Power Law Fluid Flow Passing Two Square Cylinders in Tandem Arrangement

Abstract

Twodimensional laminar flow of a powerlaw fluid passing two square cylinders in a tandem arrangement is numerically investigated in the ranges of 1< Re< 200 and 1 ≤ G ≤ 9. The fluid viscosity powerlaw index lies in the range 0.5 ≤ n ≤ 1.8, which covers shearthinning, Newtonian and shearthickening fluids. A finite volume code based on the SIMPLEC algorithm with nonstaggered grid is used. In order to discretize the convective and diffusive terms, the third order QUICK and the secondorder central difference scheme are used, respectively. The influence of the powerlaw index, Reynolds number and gap ratio on the drag coefficient, Strouhal number and streamlines are investigated, and the results are compared with other studies in the literature to validate the methodology. The effect of the time integration scheme on accuracy and computational time is also analyzed. In the ranges of Reynolds number and powerlaw index studied here, vortex shedding is known to occur for square cylinders in tandem. This study represents the first systematic investigation of this phenomenon for nonNewtonian fluids in the open literature. In comparison to Newtonian fluids, it is found that the onset of leading edge separation occurs at lower Reynolds number for shearthinning fluids and is delayed to larger values for shearthickening fluids.