In other words, I want to calculate drag force ...
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1answer
400 views

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 ...
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1answer
267 views

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 ...
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1answer
173 views

Reducing air flow speed without much backpressure

I am setting up a test-bed for an experiment. Here's what I have. A circular car exhaust like this Image The gas comes out of the exhaust at a velocity, x. We need to lower the gas velocity to X/3 ...
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2answers
1k views

How to generate a NACA 6-Series Airfoil analytically?

I asked this question over at Aviation.stackexchange but after that I figured it might be better to place it here. Especially since there were really good answers on the NACA 5-digit-Series airfoil ...
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1answer
31 views

Vertical wind measurements

How can the vertical wind direction be measured? For a project I have to design a wind turbine and I would like the blades to make slight adjustments based on the wind direction in order to achieve ...
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1answer
22 views

What is the side way force on a flat membrane place perpendicular to the flow of current on one side, and stagnant water on the other

So basically imagine a plate being placed parallel to the direction of flow of water with water flowing with a certain velocity on one side of the plate and on the other side it is almost stagnant. ...
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0answers
30 views

How to properly use the lift-curve slope for divergence calculations?

I was reading Wright and Cooper's writings on static aeroelasticity and I think I'm missing something. To calculate the acting lift, the equation $L = q S a_1 \theta_0$ is used, where $q$ is the ...
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0answers
44 views

Which of these propeller configurations is most efficient?

All propellers shown in the figure above are identical and are operated at identical speeds with four separate (numbered 1 through 4 vertically) configurations illustrated. The physical distance ...
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0answers
33 views

Superimposing a Vector Field onto a Toroid in Matlab

I am a systems and control PhD student in Aerospace Engineering. Currently, I am trying to create a wind shear model of a toroidal thermal "bubble" in Matlab similar to the one in this paper (shown ...
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1answer
40 views

Normal Shockwaves occurrence at cone tip with Angle Theta

I have a question regarding shockwaves. So as far as my knowledge, a flow moving at Ma= 1 will create a normal shockwave ($arcsin(1/Ma)$) , and a flow moving faster will cause an oblique shockwave. So ...
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0answers
13 views

Skelet Theorie, can anyone help?

I am studying Gas dynamics and came across the lift angle approximation as based on Skelett Theorie (in german). I have done google searches on finding this theory but no luck on any information. Can ...
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1answer
45 views

Torque induced regular precession/ nutation calculation and visualization out of attitude Data

I have a rocket body with given Euler Angles, Quaternions and Angular-Velocities for given time steps. And I'd like to calculate the regular precession and nutation for every time step, so that I can ...
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0answers
25 views

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 ...
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2answers
89 views

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 ...
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0answers
41 views

What is the theoretical relationship between sound and mass with respect to the sound barrier as a max velocity?

First post here, forgive me any faux-pas. In regards to compressible flow and accelerating a mass flow, such as in a converging nozzle, I know that you can't accelerate a mass past the speed of sound (...
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0answers
32 views

Determination of a Joukowski airfoil chord (demonstration)

I'm currently studying Aerodynamics, and one thing that I noticed is that the maximum and minimum $x$ coordinate of the airfoils (which are necessary to compute the chord) on the transformed plane (...
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2answers
35 views

Will a lift force be created by the Coanda effect if high velocity air flows under a half-toroid shaped saucer? [duplicate]

I would like to know if a lift force will be created by the Coanda effect from high velocity air that is directed under a half-toroid shaped saucer by a centrifugal impeller. To illustrate how such a ...
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1answer
148 views

Would this air amplifier attachment increase a leaf blower's effectiveness?

With the start of the leaf raking/blowing season just a month away, I have been thinking of a way in which I could make my old leaf blower more effective so I can spend less time doing leaf blowing. I ...
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1answer
191 views

Ceiling or table fan better

I always wonder in directional flow which fan would send colder.air and cool better. I am biased toward table fan as it throws fresh air while ceiling fan throws stale hot air accumaled at top. Please ...
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4answers
8k views

What does “tempered water” exactly mean and how does it help cool the air?

It's from Apple's latest Earth Day commerical called “Can a building breathe”. https://www.youtube.com/watch?v=tNzCrRmrtvE The commercial is about Apple's new naturally ventilated building called "...
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2answers
62 views

Is it possible to generate energy from indoor draft by opening windows on opposite sides of the building?

Wind flow always generates naturally when I opening windows on the opposite sides of the building. Is it possible to put turbine on the way and generate electricity from that? It could be optimising ...
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2answers
58 views

Heating the air inside a turbojet instead of combusting it

Would an aircraft that uses propellers for movement but with a turbo jet like structure where the ignition chamber only heats the air a bit, similar to a hair dryer instead of releasing fuel and ...
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2answers
52 views

Deceptional Pitot Tube

speed measured by pitot tubes is that of the wind speed relative to the aircrafts. Now, this itself depends on weather conditions which can affect wind speeds. So, then why employ pitot tubes at all ...
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1answer
32 views

Using RC scale-down model to pre-test aircraft design

I'm a bit involved into building an actual airplane. And while the guys go conventional ways, I'm trying to look around to see other solutions. One of that is to try and use and RC scale-down model (...
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3answers
79 views

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= ...
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1answer
93 views

RC drone rotor air access

I am attempting to design a "flying saucer." The saucer is an ellipsoidal-ish body with a RC drone inside. I plan to allow for air access to the rotors as shown in the rudimentary diagram below: I am ...
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1answer
116 views

Propeller design

I see on internet, that aircraft propellers most effective blades angle only 15 degrees on every blade. Why propellers not use 45 degrees angle on propeller's blade that give more thrust on the ...
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2answers
47 views

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 ...
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1answer
66 views

Pressure Coefficient with a Minima of 0 on Compressor Airfoils in Cascade

I am a relatively recent BSME graduate working on reproducing the results of a technical paper to strengthen my ANSYS CFX skills. The paper is "Effect of Section Thickness and Trailing Edge Radius on ...
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2answers
67 views

Will a fan that is composed of several fans fixed inside rotating tube work?

I want to design a custom 3D printed fan that would be made of several axial fans that would be connected (fixed) to their cylindrical casing. I am planning to rotate the whole assembly (the cylinder ...
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1answer
128 views

Why does 3D source potential flow only satisfy Laplace's equation in spherical coordinates and not cylindrical coordinates?

3D source potential flow is given by: $\phi = \frac{-\lambda}{4\pi r}$. Laplace's equation in cylindrical coordinates is: $\frac{1}{r}\frac{\partial }{\partial r}\left(r \frac{\partial \phi}{\...
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3answers
101 views

Formula (or heuristic) for calculating force required for incremental change in angle of attack of an airfoil

Assume I have a system comprising of an airfoil A immersed in a fluid. Further assume, that the airfoil is affixed via two bolts at one end, and is untethered at the other end. The system can be ...
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1answer
804 views

Simple, open source aerodynamics simulation software that can import Blender or Sketchup models? [closed]

What are some basic, open source aerodynamics or CFD simulation software that can import Blender or Sketchup models? I am looking for software that is easy-to-use, free, and suitable for educational ...
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0answers
16 views

Wind behavior and pattern

From the 5 options, which one shows the worse wind effect? Is it (b) because wind speeds accelerate through a gap? But how about in comparison to (c)? Or (d) due to the height and sharp corners? If it'...
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0answers
34 views

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 $c_l$...
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1answer
50 views

How to do Blade Element Momentum Theory Analysis for NACA airfoils?

I wanna perform BEMT analysis on blades of different geometry and not just symmetric thin airfoil. How to do this?
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2answers
57 views

Would a plane lift from ground if in a free treadmill?

I was wondering if the force generated from the engines of a jet plane would lift it up from the ground if in a free treadmill. Would it take off?
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3answers
503 views

How do drag and downforce in a rear spoiler of a car vary with angle of attack?

I ran an two aerodynamic simulations, one for a spoiler angle of 0 deg and the other for the same spoiler declined at 30 deg. The results showed a considerable increase in downforce, but only a slight ...
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0answers
51 views

Determining thrust equations for a custom UAV

I have been tasked to mathematically model and simulate a 2 propeller, 2 motor UAV. But I am struggling with determining the thrust equations, of the propeller, for my design. I know that: Ft = Ct * ...
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1answer
108 views

Wind resistance inside turbulent flow (“prop wash”)

I have an object that is launched from the side of a plane (it is a flare). The question is: what does the flare do while it is proximate to the plane? Will it hit the tail? After accounting for ...
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1answer
34 views

What are some concepts I can look into to aide in creating a 'compression funnel'(?) without the aide of a motor? [closed]

In short I'm designing a 'Humane fly swatter' for my University application into bachelor of Industrial Design. The idea is to utilise the energy of swatting a fly to capture air through an intake, ...
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2answers
102 views

How to determine the banking angle of a quadcopter/helicopter due to unbalanced load along the X-axis?

What theories/equations can be used to determine the banking angle of a quadcopter/helicopter due to unbalanced load, given that the load will only shift along the X-axis