NUMERICAL INVESTIGATION OF FORCED TRANSITIONAL WALL JETS

摘要: Direct numerical simulations (DNS) based on the incompressible Navier-Stokes equations are employed to investigate secondary instability mechanisms in a forced transitional wall jet. Our indicate that addition commonly known two-dimensional subharmonic resonance associated with outer free shear layer region of jet, three-dimensional fundamental and resonances nearwall boundary may play role transition process as well. For example, twodimensional vortical structures near-wall can be weakened enough through moderate forcing ejection vortex pairs from into ambient fluid is prevented. Similar observations have been made large-eddy (LES) bypass where (random time) large amplitude applied. Vortical strong spanwise coherence observed but remains predominantly three-dimensional.