Study of the compressible flow in a diffusing S-duct

Wellborn, Steven R.; Reichert, Bruce A.; Okiishi, T. H.

doi:10.2514/3.23778

Cited by 92 publications

(129 citation statements)

References 7 publications

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“…Pressure probes placed at the end of the second bend indicated the formation of a low total pressure region resulting from the adverse static pressure gradients, as well as the higher centrifugal forces acting on the boundary layers of the fluid present at the bends. The circular s-duct geometry was an excellent platform for validation of a turbulence code (Wellborn et al, 1993;Harloff et al, 1992). An F-16 like geometry study describes the effect of centerline curvature and changing crosssectional shape on intake performance (Towne and Anderson, 1981).…”

Section: Introductionmentioning

confidence: 99%

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

Ibrahim

Wong³

2011

Engineering Applications of Computational Fluid Mechanics

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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.

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Section: Introductionmentioning

confidence: 99%

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

Ibrahim

Wong³

2011

Engineering Applications of Computational Fluid Mechanics

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“…4). Although this is mainly a qualitative method to evaluate separation, it is similar to previous work in this area [3,11]. For the datum configuration, the nominal centerline separation arises at an axial distance of 187 mm from the inlet.…”

Section: Flow Control Characteristicsmentioning

confidence: 68%

“…The time averaged in-plane velocity streamlines for the datum configuration ( Fig. 12a) indicates the well-known symmetrical pair of counter rotating vortices observed by Wellborn et al [3]. Relative to the datum configuration, all the VG configurations have a notable impact on the out of plane velocity flow field at the AIP (Fig.…”

Section: S-piv Resultsmentioning

confidence: 95%

“…This is associated with a loss in total pressure in the lower sector of the AIP [3,11,12]. However, it was demonstrated by Berens et al [13] that time averaged data can be misleading, and the use of Delayed Detached…”

Section: Fig 1 S-duct Geometry Definitionmentioning

confidence: 99%

“…However, S-shaped intake diffusers for the propulsion system are susceptible to high levels of flow unsteadiness and distortion. This is typically driven by secondary flows and local flow separations [2,3]. As a result, complex total pressure and swirl distortion fields, with significant vortical regions and large unsteady perturbations, are presented to the first stage of the compression system.…”

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confidence: 99%

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