Nope! Those running Linux can download free, open-source CFD code that has a large user base in engineering and science in both commercial and academic organizations. According the the developer, the OpenFOAM code includes an extensive range of features to solve anything from complex fluid flows involving chemical reactions, turbulence and heat transfer, to solid dynamics and electromagnetics.
The developer's Web site says, "The core technology of OpenFOAM is a flexible set of efficient C++ modules. These are used to build utilities, solvers, and libraries as well as simulate specific problems in engineering mechanics, and perform pre and post-processing tasks ranging from simple data manipulations to visualization and mesh processing.
OpenFOAM comes with numerous pre-configured solvers, utilities and libraries and so can be used like any typical simulation package. However, it is open, not only in terms of source code, but also in its structure and hierarchical design, so that its solvers, utilities and libraries are fully extensible.
OpenFOAM uses finite volume numerics to solve systems of PDEs ascribed on any 3D unstructured mesh of polyhedral cells. The fluid flow solvers are developed within a robust, implicit, pressure-velocity, iterative solution framework, although alternative techniques are applied to other continuum mechanics solvers.