Experimental study of a three dimensional cylinder-filament system.

Sammanfattning: Can plant seeds disperse with- out wind? This can be said to be the question that sparked this project. Plants and animals use all kinds of appendages to aid their locomotion, e.g. feathers, hairs or fins. Some of these appendages may be used for a type of passive locomotion that utilizes the separated flow around the main body, without the need for additional energy expenditure. This report details the investigation of a three dimensional cylinder of diameter D, with a lament of length L attached to the rear. The cylinder is placed in a uniform flow and the mean position of the lament is measured for various lengths. It is found that long ( L/D > 6) and short (L/D < 2) filaments tend to align with the flow. Where for intermediate lament lengths (2 < L/D < 6) the filament lie down on the cylinder and is aligned with the cylinder axis.