Application of two-dimensional orthogonal wavelets to multiresolution image analysis of a turbulent jet

This paper develops an application of tno-dimensional orthogonal wavelets t o turbulence for the identification of multiresolution turbulent structures and coherent structures. The digital imagine slice photographs of a turbul ent jet in a far field with Re congruent to 4.5 x 10(3) and 9.0 x 10(3) are respectively decomposed into six image components with different broader s cales by wavelet multiresolution analysis. These image components provide v isualized information on the multi-scale structures in a turbulent jet. It was found that the edges of the vortices at different resolutions or scales and the coherent structure might be easily extracted. In this problem, thr ee types of image structure. namely the targe-scale structure near the cent er of;he jet. coherent structure in the shear layer, and the small-scale vo rtices throughout the entire flow held, which dominate the turbulent struct ure, were easily extracted. By increasing the Reynolds number, the large-sc ale structure becomes weaker, and the scales of active vortices and coheren t structure decrease.