Builders' Forum Archives
Re: cartopping long boats
Posted by Camper on May 9, 2007
Laszlo gotcha on this one, Jon. He was just waiting for one of us to say that.
Truth is, in subsonic aerodynamics problems--like the present one, of the kayak flying along the highway with a minivan in its talons--air is considered incompressible as a simplifying approximation, one that works very nicely.
I didn't believe it either at first. But I have been pondering it night and day for a few years. Ever since I read "basic aerodynamics for dummies" on the web somewhere.
And I have finally had to admit that these scientist types got it right. If one of those cubes full of air that they always show in the text books DOES get denser for even a moment, that density variation leaves the building, and darn quick. At 760 miles/hr in fact.
I am now ready to find something else to think about, or barring that, to finish the Sharpie.
I add that because this is a boatbuilding forum and I want to stay on topic.
In Response to: Re: cartopping long boats by Jon T on May 9, 2007