Turbulence — One of Physics’ Most Important and Enduring Challenges

Research into the puzzling nature of turbulence is essential because of its impact on the flow physics of liquids and gases. It is fundamental to understanding the air surrounding a bird or an airliner, flow inside a jet engine, or the continuous flow of air around wind turbines. Greek philosopher Heraclitus defined it best when he once said: “Everything flows and nothing abides; everything gives way and nothing stays fixed.”

Turbulence simulations are particularly difficult because of the wide-range scales of motion involved. Resolving all of the scales requires very fine computational grids with billions of points that include the tiniest of scales, where viscous dissipation – the heating of the fluid due to resistance – occurs. High-performance computing suits direct numerical simulation (DNS) modeling especially well because it can advance several flow variables, including velocity and pressure, in time over billions of grid points.

Most flows in nature are turbulent; therefore understanding turbulent flows is important for achieving a sustainable planet. As computational resources become ever larger, scientists will be able to handle ever more complex turbulent flow problems that may lead to reduced fuel costs and carbon dioxide emissions. -- © i SGTW