Questions tagged [aerodynamics]

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I have a problem with my representation of roll in Simulink

I am currently an engineering student and a member of the aerospace club of my engineering school (ESILV) which is called LéoFly. We’re a team of 12 students and are building a Fusex (...
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3 votes
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48 views

How does NASA's QueSST X-59 jet work?

The QueSST (Quiet Supersonic Transport) is a project to create a more diffuse sonic boom in order to use supersonic flight commercially without the usual abrupt 1~2 psf pressure spike damaging the ...
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3 votes
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68 views

Mathematical transformation of a heading angle to a roll angle

I'm trying to understand a function in a SIMULINK example of a path following UAV simulation. The gist is that, the UAV Waypoint Follower block provides a required heading from a list of waypoints and ...
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Convergence problem in RANS simulation of unsteady flow

I am simulating an air flow through a two dimensional rectangular channel. The channel splits into two channels, one of them is followed by a 90 degree bend downwards and leads into a cylindrical ...
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2 votes
1 answer
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Calculating mass flow rate of a scramjet engine?

First post here. I'm an undergraduate ME interested in fluid mechanics. I came across scramjets and I was interested about the engine. I want to calculate the mass flow rate of the engine and I made ...
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2 votes
1 answer
124 views

In horizontal axis wind turbines, why does axial component of absolute velocity stay constant (wake rotation theory)

I am having hard time understanding how does the axial component stay constant through the rotor. Every resource i look just says it is due to mass conservation but never gives the actual conservation ...
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2 votes
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688 views

Formula for "ram rise" that works all the way to orbit

True Airspeed (TAS) is the vehicle speed relative to the surrounding air. My assumption is that if I am in orbit say at 120 km altitude with an instantaneous velocity of 8 km/s my TAS would be fairly ...
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2 votes
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56 views

A Question of Coaxial Rotors and Lift

I'm only a HS physics student, so please bear with my lack of jargon. My question goes like this: In the scenario of two coaxial rotors spinning independently in two different directions, each with ...
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2 votes
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what is the actual meaning, role and aim of $p_0$, $V_{a_0}$ and $V_c$ for Mach-meter?

Roskam, book "Airplane Aerodynamichs and Performance" at subparagraph: "2.5.2 HIGH-SPEED AIRSPEED INDICATORS (COMPRESSIBLE FLOW)" uses the following three equations: a) $\left(\frac{\gamma}{\gamma-1}\...
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1 vote
1 answer
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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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1 vote
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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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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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1 vote
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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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1 vote
1 answer
55 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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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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1 answer
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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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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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1 vote
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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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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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1 answer
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Does the weight of a pilot exponentially affect the necessary weight of human-powered aircraft?

The MIT Daedalus, a human-powered craft, weighed about 31 kg. This was significantly lighter than its pilot during its record setting trip, though I can't confirm the pilot's exact weight. Still, this ...
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Stochastic parametric stability of structures

I am investigating an engineering problem that relates to the dynamic stability of a beam-like structure under the action of a stochastic excitation (say, e.g., a marine structure acted by waves or a ...
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Propeller design software & Javaprop help

I'm looking to recreate a 21 inch diameter RC plane propeller for cruising at 30m/s. I have been using javaprop but after inputting the information such as thrust, rpm and hub diameter the blade ...
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31 views

is there a difference in performance between these two fan designs

These two fans are usually used in hairdryer is there a difference between them in performance if both have same rpm and same outer diameter.
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69 views

What are the advantages of an asymmetrical missile nose cone?

Some rocket- and missile designs sport an asymmetrically conical nose cone. A prime example being the Stunner missile in "David's Sling" surface-to-air system. Several sources (such as ...
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Vortex diameter

There exists clear definitions of the size of a vortex core, but vortices affects it surroundings beyond this core. An example is a wing tip vortex which has a small core, but can be seen as a big ...
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How to determine the stability of an aerodynamic shape in ANSYS Fluent

I have the aerodynamic outer mold line file of a drone. The first task of the school project is to verify that the drone is stable. First, I used the 2021R2 version of ANSYS Fluent to try to find the ...
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35 views

Are there any methods to figure out how aerodynamic a race car is without a Cd number?

For the top speed of a car, I believe it's usually limited by drag and horsepower. However, I've also learned that gearing can affect the top speed and acceleration of a car. Are there any methods to ...
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What is the velocity of a fluid particle at the center of a infinitely long counter-rotating vortex pair?

Let's take circulation strength of each vortex τ and distance between them is r. I feel the answer should be 2τ/πr but my friend is arguing its τ/2πr. So my thought process goes like, if you have a ...
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21 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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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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0 votes
1 answer
74 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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67 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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-1 votes
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53 views

Is this miniature cargo aircraft feasible?

I was wondering if it was feasible to create a cargo UAV with these characteristics: The cargo bay should be similar to the trunk of a sedan car ~400 liters and similar dimensions Mass payload of 30 ...
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-1 votes
1 answer
40 views

Efficiency of propeller with Wind perpendicular to rotation axis

What happens to air flow and propeller efficiency if it is moving with Wind perpendicular to rotation axis. The air is blowing in a direction lying on the Planet of the tips.
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-1 votes
1 answer
41 views

What determines if a shockwave is normal or oblique

So I am studying Gas dynamics and I know the math regarding Normal and Oblique shockwaves, but I am not sure why would one occur and not the other. Is there a rule when normal shocks will occur or ...
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-1 votes
1 answer
47 views

Achieving dynamic similitude by sacrificing geometric similitude?

The goal is to scale up a general aviation aircraft by 15%. Dynamic similitude is the primary goal. I have reviewed research on scaling aircraft models but it seems most of it is focused on creating ...
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-1 votes
1 answer
37 views

What is the most efficient way to heat air?

I'm currently playing with a school project. My goal here is to heat a stream of air to a significant temperature so I can demonstrate air expansion. I have a cylinder, with a few turbines, turning in ...
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