Effect of boattail angle on near-wake flow and drag of axisymmetric models: a numerical approach

Flow behavior around axisymmetric boattail surface was studied by numerical methods. A wide range of boattail angles from 0° to 24° was investigated to find the drag trend of the model. Numerical simulation was validated by experimental results with the same flow conditions. Results showed that the use of boattail model always has a positive effect on drag reduction. Total drag showed minimum value at boattail model of around 14°. Length of the recirculation after body decreases with increasing boattail angle up to 14° and then becomes constant at higher angle. The trend of boattail pressure drag showed similar to previous studies for high-speed flow. However, base drag showed different trend to previous observation. The base drag showed to be the most important parameter to determine drag trend of the model. The effect of flow fields around boattail on pressure distribution and drag is discussed in detail. © 2021, The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature.