This is the third video in the series on aerodynamics brought to you by the Science of Flight,
a new brand here on YouTube.
A brand dedicated to aerospace engineering education and software.
In this video we're going to talk about different aerodynamic methods.
So let's get to it.
There are three general approaches at tackling an engineering problem:
theoretical, experimental, and numerical.
These three approaches are also found in aerodynamics as well.
A theoretical approach involves a mathematical analysis using known relationships.
We call these relationships "equations" or "laws".
We use these equations and known parameters to determine unknown parameters.
Now, sometimes, these are simple enough that you can do them by hand on a piece of paper.
Sometimes, they involve lots of calculations, lots of different equations and, sometimes,
a specific algorithm (or a specific order that you're supposed to perform certain tasks).
Usually that's where some of these different methods, that you see there listed, that's how they differ.
Maybe they use different equations, maybe they use different parameters,
and maybe they use a different algorithm.
But they're designed to figure out an unknown parameter based on known parameters
and known relationships.
Right, this is the plug and chug approach.
Now for each of those methods that I have listed,
I'm planning on giving several videos dedicated to each method.
We can explore the method.
We can run through several examples, develop software code for multiple platforms.
So definitely stay tuned.
There's lots of good videos to come.
If there's another method you think that you'd like to hear about go ahead
and throw it in the comments below.
I can definitely cover it.
So yeah, definitely stay tuned.
Another approach is the experimental approach.
This is where you go out to the lab and perform tests to determine empirical approximations
based on the data you collect.
So this would be the test for your answers approach.
Now from an aerospace point of view this usually means building, which can take awhile,
and testing, which could take a while, a scaled model in a wind tunnel
or wiring up an aircraft with sensors to collect data during a specific test flight program.
Now the last approach is numerical methods.
This approach uses computer simulation of mathematical models to arrive at the likely solution.
This is the CFD approach.
Or, if you're a structures person, this is similar to an ANSYS approach where you're doing a lot of
number crunching in the computer, with simulation, to try and determine the likely solution.
Now while some engineers have their preferred method, one they trust more or the one they like doing the best,
the best approach actually uses multiple independent methods to build confidence in the solution.
Confidence, of course, being increased with each independent method used to arrive at the solution
or that confirm solutions from other methods.
Let's quickly go over what a typical aerodynamic design, of maybe like an aircraft or a drone
or something like that, might actually look like.
Now it doesn't have to be this way but it's a good approach, or a typical approach, for this design.
Now a lot of times you might start out with a theoretical approach, which is a quick way to get
"in the ballpark" solutions and have a quick rough estimate, "order of magnitude" type of approach,
to get pretty close to the solution pretty quickly not spending a whole lot of time or money on it.
Now depending, of course, on the results of that then the next step is usually building models
and throwing them into a wind tunnel or building models in the computer and running it through CFD to
get the more refined solution, or the better results.
Usually this takes more time.
It usually takes more money and so that's why it's usually not done first (because of the money
and the time involved) but it's usually in there somewhere.
Then based on your results from those tests, the CFD and the wind tunnel,...
Obviously there might be several iterations depending on what you find out.
You might find out you have too much drag and you've got to adjust the design.
So you'd adjust the design and then you'd throw it into the wind tunnel or into the CFD and you'd retest it.
So there might be some iterations in there, but that's usually a step in the process.
Now after you get through that step and you've built up a lot of confidence in your results, based on a lot of
simulations or a lot of wind tunnel data, preferably both, then a lot of times you'll go on to
the full-scale prototype, or test flight program, stage.
This is where you'll put like a prototype through an actual flight test program and you will sometimes have
different goals of that test program.
For instance, you might be trying to verify values you obtained in the wind tunnel or in the CFD.
You might be trying to perform a parameter identification during flight tests,
using flight tests to determine certain parameters (the testing approach we talked about earlier).
Or you might be determining the handling qualities of the aircraft.
You could have several different goals and actually accomplish multiple goals in the flight test program.
And, of course, after the flight test program is satisfactorily completed
then it would go into production and go out the door to the customer.
As you can see, each approach has its place and has its pros and it's cons and a great engineer
will actually be well-versed in all three approaches.
The idea of this series is to be covering all three approaches, with the different methods
that each contains, so that you can start developing a mastery over them.
And, as I said before, stay tuned there's lots of good stuff to come.
All right, that's the end of the third video.
If you liked what you saw and you want to see more like the video, comment below,
subscribe to the channel, and click that link for the next video in the series.
The question of the video this video is: "What aerodynamic design projects would you like to see
or have you done recently?"
So throw the answer to that in the comments below.
When you're done doing that, click the link for the next video where we're gonna discuss air, fluids,
and whether air is a fluid.
I'll see you then.
