Spanwise length effects on three-dimensional modelling of flow over a circular cylinder

In this study, both the two-dimensional (2-D) and three-dimensional (3-D) v ortex shedding flows around a circular cylinder are solved using a finite d ifference method. Numerical experiments are carried out to investigate the spanwise length effects on the prediction of global parameters and the near -wake flow field. The calculated Reynolds number is 1000. The results indic ate clearly that the 2-D simulation gives inaccurate predictions at the pre sent Reynolds number. The predictions are significantly improved in 3-D sim ulations, but inaccuracies may also occur if the spanwise length is set too small. Good agreement with experimental data can be achieved with spanwise lengths above twice the cylinder diameters. (C) 2001 Elsevier Science B.V. All rights reserved.