Most fluid flows at human scales and at moderate speeds (> 1 m/s) reach Reynolds numbers of at least 10⁴ or higher, causing even tiny disturbances to amplify and drive the flow toward turbulence. Turbulence is a broadband, continuum phenomenon: turbulent eddies of vastly different time and length scales enhance the mixing and transport of momentum, heat, and scalars through chaotic fluctuations. These processes critically affect system performance, influencing drag/lift/noise/vibration on lifting surfaces, energy-conversion efficiency (e.g., wind turbines and combustion engines), and the spread of pollutants or airborne diseases.

In this talk, I will highlight computational research from my group on modeling wall-bounded turbulent flows, analyzing laminar–turbulent transition through stability theory, and developing Lagrangian approaches for turbulent momentum transport. I will first summarize my work on wall-modeled large-eddy simulation (WMLES), a leading technique for affordable, scale-resolving simulations of wall turbulence, applied to both canonical configurations (flat plates, channels) and complex geometries (aircraft and atmospheric flows over sand dunes). I will then discuss the relevance of boundary layers with intrinsic three-dimensionality in these complex flows and present our recent efforts to understand turbulence transition originating from a three-dimensional base flow. Lastly, I will showcase our ongoing research on extracting Lagrangian information in a fully Eulerian manner—without particle tracking—which has revealed previously unseen flow phenomena that warrant further investigation.