Seatific , cilt.1, sa.1, ss.15-25, 2021 (Hakemli Dergi)
In the present paper, two-dimensional unsteady flows over circular cross-section cylinders
are analyzed numerically. The effects of placement of the cylinders are investigated for two
different arrangements: tandem and side-by-side. Several turbulence models are tested, and
it is found that Spalart-Allmaras turbulence model is the best among one- and two-equation
turbulence models. The most appropriate time step, which is one of the important parameters
in unsteady simulations, is found as 0.002 seconds. After successful validations, the cylinders
are positioned as side-by-side and tandem. The effects of the arrangement on flow regime, drag
coefficient, lift coefficient and Strouhal number are presented for various distances between
the cylinders. It is found that the flow is almost steady without any vortex in the gap when
cylinders are in tandem and the gap between them is low. In contrast, the interactions are
strong in case of side-by-side arrangement at the lowest gap. When the gap increases, the flow
is affected that results in change on the global parameters.