Most flows we encounter on a daily basis are turbulent. Ocean waves, oil transported in pipelines, and exhaust gases from the catalytic converter of an automobile are few examples of turbulent flow. The turbulent flow is chaotic where the fluid undergoes irregular fluctuations in both time and space. These fluctuations cause enhanced mixing of the fluid, increasing the pressure drop and heat transfer. The fluctuations in the flow are caused by swirling flow structures, or eddies, that can exist in a wide range of sizes in the flow — some small, that are homogeneous and independent, and others large, governed by the flow field. To study the effect of turbulence, the transport phenomena associated with all these vortices need to be resolved, which is not always possible due to computational hardware limitations. To mitigate this, the concept of time-averaging is introduced and a set of equations, called the Reynolds Averaging Navier-Stokes (RANS), are developed.

This SimCafe Fluids Course was developed by Dr. Rajesh Bhaskaran, Swanson Director of Engineering Simulation at Cornell University, in partnership with Ansys, and was last modified by Sebastien Frances Zhu. In this course, we will learn to model the turbulent flow inside a pipe using the Reynolds Averaged Navier-Stokes (RANS) approach by following the end-to-end workflow in Ansys Workbench.

For more ways to learn, check out the Cornell edX course, A Hands-on Introduction to Engineering Simulations at __ansys.com/cornell.__

Cornell University also offers a *Fluid Dynamics Simulations Using Ansys* online certificate authored by Dr. Rajesh Bhaskaran. Learn more here: __https://ecornell.cornell.edu/fluiddynamics__