BIO325H5 Lecture Notes - Lecture 5: Vortex Ring, Boundary Layer, Reynolds Number
Document Summary
The quote below comes from nature"s promotion essay (ed yong) of contained articles (he is referring to gemmell2013). They contract their umbrella-shaped bells, [and] create two vortex rings doughnuts of water that are continuously rolling into themselves. The creature sheds the first ring in its wake, propelling itself forward. As the bell relaxes, the second vortex ring rolls under it and starts to spin faster. This sucks in water which pushes up against the centre of the jellyfish and gives it a secondary boost the two vortices spin in opposite directions, one clockwise and one counterclockwise. From abstract: velocity profiles around larvae show that the body is in the boundary layer. Longitudinal twisting and yawing [turn to side] of the larval body places one labral fan closer to the substrate, the other near the top (or beyond?) of the boundary layer. Notice the body twist reflected in the nerve cord illustration (next slide).
