Eleven types of single circular biplane grids with different diameter (d) a
nd mesh (M) were vertically and constantly oscillated inside a 2 L, square
jar. The velocity components were measured using a 2D laser doppler anemome
ter. The average root-mean-square turbulent velocity q' values were found t
o be relatively constant at both vertical and horizontal points of measurem
ent-a condition that could not be achieved in the case of impeller mixing.
Since the mixing intensity was uniform within the jar, the average volume v
elocity gradient (G) over bar could be applied as the surrogate mixing inte
nsity parameter. It was also found that q' was linearly related to the vert
ical grid speed and grid physical characteristics, indicating that the mixi
ng was easily controlled, The macro length scale (L) was calculated and was
found to be constant and proportional to d or M, as it should be in the ca
se of turbulent mixing. This study shows the potential of grids as the mixi
ng devices that can be expected to produce an optimum mixing environment fo
r the flocculation process.