SoME 4 Entry - Computational Fluid Dynamics, As You Like It

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Dear Reader, 

When I first learned about computational fluid dynamics (CFD), I became enthralled by the capabilities it afforded. I was an aspiring aerospace engineer but limited by the extraordinary cost of building small airplanes and rockets, both in time and money. CFD, however, was (and is) readily accessible. I obtained a student license for popular software and was quickly able to design and test various configurations without the aforementioned constraints. Now, it is my sincere wish that all aspiring engineers become familiar with this resource and see the glory that it provides — so, I have made this explainer accessible to those who are interested in engineering, regardless of the level of previous knowledge they may have. I hope you enjoy it, and that you are able to design something new and cool. At least, if you feel lost or aimless in your differential equations, linear algebra, or fluid dynamics class, you could find benefit or recentering from this article, to help drive you forth to learn more. Maybe this will inspire you to build a car, a plane, or a rocket. Perhaps, one day, you’ll become an F1 engineer, a rocket scientist, or build the next supersonic jumbo jet. If even one person who reads this finds joy in the potential capabilities of engineering, then I will consider this endeavor to be a success. 

Note: Even if you're a higher-level reader, I recommend that you read earlier levels first in order to experience the joy of seeing the evolution of the theory from basic to advanced, and contextualize more complicated concepts.

Today, we've journeyed from stadium crowds to the volume integrals that discretize the Navier-Stokes equations. Whatever level you read, I hope you now understand how CFD works. You now know what is happening as the progress bar crawls across the screen, as thousands or millions of cells negotiate with their neighbors for mass, momentum, and energy. This is the exact theory that your favorite F1 team uses to make their cars even just 0.1 seconds faster,  Airbus uses to make their planes more efficient, or Toyota uses to make their cars go further per gallon. You can learn to use it too - downloading OpenFOAM (https://openfoam.com) is an easy way to learn the basics of CFD and further develop and understand the theory behind it. You can also try out the basic CFD code I included on this website below, using the buttons and sliders. (Some parts are a bit buggy, if something glitches, just reload the page or download the Python code.) That rocket you wanted to launch, that plane you wanted to fly, that car you wanted to drive doesn't have to remain a dream. You have the knowledge and the tools now. I hope you try it out, and I hope that my explainer today democratizes engineering for you as it did for me.  My only question is, what will you simulate first?