Abstract：The research focuses on the different delayed functions in the delayed detached eddy simulation (DDES) methods by employing the supersonic base flow as the validation case. Through systematic comparisons with the experimental data and detailed analyses, the distributions and shielding behaviors of different delayed functions together with resolving capabilities of different models are investigated. Results show that DDES-F2 provides protection in the largest area, leading to a large RANS region with a great deal of turbulent scales being modeled. Therefore, the resolving capabilities of the model are inhibited, resulting in fewer small-scale flow structures and lower turbulent fluctuations than the measurements. On the contrary, DDES-Fd obtains the smallest RANS region, and the predicted backflow velocity agrees well with the experimental data in the recirculation region, while the intensity of velocity fluctuations are overpredicted at some locations. DDES-F1 behaves appropriately in this supersonic separated flow and reproduces the experimental data very well, providing sufficient protection without impairing the model’s numerical accuracy.
