The Role of the Large-Scale Structures in Turbulent Wall Jets

The development of the large-scale turbulent
structures is experimentally investigated in both
impinging jets and three-dimensional wall jets. An
azimuthal decomposition of the fluctuating wall
pressure in the impinging jet revealed the presence
of large-scale ring structures; however, these ring
structures did not appear to impact the wall
concentrically. The
development
of three-dimensional wall jets exiting rectangular
channels with aspect-ratios from 1 to 8 was
investigated using the turbulent velocity and
measurements of the fluctuating wall pressure. The
development was found to be delayed by increasing the
channel aspect-ratio, but the length-scales in the
different jets could be collapsed by scaling the
streamwise coordinate by the square root of the
channel cross-sectional area and normalizing by the
size of the channel. Pressure-velocity correlations
indicate that the large-scale structures in these
flows are strongly asymmetric.

Autorentext

The author completed hisundergraduate, Masters and Doctoral degrees in MechanicalEngineering at McMaster University in Hamilton, Ontario, Canada.Hall is now a faculty member in Mechanical Engineering at theUniversity of New Brunswick in Fredericton, New Brunswick.

Klappentext

The development of the large-scale turbulentstructures is experimentally investigated in bothimpinging jets and three-dimensional wall jets. Anazimuthal decomposition of the fluctuating wallpressure in the impinging jet revealed the presenceof large-scale ring structures; however, these ringstructures did not appear to impact the wallconcentrically. Thedevelopmentof three-dimensional wall jets exiting rectangularchannels with aspect-ratios from 1 to 8 wasinvestigated using the turbulent velocity andmeasurements of the fluctuating wall pressure. Thedevelopment was found to be delayed by increasing thechannel aspect-ratio, but the length-scales in thedifferent jets could be collapsed by scaling thestreamwise coordinate by the square root of thechannel cross-sectional area and normalizing by thesize of the channel. Pressure-velocity correlationsindicate that the large-scale structures in theseflows are strongly asymmetric.