Rectangular prisms with different depth-to-width ratios (B/D) were placed in flow fields with various turbulence intensities (T.I.) and length scales to study the unsteady structures of separated shear layers. Velocity profiles, turbulence intensity profiles, velocity gradient profiles, and wake spectra of the prisms were measured. When B/D=.4 to 1., differences between the acceleration and deceleration phases of these profiles were prominent, indicating strong vorticities especially when B/D= .6. These differences, also supported by the spectra peaks, became less obvious when B/D=2. and 3.. The approaching field T.I. had a larger effect than the length scale. Higher T.I. led to increased intensity, flow mixing, and thickness of the boundary layer, but weaker wake vorticity.
關聯:
Journal of the Chinese Institute of Engineers=中國工程學刊 26(5), pp.721-727
