The wakes of swimming fin are revealed through the flow visualization technique developed herein. A flow visualization technique using dilute solutions of tobacco mosaic virus (TMV) is described. Rod-shaped TMV-particles align with shear, an effect that produces a luminous interference pattern when the TMV solution is viewed between crossed polarizers. Attractive features of this technique are that it is both transparent to the naked eye and benign to fish. We use it here to visualize the evolution and decay of the flows that they produce. We also report that dilute solutions of Kalliroscope are moderately birefringent and so may similarly be used for qualitative in situ flow visualizations.
See paper here: Hu, Goreau and Bush (2008)
Images presented here: Hu, Goreau & Bush, Gallery of Fluid Motion (2005) .
“As I see it, life is an effort to grip before they slip through one’s fingers and slide into oblivion, the startling, the ghastly or the blindingly exquisite fish of the imagination before they whip away on the endless current and are lost for ever in oblivion’s black ocean.” — Mervyn Peake