Observations of flow repeatability and secondary circulation in an oscillating grid-stirred tank

An oscillating grid-stirred tank was studied for flow repeatability and the existence of secondary circulations. For the particular tank studied, results indicate that mean flow values may vary by up to 25% and turbulent fluctuations may vary by up to 15% from one run to another. This result was observed to exhibit a potential grid geometry dependence. More importantly, there is evidence of significant flow field sensitivity to initial conditions. Particle image velocimetry results were used to reveal secondary mean flows in the grid-stirred tank. Because these characteristics are believed to be intrinsic to grid-stirred tanks, studies using such tanks must recognize and consider these effects. (C) 2004 American Institute of Physics.