Flight Maneuverability Characteristics of the F-16 CFD and Correlation with its Intake Total Pressure Recovery and Distortion

Abstract

:An investigation of the intake pressure recovery and distortion effects observed by varying maneuverability conditions of the F-16 was conducted. Simulations were conducted by using the Partial Differential Equation (PDE) calculator COMSOL. Results were validated with the classical s-duct, showing reasonable qualitative agreement. The maneuverability of the F-16 was defined using three factors: Mach number, angle of attack and angle of sideslip. The values of pressure recovery and distortion were measured at the Aerodynamic Interface Plane (AIP). Two sets of simulations were conducted: one to compare the sea level and 10 km altitude flight condition and another to correlate the required air intake and engine performance with pressure recovery and distortion at the AIP. Results of the flight level comparisons showed a slightly higher pressure recovery at 10 km of 0.985 compared to sea level condition value of 0.983. Distortion coefficient values for both conditions were however similar at 0.120. The difference in recovery values is attributed to the less viscous characteristic of air at higher altitude. This resulted in lower secondary flow formations in the intake. With increasing altitude, temperature plots showed a linear decreasing profile throughout the intake. The study provides a platform to a future model which couples the results obtained from the intake as inlet conditions to turbine flow simulations. This would provide a more holistic understanding of the propulsion system in the F-16.