Aerodynamic Simulation of a Tactical Aerostat and evaluating the longitudinal static coefficients

In this paper, the computational fluid dynamics simulation of a tactical aerostat is conducted and the longitudinal static coefficients of the aerostat is evaluated. The simulation is conducted using the Fluent software and the Spalart-Allmaras turbulent model is used. First, in order to validate the numerical method and the applied turbulent model, a famous airship hull is simulated and the drag coefficient at zero angle of attack is compared with the references and the CD0 is in very good agreement with references. Then, the designed aerostat is simulated and the pressure and Y+ contours and the streamlines around the aerostat are presented in angle of attack -10≤AoA≤30. Furthermore, the aerodynamic longitudinal coefficients are calculated for 5 and 20 m/s. The results show that the aerodynamic coefficients do not vary significantly with the change of velocity and the pitch moment coefficient about the nose of the designed aerostat has a negative slope. Comparing the pitch moment coefficient of the designed aerostat with two American a Korean aerostats depict that the designed aerostat has more static stability.