Diffusion is a process resulting from the movement of a substance from an area of high concentration to an area of low concentration. It is completely driven by a concentration gradient. A gas held in a container is a good example of diffusion. These fluid particles are continuously colliding with each other and with the walls of the container. Eventually, these gas particles spread to occupy the entire volume of the container in which they are held. Diffusion occurs on its own and does not require any external stirring, or shaking. The smell of incense sticks or diffusers filling up a room full of still air is a good example of diffusion. Another example is heat conduction in solids and fluids which involves thermal energy transported, or diffused, from higher to lower temperatures. This SimCafe course was developed by Rajesh Bhaskaran, Swanson Director of Engineering Simulation at Cornell University and Keith Alexander Works, in partnership with Ansys. It serves as an e-learning resource to integrate industry-standard simulation tools into courses and provides a resource for supplementary learning outside the classroom. In this tutorial, we will learn to model a three-dimensional diffusion problem in Ansys Fluent and compare the obtained numerical solution with the analytical result.
For more ways to learn, check out the Cornell edX course, A Hands-on Introduction to Engineering Simulations at ansys.com/cornell.