(611d) Use of Comsol Multiphysics in Undergraduate Research Projects to Solve Real-Life Problems

While transport phenomena textbooks are good at presenting the fundamentals, most of the problems are one-dimensional, since that is the limit of the mathematical ability of most undergraduates. Today's students are motivated by real-life examples, but they have limited time. With the advent of sophisticated software, however, it is possible for undergraduates to solve meaningful transport and flow problems in two and three dimensions. This talk presents the methods used to introduce undergraduates to Comsol Multiphysics and the problems they solve in a research project format.

The learning occurs in three stages. First, the students learn to solve problems in their textbooks and learn to validate the solution. This gives confidence that the computer program is solving the right equations. Next, they solve more complicated 2D problems, which go beyond their textbooks by removing assumptions. In this stage, students are confronted with the necessity of translating their problem into the notation of the computer program and proving they have solved the problem correctly even though there is no analytic solution. They learn how to check their data input to the program, look for artifacts in the solution, and use mesh refinement to estimate the numerical error. They explore the many ways to analyze and view the results, from streamlines, contour plots, integrals, etc. of the dependent variables as well as derived quantities (defined in terms of the dependent variables). For example, is the total flow in equal to the total flow out? ? not a straightforward question when there are multiple inputs and outputs and the solution is numerical. The second step is illustrated in detail to show the breadth of analysis techniques.

The third stage in the learning process is to solve their research problem. Examples done during the past year are demonstrated (many suggested by research groups or companies):

Thermal field flow fractionation ? the effect of entry effects; Use of ferrofluid to remove arsenic from water supplies; Flow of viscoelastic fluids in contractions; Movement of nanoparticles in gels; Mixing of pharmaceuticals in orbital mixers and injection/remove devices; Mixing and flow in Swagelok and Circor Tech devices; Flow in expansions ? pressure drop and entry/recovery lengths; Flow of water in porous media; Perturbation method applied to the flow of a ferrofluid in an oscillating magnetic field; Hole pressure problem ? used to measure normal stresses in polymers; Calculation of vortex viscosity of ferrofluids.

Valuable features of Comsol Multiphysics include the graphical user interface, the tools for creating the geometry and internal boundaries and domains, automatic mesh generation and refinement, the ability to solve different equations on different meshes (all in the same problem), the multi-physics capability which permits addition of equations to represent additional phenomena, the ability easily to make parameters depend upon the solution, the parametric solver, and the post-processing graphical features