Swirl flow is the primary mechanism for separation of particles in a hydrocyclone and hence influences the performance. The study of examining the basic swirl flow mechanism is accomplished by using a cylindrical apparatus with rotating lids. The upper and lower lids of the cylinder are able to rotate in the counter and clockwise direction at different angular velocities. In this study, the basic mechanisms of swirling it the laminar regime are investigated using an optically clear cylinder with rotating lids. The cylinder is filled with a liquid and the upper and lower lids of the cylinder are allowed to rotate in the clockwise and counter-clockwise directions. The induced flow is measured with a laser doppler anemometer and is compared to the velocity predictions from an in house developed software which solves the equations of motion. The results presented here constitute the first step in a series of experiments with the ultimate goal to improve the separation mechanism of hydrocyclones by means of controlling swirling flow characteristics. (c) 2007 Elsevier Ltd. All rights reserved.