The role of turbulent bursts in particle re-entrainment in aqueous systems

Abstract An experimental investigation is reported on the interaction between turbulent-burst activity and deposited particles within the viscous sublayer of a liquid flowing, under turbulent conditions, across a solid surface. Microglass and polystyrene dvb spherical particles were carefully laid down on the surface such that the average particle layer was no more than a monolayer thick, and therefore the particles were completely submerged within the viscous boundary layer. The burst—particle interactions were recorded within an experimental flow range of 0.2–0.5 m/s, covering Reynolds numbers of 17,000–47,000 using high-speed photography and a dual laser beam technique. The results suggest that turbulent-burst activity is insignificant in re-entrainment of deposited particles completely submerged within the viscous layer. This is in disagreement with the previous hypothesis that turbulent bursts are responsible for the removal mechanism.

[1]  S. Friedlander,et al.  Deposition of Suspended Particles from Turbulent Gas Streams , 1957 .

[2]  M. E. O'Neill,et al.  A sphere in contact with a plane wall in a slow linear shear flow , 1968 .

[3]  W. G. Tiederman,et al.  Flow visualization of the near-wall region in a drag-reducing channel flow , 1972, Journal of Fluid Mechanics.

[4]  Stephen J. Kline,et al.  The production of turbulence near a smooth wall in a turbulent boundary layer , 1971, Journal of Fluid Mechanics.

[5]  J. W. Cleaver,et al.  The effect of re-entrainment on particle deposition , 1976 .

[6]  B. Mutlu Sumer,et al.  Particle motions near the bottom in turbulent flow in an open channel. Part 2 , 1978 .

[7]  R. Brodkey,et al.  A visual investigation of the wall region in turbulent flow , 1969, Journal of Fluid Mechanics.

[8]  Benjamin Y. H. Liu,et al.  Aerosol deposition in turbulent pipe flow , 1974 .

[9]  G. Sehmel,et al.  Particle deposition from turbulent air flow , 1970 .

[10]  W. G. Tiederman,et al.  Spatial structure of the viscous sublayer in drag‐reducing channel flows , 1975 .

[11]  B. Yates,et al.  Mechanism of detachment of colloidal particles from a flat substrate in a turbulent flow , 1973 .

[12]  S. J. Kline,et al.  Combined dye-streak and hydrogen-bubble visual observations of a turbulent boundary layer , 1974, Journal of Fluid Mechanics.

[13]  P. Saffman.  The lift on a small sphere in a slow shear flow , 1965, Journal of Fluid Mechanics.

[14]  S. K. Beal,et al.  Deposition of Particles in Turbulent Flow on Channel or Pipe Walls , 1970 .

[15]  M Phillips,et al.  A force balance model for particle entrainment into a fluid stream , 1980 .

[16]  Norman Epstein,et al.  FOULING IN HEAT EXCHANGERS , 1978 .

[17]  Robert S. Brodkey,et al.  A stereoscopic visual study of coherent structures in turbulent shear flow , 1978, Journal of Fluid Mechanics.

[18]  B. Yates,et al.  A sub layer model for the deposition of particles from a turbulent flow , 1975 .