This is your senior project, not your scientific contribution to model aircraft world. It is also not a poularity contest. Pick something that you can succeed in the process of doing the work that makes a succesful project. Your grade will depend on your success in the process of doing the project, not the perceived value of the results.

Don't get me wrong, I would love to see CFD models of airstream from a propellor in relation our aircraft, but you really need to consider the complexity of propellor dynamics that would be involved with modelling it and make sure it is within your capabilities to do.

Professors love to teach lesson, and if you go to a professor with a project that is amibitious beyond your capability/understanding, he/she will be more than happy to oblige you. Whether you bite off more than you can chew and struggle through it, or you pick something reasonable, they know that either way a lesson will have been learned...

Richard