Posts

Featured Post

How to Think About Car Aerodynamics: A Very, Very Basic Overview

Image
The study of aerodynamics is complicated. If anyone tries to tell you otherwise, run the other direction—it’s a sure sign they don’t know what they’re talking about.   Over the last two years especially, my thinking about aerodynamics and appreciation of its complexity has changed dramatically—a result of my going back to school to get another bachelor’s degree, this time in aerospace engineering where a good working knowledge of airflows is required and education in not just general fluid mechanics but also aircraft aerodynamic design forms a core part of the technical curriculum. I'm in the midst of my last semester now and to clarify my thinking at this point I decided to put some things in writing in the hopes they might help someone else as well as myself, specifically focused on car aerodynamics. A word of warning: I've tried to minimize the amount of math below, but some mathematical relations are unavoidable if you want to build an understanding of fluid flows. If anyth...
Post a Comment
Read more

Why Your CFD is Wrong – Part 2: Solving Mathematical Models

Image
Last time, we saw how engineers construct differential equations to describe physical phenomena such as fluid flows, representing these real things in the language of mathematics . You may have found yourself wondering, “How do we solve these?” Generally, engineers can use one of two methods. First, we can attempt to solve the equations or systems like any other math problem, the way you’re probably used to doing since as far back as you can remember. This involves manipulating the equations and transforming them using mathematical operations to arrive at an answer. We call this the analytical approach. Implementing a number of simplifying assumptions (constant density, constant pressure, no viscosity, etc.) leads to a scalar equation derived from the Navier-Stokes equations that is solvable analytically. In class last spring, we used this  “1-dimensional linear advection” equation to check the numerical solutions we developed later on.   Analytical Solutions   If we ...
Post a Comment
Read more