Questions tagged [aerodynamics]
The aerodynamics tag has no usage guidance.
165
questions
8
votes
6
answers
5k
views
Can we add treadmill-like structures over the airplane surfaces to reduce friction, decrease drag and producing energy?
I am curious about a method to enhance the efficiency of passenger aircraft during cruise speeds by integrating treadmill-like structures on the fuselage and beneath the wings without changing the ...
- 81
0
votes
1
answer
46
views
Wind turbines on high-rise buildings?
Recently, it occured to me that there is a lot of "unused" space on flat-top buildings, and so I wondered, whether it wouldn't be a reasonable ideas to put (vertical) wind turbines on ...
- 103
0
votes
0
answers
29
views
Why does CFD over predict shockwave in comparison to wind tunnel?
I ran a CFD simulation of Mach=0.85 flow over an aerofoil and noted that my Cp (coefficient of pressure) plot over predicts the shockwave in comparison to experimental data?
Can someone please explain ...
- 1
0
votes
1
answer
59
views
How does a fighter craft rebalance itself after it fires its munitions and missiles?
How does a fighter craft rebalance itself after it fires its missiles?
Each missile could range anywhere from 40kgs up to 750kgs depending on the model. I am curious to know how a fighter craft ...
0
votes
0
answers
92
views
Unable to validate hypersonic flatplate case in DSMC SPARTA
I'm trying to learn a software called DSMC SPARTA. I'm validating the hypersonic flatplate case mentioned in one of the tutorials on the website (Page 17). This was my test case:
...
- 51
1
vote
1
answer
25
views
Is there a way to 'switch OR engage/disengage' power between two different rotating shafts depending on a set RPM (wind speed)?
I'm a final year mechanical eng student, I'm working on designing a prototype of a 'Hybrid vertical axis wind turbine (VAWT)". This hybrid turbine consists of two types of VAWTs Savonius & ...
1
vote
1
answer
41
views
How will the motion of air be just before the isolation damper?
Let's say I have duct work shown as below. I have air moving from left to right with high velocity.There are two elbows and there is a damper of the same kind just before each of them and there is ...
- 11
0
votes
3
answers
193
views
Why did the Mythbuster's dimple car get better fuel economy?
I'm trying to understand why the Mythbuster's dimple car gets better fuel economy - if it actually would as I'm not
I understand that a golf ball functions by creating turbulent air flow and via the ...
- 103
0
votes
3
answers
156
views
Can a fluid have more or less static pressure than atmospheric pressure in atmosphere?
We assume static pressure of a fluid coming out of a pipe or nozzle of gas turbine with high temperature and velocity is equal to atmospheric pressure, which confuses me for some point.
Does it mean ...
- 125
0
votes
2
answers
56
views
Why are there two fans in open circuit wind tunnel in laboratory?
In an experiment in hydraulics lab of my college, very recently someone asked me, why were there two fans in the open circuit wind tunnel.
That wind tunnel is used for conducting experiment for ...
- 23
0
votes
0
answers
25
views
Honda NR 500 Windscreen
I'm looking for the story of this extremely unusual bike. I found very interesting the experimentation done.
When talking about this bike, most people think about oval piston, but my question is about ...
0
votes
2
answers
195
views
Multiple inline fans
I have a chimney with a single 100 cfm exhaust fan. If I would add a second similar fan in the same chimney,in line with the first fan, what would happen? Would I move 200 cfm? Would I still move 100 ...
- 1
0
votes
2
answers
110
views
How to theoretically determine the flow rate for a fan design?
I am trying to design a ducted axial fan. The fan will be pulling air through a filter, and ejecting out into the atmosphere (For a CO2 direct air capture application). However I want to start with ...
0
votes
0
answers
66
views
Density or Pressure based solver CFD
I’m currently trying to simulate the 2d cross section of a bullet using Ansys Fluent but am really confused about which solver type to use- density or pressure based?
Conditions:
Transonic (M=0.8)
...
- 1
0
votes
1
answer
60
views
What are the limits on plane speed?
I was thinking about an extremely narrow object and considering that I think in the ideal case it could only deal with the force of collision with air particles at the front of the projectile (...
- 101
0
votes
0
answers
30
views
Pitot and static port placement - How to choose the ideal location
Forgive the this topic placement as it might be similar to other older ones (Although I a bit sure that the main contents might be different than other older ones).
In the upcoming days I will have a ...
0
votes
0
answers
19
views
How Does The Aerodynamics Of This Hanging Rotating Wing VAWT Turbine Function?
We are examining videos of this very fast rotating "hanging VAWT" shown on Youtube:
https://youtu.be/O2MZsK0mvBk
https://youtu.be/7hVQ_rVNRUI
It say in the text description that "...
0
votes
0
answers
32
views
how to calculate drag force (to be used later in the calculation of drag coefficient)
I'm working on a school project for car design (M segment car) we already found an open source Toyota model and can get the final answer online, but I want to know how can I calculate them
what's on ...
1
vote
1
answer
179
views
What is the approximate horsepower/kW output of a cyclist riding a bike at near ~300km/h?
In 2018, a female cyclist set the outdoors record for fastest cycling clocking in at almost 300km/h. (https://en.m.wikipedia.org/wiki/Denise_Mueller-Korenek), and I am curious to know the approximate ...
0
votes
2
answers
188
views
How to calculate missile's radius of turn?
I want to make a simple simulator game and in this game there is a missile that must hit something.
The problem is, I can't find the equation to calculate its radius of turn.
The game is a simulator ...
0
votes
1
answer
43
views
Scroll design for off the shelf tangential/cross flow fan rotor
I'm trying to figure out a somewhat optimized fan scroll shape for a cross flow fan rotor I aquired. However I seem to have vastly underestimated the complexity as I have a lot of trouble finding ...
- 1
0
votes
1
answer
46
views
How to calculate the increase in air speed from a wind nozzle / concentrator?
Given an inlet wind speed of $v_1$ and nozzle inlet area of $A_1$ and an outlet area $A_2$ what would be the outlet velocity. The nozzle/concentrator is positioned in an open field where the wind is ...
0
votes
1
answer
97
views
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 ...
- 101
0
votes
1
answer
127
views
How air dam reduce drag and lift?
Few questions about air dam(flexibile vertical plate on front bumper)
What is main purpose of air dam in car industry, reduce drag or reduce lift(increase downforce)?
How dam reduce drag if : a)...
- 221
0
votes
1
answer
30
views
Converting differential pressure
I need to submit a lab report.
I've measured:
Differential pressure [Volts]
Flow rate [Hz]
Flow Rate [m^3/s]
In my report I need to get the Pressure Differential in Pascal but how can I convert ...
- 3
0
votes
1
answer
64
views
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 ...
- 3
0
votes
3
answers
76
views
Releasing compressed air with the loudest pop
Due to the dry summer I've been thinking about theory of making cracker/banger without fire. Would connecting a nozzle (de Laval?) to quick release valve from small cylinder with the pressurised air ...
2
votes
2
answers
389
views
How do water tunnel experiments compare to wind tunnel experiments?
I recently stumbled across the water tunnel videos by this guy:
https://youtu.be/quDLzxmJl5I?t=838
He states that for his "high flow" experiments the water speed is at 0.668 m/s. The car ...
- 135
-1
votes
2
answers
41
views
Governors and acceleration effect on IC engine
If a car is moving with a constant velocity this means that resistive loads (like air drag friction) should equal the driving force from the car; but I know that the governors always cancel the effect ...
- 50
-1
votes
1
answer
116
views
Angle of attack on variable pitch propeller?
For a variable pitch propeller where the angle of attack can be adjusted during flight, are the individual blades similar in design to standard propellers, with a low angle of attack at the edge of ...
- 3
-1
votes
3
answers
327
views
Why do air-to-air missiles have tail fins?
That sounds like a stupid question but hear me out.
For something like a rocket where the goal is to fly in a straight line the use of the tail fins is obvious. But air-to-air missiles are designed to ...
- 1,901
0
votes
1
answer
100
views
What aerodynamic equation should be used to determine the drop in air pressure over an airfoil embedded within a vertical pipe?
I have a conceptual idea for a thruster for a VTOL aircraft/drone which should produce lift by utilizing a upward-flowing airflow to produce low air pressure over the top surface of an airfoil that is ...
- 271
0
votes
0
answers
52
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.
1
vote
1
answer
175
views
Where is best place to install vortex generators if race car diffuser stall?
If flow separate in high AoA diffuser, vortex generators can help to delay separation.
Where is best palce to install VG for flat floor + diffuser configuration , in front leading edge of diffuser or ...
- 221
1
vote
1
answer
274
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 ...
- 111
-1
votes
2
answers
202
views
What are the practical applications of Centre of Mass & Centre of Gravity?
I have learnt COM and COG are different things if we have non uniform gravitational field i.e. mass will be same at anywhere but gravity will be different. I want to find practical examples of both ...
- 57
2
votes
3
answers
229
views
Why wind turbine dont use high lift coefficient airfoils?
All wind turibne use low lift coefficent airfoils from 1.0 to 1.5.
Why not use high CL airfoils to get maximum torque?
http://airfoiltools.com/airfoil/details?airfoil=s812-nr
- 221
-2
votes
1
answer
60
views
Why wind turbine with more blades rotate slower compare to one or two blades?
Why wind turbine with more blades rotate slower(lower RPM) than turbine with just one or two blades, if both has equal diameter on same wind speed?
Often people say more blades have more drag, but ...
- 221
3
votes
3
answers
1k
views
Is the main goal for wind turbines to take maximum energy for a given diameter?
If you increase the number of blades, that will increase torque, for the same RPM you get more power,...simple logic
So why only three blades, is main goal for wind turbine take maximum energy for ...
- 221
0
votes
2
answers
76
views
Kelvin's Circulation theorem applied to a cup of tea
Recently, I dipped my spoon into my tea. I saw that as I dipped my spoon into my tea, two vortices formed at both edges of the spoon. I guess this is similar to vortices forming at the end of ...
- 3
1
vote
3
answers
718
views
Is the drag coefficient/velocity of of a vehicle based on frontal area?
Does the frontal area of a vehicle determine the velocity/drag coefficient of a car?
A Ferrari 458 has a Cd of 0.33 while a Corvette C6 has a Cd of 0.29. Does this mean the Corvette will have less ...
- 11
0
votes
1
answer
42
views
Convert from mm of water to Coefficient of pressure (Cp) [closed]
Okay,
I have this value in mmH2O (2.650) and am not sure where to go next to convert it to aerodynamic parameter pressure coefficient please?
mmH2O * 9.8066 = N/m2
???? What do do next please?
I ...
-2
votes
2
answers
93
views
How can a car travelling at a higher speed may cause it to lift off from the ground?
Many Sports cars and other high speed and performance ground vehicles have a rear wing attached to its rear, and a splitter attached to its front. From what I understand, the rear wing (which takes ...
- 1,337
0
votes
0
answers
41
views
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 ...
- 1
0
votes
0
answers
64
views
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 ...
- 133
0
votes
1
answer
95
views
Why flow around an airplane is different in different frames of reference
In the book Fluid Mechanics by Yunus Cengel it was written
"Flow around an airplane, for example, is always unsteady with
respect to the ground, but it is steady with respect to a frame of ...
- 3
0
votes
0
answers
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 ...
1
vote
3
answers
2k
views
Does more downforce affect the acceleration and top speed?
How can downforce make a race car faster, apart from being faster around corners? I just recently learned that downforce can help a car accelerate from 0-60 mph faster. Usually, I thought drag didn't ...
user34865
1
vote
3
answers
1k
views
What affects a car's overall top speed?
I've always wanted to know how a car's top speed could be determined. Usually, I thought it was horsepower and aerodynamic drag. I learned that weight can affect top speed, but I've recently found out ...
28
votes
4
answers
9k
views
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 ...
- 281