Studies of local separations by the incident shock wave using a synthetic particle group method

The interactions between the incident shock wave (ISW) and turbulent boundary layer commonly occur in internal flows and are accompanied by intricate flow phenomena that merit comprehensive investigation. Given the balance between the computational efficiency and accuracy, the hybrid Reynolds-averaged Navier–Stokes and large eddy simulation methods, such as the improved delayed detached eddy simulation (IDDES), have emerged as the optimal choice for simulating flows involving incident shock wave and boundary layer interactions (SWBLIs) when coupled with an embedded turbulence model, such as the synthetic particle group method (SPOM), especially in three-dimensional (3D) scenarios. In this work, an IDDES-SPOM is first applied to simulate the quasi-3D SWBLI at a Mach number of 2.3. The comparative analysis confirmed that the IDDES-SPOM can mitigate the gray area problem of the original IDDES and enhance the prediction accuracy of local separation. The IDDES-SPOM is subsequently extended to simulate the hypersonic intake flow with 3D SWBLI at a Mach number of 6.0. The small-scale turbulent structures are triggered by the SPOM in the attached boundary layers past the side and bottom walls. This SWBLI includes very complex 3D flow patterns, especially near the corner region. Furthermore, the correlation between the intake width and dominant frequency is analyzed. A nondimensional frequency, which is based on the mean length of the recirculation zone, is introduced to normalize the impact of the intake width on the frequency features of the recirculation. The results indicate that a narrower intake can minimize local separation, thereby suppressing low-frequency characteristics.