Mechanical engineering professor finds new way to predict turbulence

Researchers at Johns Hopkins University in Baltimore have discovered a new mathematical formula for describing turbulent flow. The university says the formula could lead to more precise computer models for the phenomenon, which affects the movement of pollutants, and plays a role in the way chemicals mix and combustion engines perform.
Turbulence is the chaotic flow of a gas or liquid in which parts of the current curl into irregular, ever smaller, tight eddies. Scientists cannot predict easily how a turbulent flow will behave.
Charles Meneveau, a professor of mechanical engineering at Johns Hopkins, together with Yi Li, a doctoral student in the department, unveiled their formula called the “advected delta-vee equation” in the October 14 issue of the journal Physical Review Letters.
The characteristic of intermittency has been difficult to include in computer models of turbulence because it numerically requires a huge number of calculations and a mammoth amount of computing power.
Meneveau, who is also director of the Center for Environmental and Applied Fluid Mechanics at Johns Hopkins, said “this equation gives us a mathematical shortcut to describe a complex characteristic of turbulence called intermittency. It solves just one piece of the overall turbulence puzzle, but it’s a very important piece.”
Meneveau and Li devised their calculation shortcut by tracking two particles as they move with a turbulent flow. The resulting equation gave them a tool to predict intermittency by merely solving this simple equation rather than having to solve complicated computer models of turbulence.
The professor and his students have been conducting their measurements in a wind tunnel located on the Homewood campus of Johns Hopkins.