Flow Control of NACA Flush Inlet Based on Vane Vortex Generators

NACA flush inlets exhibit favorable low-drag performance, yet they suffer from low total pressure recovery and high flow distortion, which limit their widespread application. To address these issues, a passive flow control method using vane vortex generators (VVGs) is proposed for NACA-type inlets. First, CFD numerical simulations are conducted to analyze the inlet flow field characteristics and elaborate the design principle of VVGs. Next, orthogonal tests are performed to comprehensively investigate the effects of VVG parameters on the flow field of the NACA flush inlet. Finally, the aerodynamic coupling mechanism between VVGs and the NACA flush inlet is explored in depth through analysis of limiting streamlines, total pressure recovery distribution, Mach number distribution and swirl angle distribution. The results show that VVGs optimize the distribution of low-momentum airflow inside the inlet via flow guidance. The micro vortices generated by VVGs enhance mixing between low-energy and high-energy airflow within the boundary layer, thereby suppressing flow separation in the duct. Compared with the baseline configuration, the maximum reduction in the total pressure distortion index (DC60) for the controlled configuration is approximately 55%.