Aerodynamic characteristics of axisymmetric boattail models with different number of longitudinal groove cavities

Reducing aerodynamic drag and increasing flying object performance is an important task in aerospace engineering. The high drag occurs for blunt base models, which are not only for missiles, and projectiles but also for building, bridges. This study presents numerical results regarding subsonic flow characteristics over axisymmetric boattail models equipped with longitudinal grooves, with the number of grooves ranging from 2 to 12. The standard model has a fixed boattail length of 0.7D and an angle 22°. The investigation employs numerical simulation methods utilizing the Reynolds-averaged Navier-Stokes (RANS) equations with the k-ω SST turbulent model. The boundary layer was captured well by the current simulation. The numerical results are initially validated against both simulated and experimental data from previous studies, ensuring accuracy and reliability. The findings indicate that an increase in the number of grooves from 0 to 4 results in a slight increment in drag. However, as the number of grooves is further increased from 6 to 12, a significant reduction in the model's drag is observed. Additionally, the flow patterns around the boattail model are visually depicted and analyzed to explain the drag trend of the model with different groove configurations