![Simulation of the compression stroke of an internal combustion engine](/sites/default/files/styles/965x543/public/2020-07/16x9_Nek_Image1x.jpg?itok=BC2_22zR)
Snapshot from a direct numerical simulation of the compression stroke of an internal combustion engine. During a compression stroke, the piston moves from the bottom-most to top-most position. As the piston moves up, the fluid motion inside the combustion chamber of the engine becomes even more turbulent. (Image: Argonne National Laboratory)