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Climatechange is increasing global-mean tropospheric temperatures, but the localised trends are uneven, including cooling the lower stratosphere and lifting the tropopause. The wind speeds are also being modified, both at the surface and aloft. A further effect, additional to wind and temperature alone, is of increasing fluctuations and severity of extreme weather. These are impacting air transport, and this will continue. The effects are known to include increased take-off distances where excess runway lengths exist and reduced payloads where they do not, increased en-route flight times, increased frequency and severity of encounters with clear air turbulence in some regions, changed patterns of wildlife — particularly bird — activity in some regions (potentially also for other anthropogenic reasons) are shifting locations of flight safety hazards, and increased burdens upon airport and associated infrastructure. There is increasing understanding and acknowledgment by companies and authorities of these effects and the importance of mitigating them, although this is not universal and there are as yet no universally understood best practices for air transport climate change mitigation. [ABSTRACT FROM AUTHOR]

This article explores, theoretically and experimentally, Coanda effect and upper surface blowing over an annular wing. Also, presented are a simple mathematical/empirical model and an experimental strategy to evaluate lift generated by a blown-annular wing. It has been shown that the wing is capable of deflecting the flow by ∼90° with an efficiency of ∼61 per cent with reference to the undeflected horizontal thrust from the source. The analytical review and experimental data presented will enable an aircraft designer to deduce this particular powered-lift system for V/STOL applications at the preliminary design stage. [ABSTRACT FROM AUTHOR]