Abstract
The present paper deals with the two-dimensional flow field around a square cylinder moving slowly with a constant velocity along the central line of channel. The effects of the channel side-wall and the fluid elasticity to the flow field were studied by the flow visualization and the numerical analysis. The expansion of streamlines in the vicinity of the square cylinder is suppressed by the approach of the channel side-wall and the length of twin-vortices in the rear of square cylinder decreases with a decrease of the ratio of the channel breadth to the side length of square cylinder. The fluid elasticity in viscoelastic fluids suppresses the expansion of streamlines in the rear part of the square cylinder and makes rear twin-vortices smaller. Besides, computational experiments based on Maxwell model were carried out in the ranges of 10-50 of Reynolds number and 0-0.10 of Weissenberg number. It was shown that the length of rear twin-vortices increased with an increase of Reynolds number and decreased with an increase of Weissenberg number.
