Inspired by a discussion with Olav and the page Nakka Rocketry, this is a sketch at how to calculate a graph of acceleration over time for a given cross section of propellant. The simulation works by burning the pixels that are not enclosed by propellant or unburnable material. This repeats over and over until every pixel has burned, and produces a graph over acceleration. As can be seen from the tubular cross-section, this is not very accurate - the shape produced in the end is not a circle, but a box with rounded corners. This is unavoidable with the pixel approach.
Send feedback and fancy cross-sections to the email at the bottom.