1 / 13

The McEel project

The McEel project. Status and goals winter 2003-2004. Two unfamiliar environments and two approaches -. When man first tried to fly a lot of effort was put into investigating birds and bats, animals that already mastered the art. .

tatum
Download Presentation

The McEel project

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The McEel project Status and goals winter 2003-2004

  2. Two unfamiliar environments and two approaches - When man first tried to fly a lot of effort was put into investigating birds and bats, animals that already mastered the art. When man first started to make subsea vehicles they were all modifications of existing surface craft.

  3. How do these human made craft compare today- • Birds vs. Planes: • No known animal can go supersonic. • The maneuverability of modern fighter planes is impressive. • Fish vs. Submarines: • Today's submarines and AUVs are outright clumsy. • The worlds fastest fish swims at 80 knots+. • Even at this speed they turn within half a ship length. • Most fish can hover.

  4. How do fish swim? Although they are one of the older animals groups fish propulsion is still not fully understood. From an engineers point of view all fish swim by setting up backward traveling waves with increasing amplitudes. These waves generate a zigzagging train of vorticies pushing water backwards. Can this be mimicked by a man-made machine?

  5. The project aims to compare A numeric solution with an empiric one. Input from the latter will then be used to perfect the numeric one.

  6. The numeric solution. Flow around a fishlike structure will be at varying angles. Similar problem to the flow around risers or missiles. Common practice to solve these using either Morison equation or the elongated body theory. The first one assumes perpendicular flow the latter assumes tangential flow and thus they are intrinsically both wrong. As the Morison equation has been used successfully in non-perpendicular flow extensively in the offshore industry this method has been chosen for the McEel.

  7. The three forces. Morison equation describes 2 forces. Forces proportional to normal velocity and normal acceleration. In addition there is the force proportional to acceleration itself. The two acceleration forces are NOT in phase.

  8. The empiric solution. A watertight model with motors inside suggested. Discarded due to cost and complexity. Model with wire drive through a sting suggested. Two none successful models built due to small displacement and long wires. A third model with shafts running through the sting was built and has been partially successful. The main problems are the less than perfect continuous structure and problems involved in the force measurements.

  9. Todays McEel is the Mk3.

  10. The air tests. Initial tests in air for verification purposes.

  11. The bollard tests. Secondary tests were stationary bollard pull tests.

  12. The swimming tests.

  13. The swimming tests. The signal to noise ratio deteriorated when the eel started swimming. Tried to filter in frequency domain but the results are not yet satisfactory.

More Related