DURHAM – University of New Hampshire professor Joseph Klewicki is working on a physics problem that could change the way airplanes and cars operate.

Even Albert Einstein considered the issue to be one of the most confounding physics questions left unanswered: How does fluid interact with a moving surface?

The question may seem simple, Klewicki said, but it is not. Figuring out the relationship between fluids, which includes water or air, among other things, could lead to advances in transportation designs for submarines to airplanes.

Klewicki recently received a $360,000 three-year Experimental Program to Stimulate Competitive Research grant, commonly known as EPSCoR, from the Defense Department, plus an additional $180,000 from UNH to study the issue.

"The problem I'm really looking at is flow over any surface," said Klewicki, a professor of mechanical engineering and the dean of UNH's College of Engineering and Physical Sciences.

For example, as a submarine travels through water, the water slides over the ship's surface. At slower speeds, the flow appears to be smooth, but as the vessel goes faster, small eddies form around the surface, creating turbulence.

The same happens for nearly every moving thing because each one travels through either water, as with submarines, or air, as with cars and airplanes.

How those eddies develop and what influences them is largely a mystery, making it hard to precisely predict the drag or noise.

Air reacts much the same way as it flows against objects, such as cars or planes, making the question even more far-reaching.

The flow over a surface is known as the boundary layer. Klewicki plans to try to chart it by taking numerous measurements from points within the layer to try to create a formula that will represent the average flow.

At work in the layer are three forces: viscosity of the fluid, the flow of the fluid and the turbulent force known as Reynolds stress. How the three interact will be a key piece of Klewicki's research and help to create the formula for the boundary layer.

Once a formula is created, Klewicki said, scientists will be able to better predict and control the boundary layer. Better interaction with fluids can lead to better design.

For example, Toyota's hybrid Prius is designed to create less drag, which means better fuel mileage.

"As we go along, I think more people would rather have a car that saves money than looks nice," Klewicki said.