Antonia, R. A.
The interaction between the opposite shear layers in a fully developed turbulentduct flow has been examined with the use of an array of X probes deployed in the plane of mean shear. This array provides simultaneous information on the turbulence characteristics of the shear layers on either side of the centerline. The application of a uv quadrant analysis to the data indicates that quadrant 2 events on one side of the centerline can almost reach the opposite wall. The extent of the intrusion across the centerline increases as the Reynolds numberdecreases. The contribution from events in quadrant 2 to the Reynolds shear stress is smaller in the duct than in a boundary layer, reflecting the mutually inhibiting effect of flow structures associated with the opposite shear layers. In the central region of the duct, spectra of the lateral velocity fluctuation vsuggest that the average wavelength of the organized motion is about 3.2h, where h is the duct half‐width. This wavelength is also evident in v‐correlation contours and seems independent of the Reynolds number.
Antonia, R. A.
The interaction between the opposite shear layers in a fully developed turbulentduct flow has been examined with the use of an array of X probes deployed in the plane of mean shear. This array provides simultaneous information on the turbulence characteristics of the shear layers on either side of the centerline. The application of a uv quadrant analysis to the data indicates that quadrant 2 events on one side of the centerline can almost reach the opposite wall. The extent of the intrusion across the centerline increases as the Reynolds numberdecreases. The contribution from events in quadrant 2 to the Reynolds shear stress is smaller in the duct than in a boundary layer, reflecting the mutually inhibiting effect of flow structures associated with the opposite shear layers. In the central region of the duct, spectra of the lateral velocity fluctuation vsuggest that the average wavelength of the organized motion is about 3.2h, where h is the duct half‐width. This wavelength is also evident in v‐correlation contours and seems independent of the Reynolds number.