# What is Aerodynamics: Definition and 241 Discussions

Aerodynamics, from Greek ἀήρ aero (air) + δυναμική (dynamics), is the study of motion of air, particularly when affected by a solid object, such as an airplane wing. It is a sub-field of fluid dynamics and gas dynamics, and many aspects of aerodynamics theory are common to these fields. The term aerodynamics is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air.
The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, which was first demonstrated by Otto Lilienthal in 1891. Since then, the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations has formed a rational basis for the development of heavier-than-air flight and a number of other technologies. Recent work in aerodynamics has focused on issues related to compressible flow, turbulence, and boundary layers and has become increasingly computational in nature.

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1. ### I Navier-Stokes equation in a triangular coordinate system

The Navier-Stokes equation is solved in a vector grid in a Cartesian coordinate system. That is, rectangular. But does a rectangular mesh relate to what happens in a gas or liquid, and is it better to use a triangular mesh? Undoubtedly, it is incredibly difficult to take into account all the...
2. ### Available Wind Energy Calculation

For the avaliable power to be harvested in free-streaming wind: P=1/2QU^2_infinite (Q: mass flow rate, U_infinite: velocity of free-streaming wind) And Q is defined as: p x U_infinite x A_d. (p: density of air, A_d: Area of disc) I cannot understand the reason of taking the area of disc, A_d...
3. ### Induced drag relation with speed

Hi everyone. I was wondering if you guys could explain me why I saw people say that: Induced drag changes for a factor of 1/V2 Induced drag coefficient for a factor of 1/V4 If I don't make any mistakes, Drag = 1/2 rho * S * V² * Cd. Manipulating the formula I find, 1/Cd = 1/2 rho * S * V² *...
4. ### Mathematical model for drag on tether

I have a model for airs density as a function of height I would imagine the speed can be describes as the angular velocity times length The coefficient of drag can be found online, seems to be around 1.17 for a cylinder It seems to me that im going to need an integral somewhere, but can't quite...
5. ### I [Questions] Modeling a Baseball Pitch Trajectory in 3D Space

I am currently taking some time off of college (I am a sophomore), and I'm trying to continue coding and experimenting with Calculus-y math as I'll be going into Calculus II and then III when I go back. I am currently trying to develop a 3D baseball pitch visualizer for my own purposes. I am not...
6. ### Aerodynamics of Insect Flight

I am putting this in General Discussion because it could go into either biology or aerodynamics. Remember how bumble bees were not supposed to be able to fly aerodynamically? This explains why that is wrong. Here is a podcast I just found (came out in 2019). The two podcast guys interview...
7. ### Using the surrounding airflow to deduce the physics around UAP/UFO

TL;DR Summary: Using the surrounding airflow to deduce the physics around UAP/UFO Now that NASA is in the mix for investigating UAP/UFOs - I started wondering at what their approach might be. I'm thinking they might be able to work from the outside in, toward the object/sensor(y) artifact...
8. ### Good books/resources for getting into aerodynamics?

TL;DR Summary: I want to know some good resourced on aerodynamics and the viability of a project I want to make. Hey everyone! First post here, so if I do something wrong please do tell me :) What are some good resources for getting into aerospace engineering and aerodynamics? I currently have...
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### What is aerodynamics function of front active lip spoiler?

This is question for aerodynamicist, so I put it here in aerospace department. (Mechanical engineers don't learn aerodynamics at university) What is aerodynamic function of active front lip spoiler (on video) and what is function of flexibile plate infront of front tyers(picture)? Why reduce...
10. ### Engineering Aerodynamics textbook at the graduate physics level

Hello, Can someone recommend me a good textbook to (self-)study aerodynamics, optimally with focus on aircrafts. I am a graduated student in physics and therefore familiar with all the basic concepts of fluiddynamics and calculus. But, apart from that, I have no further knowledge in the field...
11. ### Aerodynamics Monographs: Recent Advances in High Mach Subsonic Flight

Summary:: I'm looking for recommendations of recent aerodynamics monographs which treat high Mach number subsonic (pre-transsonic) flight thoroughly. I'm looking for recommendations of recent aerodynamics monographs which treat high Mach number subsonic (pre-transsonic) flight thoroughly. I...
12. ### I Estimating Vertical Wind Speeds: T_a, T_s, & P_a

Hi all, I have some data from an automatic weather station, with recordings of both 2m air temperature and 2m air pressure and also the surface temperature. Is it possible to estimate vertical wind speeds between the AWS and the surface based upon this data? Imagine T_a = 15 degrees and T_s =...
13. ### Calculating Vehicle Speed based on Downforce (Aerodynamics)

First off: I'm currently working on an RC car heavily focused on aerodynamics for a Project I'd like to add to my Uni application. I've created a model, ran it through CFD and came up with some numbers. Now I'd love to plot out an equation that displays either speed or acceleration in dependence...
14. ### I Ceiling fan pressure increase or decrease

Would air pressure increase or decrease due to a ceiling fan in a room?
15. ### [Aerodynamics] Bernoulli's equation and Pressure Coefficient

We know that the definition of the pressure coefficient is $$C_p=\frac{p-p_\infty}{q_\infty}$$, where ##p## is the pressure at a point, ##p_\infty## is the ambient pressure (free-stream), and ##q_\infty## is the free-stream dynamic pressure. We also know that the Bernoulli's equation is...
16. ### I Lift Force of a Rotating Sphere in the Air

Hello, I would like to ask one question. What is the equation for the lift force of a rotating sphere when flying through the air: m = 0.25 g v = 130 m/s angular velocity = 105 rad/s radius = 3 mm air density = 1.2292 kg/m^3 air pressure = 101200 Pa air temperature = 15 °C = 288.15 K If anyone...
17. ### Aerosol particles, how do I calculate this?

Aerosol particles with an average diameter of 5 μm and a density of 1000 kg / m3 are spread to a room with a floor area of 20 m2 and a height of 3.5 m. How long does it take for all 5 μm particles to settle on the floor (dry deposition)? The answer should be 1 hour and 20 minutes.
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### A Is fluid mechanics (aerodynamics) still being discovered?

Is fluid mechanics,particularly aerodynamics still being discoverd (like math for example) or everything has already done long time ago?

20. ### I Help Regarding Application of Bernoulli in a Boundary Layer

Hey all, I recently took an aerodynamics exam that included the question "Please Explain how the Bernoulli Equation can be Applied Inside a Boundary Layer". Now, it is my belief that the Bernoulli equation, defined by my textbook as P+0.5ρV2=ℂ, requires inviscid flow to be properly applied...
21. ### Grad School Flow Simulation PC Build

Hey everyone, I'm coming to the end of my Mechanical Engineering B.S. degree and I've been in the process of applying to mechanical and aerospace PhD programs. I want to do research in fluid mechanics; I have some expereience in hypersonics from a Research Expereince for Undergraduates NSF...
22. ### Aerodynamics problem -- Hockey stick hitting another player

I thought it would make sense to use the formula f=m*a, but I do t know the acceleration and I don't know what is the average acceleration of a hockey club (guess it depends on strength of the player?).
23. ### Help with best aerodynamic shape of undertray for maximum downforce?

What is best theoretical shape of undertray for maximum downforce , maybe wing shape or venturi shape? classic "venturi shape" with diffuser "wing shape"

25. ### I Why does wind blow leaves in circles?

Earlier today I realized that, when a strong gust of wind would blow through my area, it would pick up leaves off the ground and typically blow them in circular patterns, and typically the leaves would go in at least several complete circles before coming to rest back down on the ground. Why is...
26. ### When a bird flaps it's wings up, doesn't the pressure drop below?

I am trying to understand how birds fly. If you consider a plane, using it's engine & streamline shape of the wings, it can create a low pressure region above the wings and high pressure region below and this makes it fly and the upward force is proportional to the speed. Birds seem to flap its...
27. ### Best aerodynamics video lectures

Do you have some links of best aerodynamics video lectures?
28. ### Aerodynamics -- Warehouse fans blowing toward each other

Hello, all. I work in a warehouse, and in an elevated work area. It's warmer up there because heat rises, but we have a few fans meant to help cool us. Unfortunately, one out of three fans is facing toward another, and I've been trying to explain to my coworkers that if one fan faces another...
29. ### Discovering Train Friction: Measuring Aerodynamics on Rails

Summary:: How can I measure the friction of a train with its rails and the air. How can I measure the friction of a train with its rails and the air. You can assume that the face of the train is like the picture below. If you need any specifications just let me know
30. ### Aerodynamics - Question about wingtip shapes

Short of picking up an aerospace engineering book and learning a lot of complex math, I figured I'd ask here. Looking at the wing tips of planes like the Spitfire, P-63 Air Cobra, P-47 Thunderbolt, A6M Zero, etc... you'll notice the wing tips are rounded. Looking at the wing tips of the P-51...
31. ### Aerodynamics - why wings create lift - current vs historical discussions

My son and i were discussing aerodynamics and he brought up a paper from https://phys.org/news/2012-01-wings.html It seems that the latest discussions seem to completely discount the differential velocity of air flow as a cause of differential pressure, but point to a differential pressure...
32. ### Automotive I Want to Learn Aerodynamics

I don't understand aerodynamics and want to learn it. For example, there are three different cars, car 1, car 2, and car 3 (please see attached image). The power of all cars are similar, 1000 HP. The nose (front) of the car 1 is 90 deg, car 2 is 60 deg, and car 3 is 30 deg. They all have to run...

Why does a helicopter blades operates in an advancing direction while the other, the retreating blades travels backwards? That is, what would happen to the helicopter if the retreating blades were to travel forward like their advancing blades counterparts?
34. ### The aerodynamics of a car (calculating downforce)

Summary: Basicly i am trying to find out if there's anyway to calculate the diffrence in pressure underneath and above the car so i can calculate the downforce Hello I am doing a project about aerodynamics of a formula 1 car when i wanted to do calculations of how much downforce each...
35. ### Golf Ball Flight Aerodynamics

Summary: What could affect Magnus force's magnitude and direction except for speed and spin? Most golf flight simulators model the coefficient for drag (Cd) and lift (Cl) as a function of the relative spin ratio (rsr), where rsr = spin * radius / speed. In Figure 1, parameters of two similar...
36. ### Do surfaces ahead of propellers decrease thrust?

Hi! I have had this question for ages, nearly impossible to find anything on the web. My experiments confused me even further! Its concerning the blockage effects of surfaces ahead of a propeller. For example let's consider the usual dual vectoring propellers on the sides of airshipcars like...
37. ### Aerodynamics and Torque calculation

Hi :) I have to mount solar panels to columns. And for the stress calculations, I can't calculate the torque :( Could you help me out?
38. ### Boeing Boeing 737 Max MCAS System

Hi, I have a question regarding the tragic crash of the latest 737 Max. Is it not a huge error in the flight laws and the MCAS software to execute a nose down maneuver at any altitude? Should the system not have a rule to prohibit such a maneuver below a minimum altitude threshold? I'm also...
39. ### Calculating the cl_max of a wing from airfoil characteristics

Hi, is there an appropriate method to get the maximum lift coefficient (cl_max) of a wing from the polars of the section airfoils? The background is that I cut a arbitrary wing into a certain number of sections. After that I use Xfoil to compute the local cl_max. Since this approach neglects...
40. ### Aerofoil Reynolds number, meaning of a statement in my homework

Homework Statement hello, i have been given a piece of homework which is determining the characteristics on an aerofoils boundary layer. In the brief the following statement is made with no context “Aerofoil is flying in chord Reynolds number 0.2x10^6” am i correct in saying that is the point...
41. ### Hovercraft Lift: Measuring Clearance Height & Lift Force

<< Mentor Note -- thread moved from the technical forums so no Template is shown >> Hello, I built a hovercraft not long ago for an experiment. What I did was applying more power to the motor and looking at how high the hovercraft could go. However, the formula that I was planning to use, uses...
42. ### Aerodynamics of a rocket?

Hi! I'm trying to analyse how aerodynamics affect a rockets movement, I am having a bit of trouble though. Any tips on how i would start out or look? The method is supposed to include differential equations which i am familiar with but have a bit of trouble tieing it all together. Where do i...
43. ### How to calculate the drag force?

Problem How to calculate the drag force of the model helicopter using the given data above? Research Question How does increasing the length of the wing planform of a model paper helicopter affect the time it takes the helicopter to fall to the ground and hence the air resistance? Variables...
44. ### What is the coefficient of drag on a flat surface?

What is the coefficient of drag on a flat surface? Note: The body is in free fall The object has 2 wings planform (it's a paper helicopter), which is flat The object's wing spin in a circular motion (anti-clockwise) during free fall
45. ### How to use the Prandtl-Glauert rule?

Homework Statement For a flow that is incompressible and low-speed, the aerofoil has a peak pressure coefficient of -0.41. Using the Prandtl-Glauert rule, determine the aerofoil critical Mach number. Homework Equations $$c_p = \frac{c_{p,0}}{\sqrt{1-M_{\inf} ^2)}}$$ Ans for Mcr=0.74 The...
46. ### How to find the velocity of air flow around the aerofoil?

Homework Statement How to find the velocity of the air flow around the aerofoil? Homework Equations U - freesteam velocity β - angle of wing camber The Attempt at a Solution To find the velocity of the air flow at each section of the aerofoil, am I right to say that the horizontal velocity...
47. ### Flow Quality Impact on airfoil pressure distribution

I have collected velocity data for a 3-D grid of test section of a low speed wind tunnel.I have tested airfoils for pressure distribution in the same test section for similar free stream conditions. How do I calculate the impact of flow quality in the test section on the test results of pressure...
48. ### Aerodynamics project help

Hello! I am a High School senior planning on doing a project for my Diploma which is based on Aerodynamics. Now, I have looked into the basic physics that goes behind airfoils and their forces. However, I am looking for an experiment idea that is somewhat higher level (maybe undergrad level). I...
49. ### Defining which cyclist profits the most from slipstream

Homework Statement - Question: Which cyclist (A, B or C) profits the most from cyclist slipstream (also called “aerodynamic drafting”)? - Given: the direction of the wind, the positions of each cyclist; an illustration representing this - NOTE that I am expected to solve this question...
50. ### Would there be turbulence around objects w/o boundary layers

According to wikipedia "The onset of turbulence can be predicted by the Reynolds number, which is the ratio of inertial forces to viscous forces within a fluid which is subject to relative internal movement due to different fluid velocities, in what is known as a boundary layer in the case of a...