Effect of groove depth on drag and aerodynamic characteristics of axisymmetric boattail models with longitudinal grooves

Reducing drag on boattail configurations remains a critical challenge in external aerodynamics. In this work, numerical simulations were conducted to examine the influence of longitudinal groove depth – represented by the groove-peak distance parameter A – on the flow behavior and drag characteristics of axisymmetric boattail bodies. The parameter A was varied between 0 and 0.3 times the body diameter (D). The computations employed the Reynolds-Averaged Navier–Stokes (RANS) equation for the similation. The k-ω SST turbulence model at a freestream velocity of 22 m/s. Results indicate that groove depth has negligible effect on drag at a 14° boattail angle, but at 18° a substantial reduction in drag of up to 11% was obtained for A = 0.3D. Analysis of pressure distribution, skin friction, and wake structure confirms that deeper grooves help suppress flow separation on the boattail surface. These findings highlight the importance of groove depth selection for optimizing aerodynamic efficiency in axisymmetric vehicles