Computational Fluid Dynamics (CFD) has become a widely used tool in industry as the cost for simulations is usually lower than the cost for multiple experiments. CFD is an effective tool for comparing design alternatives, investigating specific flow features and in some cases it may be the only feasible option for studying engineering flows. As a result, the demand for mechanical engineers with CFD skills keeps increasing. Nevertheless CFD is still not adequately presented in undergraduate engineering curricula, which can lead to expensive mistakes, if for example it is relied on without understanding its limitations. One excellent platform for CFD, which can be introduced to fluid mechanics classes, is the open-source environment OpenFOAM, which is widely used in both academia and industry. In addition to being open-source, OpenFOAM code can be viewed and modified by the user, and a wide range of modules for OpenFOAM are available with new modules being developed constantly. One major disadvantage, however, is that OpenFOAM has a rather steep learning curve and although there are many resources available online, it is difficult to find short introductory courses. A tutorial was developed to provide a brief introduction to OpenFOAM and allow the students to perform simple simulations. Upon completing the tutorial, the students can build their own simulations. The tutorial covers geometry, mesh, boundary and initial conditions, solvers, schemes, post processing, and some additional features, such as shell scripts and parallel processing. A large portion of the tutorial is devoted to the geometry and mesh generation as this is one of the more challenging aspects of OpenFOAM compared to conventional graphical user interface CFD packages. Nevertheless, the students are exposed to the importance of properly setting the other simulation parameters through simple examples — e.g., comparing 2D channel flow simulations using potential flow and using turbulence modeling. One crucial aspect of the tutorial is that students are encouraged to experiment with deliberate modifications of the simulations to experience and understand how some of them do not provide reasonable results. Although the tutorial is rather brief and does not cover the topics in much detail, it aims to familiarize students with the basics of OpenFOAM, so that they can better understand other relevant resources. The OpenFOAM tutorial offers an alternative introduction to CFD compared to commercial CFD packages, which may not be readily available. The tutorial has already been utilized for three consecutive years at the University of New Hampshire, mostly by undergraduate students who worked/are working on senior projects involving CFD. The feedback has been generally positive.