Tripping Down the Streets of the City

New “Wind Lens” Turbine Magnifies Wind For Increased Power, Reduced Noise

There are a number of stories about this, and for most of them the technical explanation starts and ends with “The structure works similarly to a magnifying glass that intensifies light from the sun — except in this case, the lens intensifies wind flow” or something similar. Which is really frustrating. This story doesn’t, and even provides a link to the university web site, so perhaps we can glean additional information from that.

OK, it looks like this “lens” is a venturi of sorts. I’m neither a fluid mechanic nor an aeronautical engineer; I imagine the compressibility of the air makes this a little different for air than for water. But when you restrict the area of flow, the speed increases. Put another way, by funneling/focusing you increase the energy density of the air, so more energy is present within the area of the turbine and you can extract more energy without making the blades bigger. That much I get. I’m not sure if this accounts for all of the increased efficiency or if there are other effects as well, like improved efficiency by generally having higher speeds. It certainly doesn’t look like you are tripling the capture area from the pictures.

The stories tout this as being great, but I notice that the turbines are ~1 kW, as opposed to commercial turbines which are MW-ish beasts, and the researchers do not say how far this effect will scale up, and in fact caution that it will not. The bits about how these might be less objectionable on aesthetic grounds don’t sway me — there’s no justification that these will look pretty to those who disapprove of regular turbines. So I’m not seeing these as “farms” and >100 m diameters would seem to exclude them as being put up in your yard.

Can I Get Insurance for it?

Secrets of the gecko foot help robot climb

A Stanford mechanical engineer is using the biology of a gecko’s sticky foot to create a robot that climbs. In the same way the small reptile can scale a wall of slick glass, the Stickybot can climb smooth surfaces with feet modeled on the intricate design of gecko toes.

If you watch the video, you might notice that they appear to have edited out a section discussing the need for a tail — the only kept the part when they added the tail and tell us the “now stickybot can climb.” It’s too bad, because I think there’s a bit of interesting physics there. It’s mentioned briefly in this video, where you can see a real gecko with its tail pressing against a surface, the hind legs acting as a fulcrum, so that it can move its upper body back toward the surface.