Water Polygons and Polyhedra!

9 02 2007

FLUID POLYGONS AND POLYHEDRA

Figure 1. Figure 2. Figure 3.

Figure 4. Figure 5. Figure 6.
When a vertical water jet strikes a circular horizontal impactor, the water is deflected into a horizontal sheet. At sufficiently high speeds, the flow results in a circular water sheet, whose radius is set by a balance between inertial and curvature forces. At lower speeds, the sheet sags significantly under the influence of gravity, and may close, giving rise to a water bell (Figure 1). We have conducted a series of experiments in order to investigate the influence of increasing fluid viscosity on fluid sheets and bells.
The circular fluid sheets are marked by an axisymmetry-breaking instability that results in polygonal structures (Figure 2). Fluid streams from the sheet, into then along the rim, and finally streams from the corners of the polygon. In certain parameter regimes, the streams emerging from the corners take the form of a linked chain (Figure 3). The minimum number of sides observed on the polygons was four. By deflecting the sheet from the horizontal, one may produce sagging structures ressembling fluid umbrellas (Figure 4) or fluid parasols (Figure 5). Axisymmetry is also broken in the fluid bells, which assume the form of polyhedra (Figure 6).

This series of photos appears in Buckingham & Bush (2001, Phys. Fluids, Gallery of Fluid Motion).
The results of a combined theoretical and experimental investigation of the polygonal sheets is under review.


Actions

Information

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s




%d bloggers like this: