Kinetic sculpture

Rheoscopic Gear Train

A self-sustaining sculpture: rheoscopic fluid in rotating cylinders, driven by a 3D-printed gear train, after Paul Matisse's Kalliroscope.

CourseENGN 1350: Art Fluid Mechanics, Brown University

TeamSofia Gilroy, Kiara Vong, Himanssh Pettie, Lucian Sharpe

Advised byProf. Roberto Zenit

Figures8

Kinetic sculpture

Context

Rheoscopic fluid is water with microscopic mica flakes suspended in it. The flakes are flat and reflective and they orient along the flow direction, the way logs do going down a river, so internal currents become visible without introducing any dye or tracer.

The brief was a lasting, self-sustaining piece, after Paul Matisse's Kalliroscope. Rather than photograph a flow once, build something that keeps producing one.

Kinetic sculpture

Method

Rheoscopic fluid sealed into rotating cylinders, driven by a 3D-printed gear train. CAD first, then printing, then tuning the gear ratio against the flow it produced, since the rotation rate is what decides whether what you see reads as laminar or as turbulent.

The no-slip boundary condition is the actual subject. Fluid touching the wall moves with the wall, fluid at the centre lags behind, and the shear between the two is what the flakes draw for you. The patterns it settles into look a great deal like the banding in the atmosphere of a gas giant, for the same reason.

Kinetic sculpture

Selected results

The piece, running — Mica flakes suspended in water. They orient along the flow direction the way logs do in a river, so the currents inside the cylinder become visible without any dye.

Cylinder detail — The no-slip condition is the whole subject: fluid at the wall moves with the wall, fluid at the centre lags, and the shear between them is what the flakes draw.

Gear housing — 3D-printed drive, printed in place. The gearing sets the rotation rate, which sets whether the flow reads as laminar or turbulent.

CAD — The assembly before it was anything physical.

Drive train — Tooth count worked backwards from the flow we wanted to see.

Flow study — Testing rotation rates against the pattern they produce.

Flow study, II — Faster. The transition point is sharp and repeatable.

On the bench — Mid-build, with the fluid mixed and not yet sealed in.