Computational modeling of turbulent mixing in a jet in crossflow

• The turbulent mixing in a jet in crossflow was studied.
• High-resolution measurements using PIV combined with LIF.
• Simulations ranging from steady-state RANS to sophisticated large-eddy simulation.
• Time dependent simulations are mandatory for this flow configuration.
• The increase in the computational cost translates into higher accuracy.

The jet in crossflow is a configuration of highest theoretical and practical importance, in which the turbulent mixing plays a major role. High-resolution measurements using Particle Image Velocimetry combined with Laser Induced Fluorescence have been conducted and used to validate simulations ranging from simple steady-state Reynolds-averaged Navier Stokes to sophisticated large-eddy simulation. The reasons for the erratic behavior of steady-state simulations in the given case, in which large-scale structures dominate the turbulent mixing, have been discussed. The analysis of intermittency proved to be an appropriate framework to account for the influence of these flow structures on the jet in crossflow, contributing to the explanation of the poor performance of the steady-state simulations.