Numerical Dissipation Effects on Massive Separation Around Tandem Cylinders

Three spatial schemes, the original Roe scheme and two high-order symmetric total variation diminishing schemes, whose dissipations are multiplied by a constant parameter or a function (called 0), are coupled with delayed detached eddy simulation to investigate the numerical dissipation effects on the massive separation flow around tandem cylinders. From the comparisons between the computations and the available measurements, the numerical dissipation has a significant influence on the mean and instantaneous flowfields. The original Roe scheme is too dissipative to predict the small scale turbulent structures, and it strongly suppresses the growth of resolved turbulence. The S6WENO5 schemes with constant-phi and adaptive-phi times of dissipation have similar performances and they well match the measurements. However, the S6WENO5 with constant-phi times (0.12 here) of dissipation is too empirical, and the small constant-phi times of dissipation cannot generally suppress the numerical oscillations near the wall and in the far fields. The S6WENO5 with adaptive dissipation provides the best performance.