In considering kayak stiffness, we probably need to discriminate based on the amount of flexing. Big, structural dynamic flex like having the bow bend upward to go over a wave produces different effects than soft skin flexing around a little tiny cell of turbulence. The "dolphin skin" drag reduction mechanism is close to being rationalized. When the right set of equations are examined for the transition between laminar and turbulent flow, the solution has a vibrational component. This vibration corresponds to little "ripples" in the flow around the hull. I imagine that they are on the order of several millimeters in length. Evidently the trick with "dolphin skin" is to tune the skin response in such a way that it "feels" the pressure oscillations and responds just down-stream of the excitation in such a way as to damp the fluid vibrations. Here, the dolphin has the advantage of evolutionary development. We are stuck with some of John Winters' complex mathematics --and the conversion of the model into useful, interactive material properties. Gross structural deformations are another problem. It it interesting that stiffening a skin boat hurt its behaviour in waves. bob phillips SE Michigan where the water surface is not flowing today. *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Sat Jan 15 2000 - 08:47:35 PST
This archive was generated by hypermail 2.4.0 : Thu Aug 21 2025 - 16:30:18 PDT