Figuring Out Aspects of Computational Fluid Dynamics

Computational fluid dynamics (CFD) is now a fundamental part of developing vehicles, be it for purposes of modeling combustion, HVAC systems or the body moving through the air. However, there are models and there are models, and the image shown here, with Dr. Peter Vincent of the Department of Aeronautics at Imperial College London in front of the display, is probably somewhat larger than is ordinarily the case.

“We now have a solution for an important fundamental flow problem. This means we can check empirical models of turbulence against the ‘correct’ answer, to see how well they are describing what actually happens, or if they need adjusting.”

Vincent and his colleagues A. S. Iyer, F. D. Witherden, and S. I. Chernyshenko, have done research into turbulence that allows the testing of empirical models (it is a case where the modeling is generally based on previous observations to predict what will occur). Said Vincent: “We now have a solution for an important fundamental flow problem. This means we can check empirical models of turbulence against the ‘correct’ answer, to see how well they are describing what actually happens, or if they need adjusting.”

The researchers have developed the way by which exact parameters describing how disturbance dissipates in the flow and determined requirement that empirical turbulence models must satisfy. As Professor Sergei Chernyshenko put it, “From my first days studying fluid mechanics I had some fundamental questions that I wanted to know the answers to. This was one of them, and now after 40 years I have the answer.”

The four prepared a paper published in the Journal of Fluid Mechanics. The opening summary statement is: “Eigenmodes of averaged small-amplitude perturbations to a turbulent channel flow —which is one of the most fundamental canonical flows — are identified for the first time via an extensive set of high-fidelity GPU-accelerated direct numerical simulations.” Which gives you a sense that this is not the sort of thing you’d dip into for some light reading.