Effect of the angle of attack on the YF-16 inlet

A k-ε numerical analysis of a fuselage-shielded inlet similar to that of the YF-16 was conducted. The simulations were conducted at Mach 0.6 at -10° to 40° angles of attack. Results were validated with experimental values obtained in the 90° bending pipe and circular S-duct. Pre-entry separation effects were simulated by a flat plate and offset by the diverter height. Results showed that the pressure recoveries resembled that of the YF-16 inlet, where negligible losses were up to 30° angle of attack (AOA). The increase in the angle of attack also resulted in the diminishing strength of the twin swirls

Swirl flow analysis of the port side F-5E intake using CFD

Swirl represents a form of energy loss, as the energy is used in accelerating the flow in the angular direction and does not contribute to engine thrust. Significant swirl flow in resulting in the fighter aircraft intakes during manoeuvres can result in an undesirable engine performance. The CFD study conducted using FLUENT shows that the F-5E intake is more sensitive to the negative angles of attack, especially for AOA at −10°, where bulk swirls were seen forming. In the results of Taguchi and ANOVA, both statistical model point to the angle of attack play the most significant role in determining a more undesirable swirl coefficient