Scale Effects Investigation on the Stability and Control Characteristics of an Advanced Twinjet Transport

The value of computational fluid dynamics, CFD, delivered to date has mainly been related to its application to high-speed cruise design. To increase its applicability CFD must apply to the full flight envelope frequently characterised by large regions of separated flows. These flows are encountered by transport aircraft at low speed with deployed high lift devices, at their structural design loads conditions, or subjected to in-flight upsets that expose them to speed and/or angle-of-attack conditions outside the envelope of normal flight conditions to name a few. Such flows can only be characterised by the Navier-Stokes equations. This paper will report the progress toward CFD for full flight envelope. The CFD methods in use at Boeing will be described. Examples presented will address high-lift, loads and stability and control concerns including Reynolds scaling from wind tunnel to flight, vortex generator simulation, spoiler and horizontal tail effectiveness. In general, results shown are in ‘good enough’ agreement with experimental data. Deficiencies and the need for further algorithm and process improvement are noted. The need for automation to enable the large scale use of CFD will also be discussed.

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“…Results from an initial study of applying Navier-Stokes CFD to look at Reynolds number effects on aileron controls were presented in Ref. 17.…”

Section: Lateral Control Characteristicsmentioning

confidence: 99%

“…Scale effects on high-speed stabiliser and elevator effectiveness were also investigated through NTF testing and computational analysis (17) . Results are shown near cruise Mach number and at two separate Reynolds numbers.…”

Section: Longitudinal Controlmentioning

confidence: 99%