Numerical investigation of aerodynamics of missiles with wrap-around tail fins

Demirtaş, Uğurtan
This thesis investigates the aerodynamic characteristics of roll induction for missiles with wrap-around tail fins by performing steady-state RANS and unsteady URANS and DDES simulations. In RANS simulations, the effects of freestream Mach number and angle of attack on the roll moment coefficient are examined and compared with the wind tunnel results of Dahlke missile geometry. In order to analyze the effect of Riemann solver in unsteady cases, an exact Riemann solver is integrated into the open-source CFD flow solver SU2. In DDES simulations, the missile with wrap-around fins (WAF) is analyzed for Mach number of 0.5 and an angle of attack of 10° by using both exact Riemann solver (ER) and Roe’s approximate Riemann solver (ROE). The results show that the ER solver exhibits smaller dominant frequencies with larger amplitude than of ROE solver for complex separated flow solutions of wrap-around fins. A missile geometry with basic planar fins is also used as a validation case for the prediction of static and dynamic aerodynamic coefficients by performing RANS and URANS simulations. Due to the absence of unsteady experimental validation data for the missile geometries, NACA 0021 and OAT 15A airfoils are analyzed by both ER and ROE Riemann solvers. DDES simulation is performed for NACA 0021 airfoil in deep stall case at an angle of attack of 60°. ER solver shows smaller discrepancy in the frequency spectrum of the lift coefficient compared to the ROE solver with the experimental data. The URANS simulation is performed for OAT 15A airfoil in transonic shock buffeting case at Mach number of 0.73 and an angle of attack of 3.9°. There is no notable discrepancy with experimental data in the power spectral density of the pressure sensor located in the oscillatory shockwave path on the upper surface of the airfoil for both Riemann solvers.
Citation Formats
U. Demirtaş, “Numerical investigation of aerodynamics of missiles with wrap-around tail fins,” Ph.D. - Doctoral Program, Middle East Technical University, 2024.