Application of a modified k-ε model to the prediction of aerodynamic characteristics of rectangular cross-section cylinders

Aerodynamic characteristics of rectangular cylinders of infinite length and various breadth-to-depth ratios ranging from BID = 0.6 to 8.0 were investigated numerically by a two-layer k-epsilon model with a modified k-production term. Although the numerical method is two-dimensional (2-D), a physically reasonable smooth, periodic vortex shedding was obtained, even in the range of high Reynolds number. This kind of behaviour cannot normally be simulated by ordinary 2-D analyses which do not incorporate a turbulence model. Various typical aerodynamic features were successfully obtained, particularly including the discontinuity in Strouhal number at the critical section of BID = 2.8 and 6.0. Also, drag coefficients and distributions of mean surface pressure were in good agreement with results of experiments and 3-D analyses for the range of BID ratios. However, as regards the prediction of pressure and force fluctuations, since the currently available Reynolds-Averaged Navier-Stokes models are able to analyse only periodic components and not stochastic components, the total fluctuations in surface pressure and aerodynamic lift force were considerably underestimated in some cases, compared with those measured in experiments and calculated from 3-D analyses. (C) 2002 Elsevier Science Ltd. All rights reserved.