Marshalist

Wingtip vortices

Wingtip vortices are circular patterns of rotating air left behind a wing as it generates lift. The name is a misnomer because the cores of the vortices are slightly inboard of the wing tips. Wingtip vortices are sometimes named trailing or lift-induced vortices because they also occur at points other than at the wing tips. Indeed, vorticity is trailed at any point on the wing where the lift varies span-wise (a fact described and quantified by the lifting-line theory); it eventually rolls up into large vortices near the wingtip, at the edge of flap devices, or at other abrupt changes in wing planform. Wingtip vortices are associated with induced drag, the imparting of downwash, and are a fundamental consequence of three-dimensional lift generation. Careful selection of wing geometry (in particular, wingspan), as well as of cruise conditions, are design and operational methods to minimize induced drag. Wingtip vortices form the primary component of wake...

High-speed train collides with tractor trailer: 2 injured, traffic to London disrupted | VRT NWS: news

A high-speed train travelling between Lille(France) and Brussels collided with a stationary tractor trailer on a level crossing at Beclers (Tournai - Hainaut) earlier today railtrack operator Infrabel has confirmed. Two passengers on the train were injured. No trains were running to and from London for a while this morning. The accident happened at 7.55am CEST. As a result, traffic is disrupted on rail line 94 between Tournai and Halle (Flemish Brabant). Emergency services are at the scene.

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