Effects of Curvature and Area Distribution on S-Shaped Subsonic Diffuser Performance

In this work, effects of curvature and area distribution on S-shaped subsonic diffuser performance are computationally investigated with commercially available flow solver Fluent. Free-stream Mach number was taken as 0.75 for all computational runs while sideslip and angle of attack values vary between 0 and 5 Intake performance criterions; DC (Distortion Coefficient) and PR (Pressure Recovery) are depicted from computational domain and dependence of these parameters to the varying centerline curvature and area ratio for each flight condition is discussed. Results of the current study indicate that low distortion and high PR values are obtainable with the high curvature at the diffuser entrance and smooth area increase through the duct. Furthermore, it was shown that conventional design approaches as investigated in the current study are strong enough for designing subsonic/transonic S-shaped intake if negative effects that may originate from intake/airframe integrations such as boundary layer ingestion can be neglected.