"Fluid flow control with transformational media"

http://arxiv.org/PS_cache/arxiv/pdf/1106/1106.2282v2.pdf

Have any of you read the above new paper?

This sounds interesting but the physics is above my pay grade.

 

Think of a slab sided catamaran with convex inner hull surfaces and propulsion distributed along the tunnel so that the water is accelerated enough cancel any pressure being caused by the hulls motion. Pressure sensors can quickly respond to changing conditions. Tilting the slipsteam of a waterjet downwards is one response possibility. You can not only mitigate induced waves, you can flatten the seaway inside the tunnel a bit as well. There are scads of old patents that seem to revolve around this idea. Have never seen any test data though.

Ok, I read the paper. They are basically saying the same thing. By carefully distributing some propulsion and diffusion around an object, the flow outside the area you are fiddling with is unaffected by the passing of the solid object. What they don't address is the propulsive efficiency of such an effort. If you are primarily concerned with satelites tracking ships' wakes, it could be interesting. They've done a hell of a job of obfuscating some not that difficult math. They came at it from a previously solved electromagnetic cloaking problem (which really is a ***** given the properties of available materials). Years ago I did something similar. I wanted to cancel out the wake of oncoming or passing semis on each others' trailers. Same basic problem but it was the effect of other guys' wake I was trying to get rid of, not my own. It takes a lot less power to occasionally cancel each others wake than for everone to cancel their own all the time. The usefulness of the model mostly relates to making guesses about how a control system would be set up for a mechanism that consists of just a few parts.