URBANA, Ill., Jan. 31 (UPI) -- University of Illinois scientists have solved a 73-year-old experiment involving fluid turbulence -- the last major unsolved classical physics problem.
"Turbulence is the jittery, swirling behavior of a gas or liquid when flowing next to a wall or around an obstacle," said Gustavo Gioia, a professor of theoretical and applied mechanics. He said the flows have been one of the least understood phenomena of classical physics.
In 1933, Johann Nikuradse measured the friction a fluid experiences as it's forced through a pipe at varying speeds. Nikuradse found the friction becomes smaller as the speed gets larger, but then increases at high speeds before attaining a constant value.
That mysterious behavior must be taken into account by engineers in applications ranging from airplanes to oil pipelines.
Gioia and graduate student Pinaki Chakraborty have shown how the behavior arises from fundamental properties of the way in which energy is distributed among the swirling eddies populating a turbulent flow.
"As a result of our theoretical explanation, engineers can now calculate the friction force found along rough walls, rather than rely upon a chart or table," Chakraborty said.
The research appears in the journal Physical Review Letters.