Bumpy drives may soon be history

Washington, July 8 (ANI): Bumpy drives may soon be history, with an international team of researchers gaining fresh insights into the ripples on loose surfaces-sand or gravel or snow-that make driving a very shaky experience.

The research team including experts from Canada, France, and the United Kingdom have basically recreated this "washboard" phenomenon in the lab with surprising results.

They have found that ripples appear even when the springy suspension of the car and the rolling shape of the wheel are eliminated.

According to the researchers, the discovery may smooth the way to designing improved suspension systems that eliminate the bumpy ride.

"The hopping of the wheel over the ripples turns out to be mathematically similar to skipping a stone over water," says University of Toronto physicist, Stephen Morris, a member of the research team.

"To understand the washboard road effect, we tried to find the simplest instance of it, he explains. We built lab experiments in which we replaced the wheel with a suspension rolling over a road with a simple inclined plow blade, without any spring or suspension, dragging over a bed of dry sand. Ripples appear when the plow moves above a certain threshold speed.

"We analysed this threshold speed theoretically and found a connection to the physics of stone skipping. A skipping stone needs to go above a specific speed in order to develop enough force to be thrown off the surface of the water. A washboarding plow is quite similar; the main difference is that the sandy surface 'remembers' its shape on later passes of the blade, amplifying the effect," Morris adds.

Familiar to drivers of back country roads the world over, washboard road also appears in some other surprising places in nature and technology.

Just about any time a malleable surface is acted upon by a sideways force, you will get ripples.

The researchers say that washboard road is analogous to the little ripples that form on wind- or water-driven sand at the beach, and to the moguls which develop on ski hills.

According to them, motocross bikes and snowmobiles also make ripples.

They further state that washboard can also cause tiny bumps on steel railway tracks, and even the read head in a hard disk can sometimes hop along the surface of the disk to make a washboard pattern.

A research article describing their findings has been published in the journal Physical Review E. (ANI)