Monday 21 October 2013

The tube map dynamic model

The London tube map is a strange and wonderful thing. Compared to most maps, it is not information dense. Yet it contains exactly enough information to allow passengers to easily navigate a complex system of interchanges. Compared to most maps, it is not geometrically similar. The one criteria that usually determines the usefulness of a map has been flouted: indeed a geometrically similar tube map would be more difficult to follow, and hence less useful.

The London tube map is an example of how the measure of a model's quality and information content depends on its purpose. There is no one model that is the best choice in all contexts. It is also a useful reminder that a model is distinct from the concept it represents.

Friday 11 October 2013

Why not use wavemakers?

"If you are trying to make a good wavemaker, why not use wavemakers?"

If we take the statement 'a good wave absorber is a good wave maker' to its logical conclusion, then why not consider the wavemakers in our wave tanks? Most tanks for simulating deep water waves have a series of bottom-hinged flaps, mounted on the edge of the tank.