For the type of stuff they do at Carderock, I'd say experiments are way better. Maneuver dynamics is really, really hard to do, as the time scales of the probl

For the type of stuff they do at Carderock, I'd say experiments are way better. Maneuver dynamics is really, really hard to do, as the time scales of the problem are long (ships turn on the order of a minute), something very challenging for CFD to accurately represent. Also, accurate free surface liquid dynamics is really damn hard to do, and I'd be skeptical of of most model's accuracy. I certainly wouldn't make billion dollar decisions on it. In aerodynamics, which has had much more time and money invested, CFD can almost completely replace the wind tunnel, but only for aerodynamics problems we understand (ie wings, fairings, nacelles, turbine blades, backward facing steps, etc). As soon as you leave the validated/understood world, CFD becomes a tool used to augment the designer's intuitions, with the wind tunnel providing an essential ground truth. Fluid dynamics is the business of predicting complex nonlinearities to a few %, and imo, complex nonlinear models are only useful when validated. It's telling that when they debated building the DDG1000 they built a 1/4 scale ship: http://upload.wikimedia.org/wikipedia/commons/4/4a/Advanced_Electric_Ship_Demonstrator.jpg http://upload.wikimedia.org/wikipedia/commons/4/4a/Advanced_...