International Journal of Science, Engineering and TechnologyAuthors: Le Thanh Nguyen, Duc Dung Nguyen, Van Huong Ngo
Abstract: This paper evaluates the aerodynamic effects of an external-store configuration consisting of two auxiliary fuel tanks and two OFAB-100-120 bombs on the aerodynamic characteristics of a combat aircraft using the computational fluid dynamics (CFD) method. A three-dimensional model of the aircraft with the investigated external stores was developed in SolidWorks and analyzed using ANSYS CFX. The computational study was performed at an altitude of H = 4 km for two Mach numbers, M = 0.4 and M = 0.8, over an angle-of-attack range from 0° to 21° with zero sideslip. The external stores modify the local flow field near the pylons and alter the pressure distribution over the wing. At M = 0.8, the flow field becomes more sensitive to the geometry of the external-store region because local supersonic regions and shock waves develop on the wing. The variation of the lift coefficient Cy with angle of attack is also affected. For the investigated external-store configuration, at M = 0.4, Cy increases approximately linearly from 0° to 15°, increases more gradually from 15° to 18°, and then decreases for α > 18°. At M = 0.8, Cy increases approximately linearly from 0° to 9°, increases gradually from 9° to 16°, and begins to decrease for α > 16°. Compared with the clean configuration, the angle-of-attack range favorable for maintaining lift is therefore reduced at M = 0.8. Although the external stores alter the pressure distribution, their overall effect on lift is relatively small within the investigated configuration. Their more pronounced aerodynamic effect is an increase in frontal drag caused by the area and geometry of the external-store elements exposed to the airflow. The results indicate that each external-store configuration should be evaluated separately when assessing aircraft aerodynamic characteristics and operational performance.
