不安定な縦渦と混合促進制御へのその応用について

抄録

We propose unstable streamwise vortices for use in turbulence control, in particular, the super-sonic mixing enhancement for future Scramjet engines. Although their streamwise vorticity is axisymmetric, it exists over an annular region only. Thus the vortex may undergo "inflectional instability" like low-speed mixing layers. Here, we studied the instability characteristics of the proposed vortex placed in a uniform supersonic flow at a Mach number of 2.4 through conducting numerical simulations on the basis of 2D compressible N-S equations and the inviscid stability analysis for the corresponding incompressible flow. Demonstrating the behavior of violent inflectional instability at the linear and nonlinear stages, we discuss the proposed streamwise vortices as a powerful means of mixing enhancement.