Separated shear layer of blunt circular cylinder has been experimental
ly investigated for the Reynolds numbers (based on the diameter) rangi
ng from 2.8 x 10(3) to 1.0 x 10(5), with emphasis on evolution of sepa
rated shear layer, its structure and distribution of Reynolds shear st
ress and turbulence kinetic energy. The results demonstrate that lamin
ar separated shear layer experiences 2 similar to 3 times vortex mergi
ng before it reattaches, and turbulence separated shear layer takes 5
similar to 6 times vortex merging. In addition, relationship between d
imensionless initial frequencies of K-H instability and Reynolds numbe
rs is identified, and reasons for the decay of turbulence kinetic ener
gy and Reynolds shear stress in reattachment region are discussed.