Numerical simulation of the wake flow behind trapezoidal bluff bodies

Two-dimensional numerical simulations of the Bernard-von Karman hydrodynami c instability behind trapezoidal bluff bodies has been studied using the sp line method of fractional steps. For lower Reynolds numbers, about Re/Re-c less than or equal to 2 (Re-c is critical Reynolds number), numerical resul ts confirm the experimentally observed behavior reported by Goujon-Durand e t al. (Phys. Rev. E 1994; 50:308), i.e. the maximum amplitude of the veloci ty component oscillating with the fundamental frequency follows fairly well the scaling law A(max) similar to (Re - Re-c)(0.5) and the position X-max similar to (Re - Re-c)(-0.5). The influence of the trapezoidal shape on the value of the critical Reynolds number and on the vortex shedding is briefl y discussed. It appears that the influence of the trapezoidal height H is t he dominant influence on the value of Strouhal number when compared with th e effect of the smaller trapezoidal base width B. (C) 2001 Elsevier Science Ltd. All rights reserved.