Sharp Transition in the Lift Force of a Fluid Flowing Past Nonsymmetrical Obstacles: Evidence for a Lift Crisis in the Drag Crisis Regime
TypeArticles dans des revues avec comité de lecture
Bluff bodies moving in a fluid experience a drag force which usually increases with velocity. However in a particular velocity range a drag crisis is observed, i.e., a sharp and strong decrease of the drag force. This counterintuitive result is well characterized for a sphere or a cylinder. Here we show that, for an object breaking the up-down symmetry, a lift crisis is observed simultaneously to the drag crisis. The term lift crisis refers to the fact that at constant incidence the time-averaged transverse force, which remains small or even negative at low velocity, transitions abruptly to large positive values above a critical flow velocity. This transition is characterized from direct force measurements as well as from change in the velocity field around the obstacle.
Files in this item
Showing items related by title, author, creator and subject.
DEPARDAY, Julien; BOT, Patrick; HAUVILLE, Frédéric; AUGIER, Benoit; RABAUD, Marc (Elsevier, 2016)Yacht downwind sails are complex to study due to their non-developable shape with high camber and massively detached flow around thin and flexible membranes. Numerical simulations can now simulate this strong fluid-structure ...
DEPARDAY, Julien; BOT, Patrick; HAUVILLE, Frédéric; AUGIER, Benoit; RABAUD, Marc; MOTTA, Dario; LE PELLEY, David (SNAME, 2017)While sailing offwind, the trimmer typically adjusts the downwind sail “on the verge of luffing”, occasionally letting the luff of the sail flap. Due to the unsteadiness of the spinnaker itself, maintaining the luff on the ...
DEPARDAY, Julien; BOT, Patrick; HAUVILLE, Frédéric; AUGIER, Benoit; RABAUD, Marc; MOTTA, Dario; LE PELLEY, David (2016)While sailing offwind, the trimmer typically adjusts the downwind sail "on the verge of luffing", letting occasionally the luff of the sail flapping. Due to the unsteadiness of the spinnaker itself, maintaining the luff ...
Isometric point of lateral femoral condyle analysis with in vitro kinematic study in order to position the extra-articular part of an ACL reconstruction ANKRI, Marine; KHIAMI, Frédéric; ROCHCONGAR, Goulven; JOUBERT, Thomas; PILLET, Hélène; THOREUX, Patricia; ROUCH, Philippe (Columbia University, 2015)The anterior cruciate ligament (ACL) injury leads to an anterior laxity associated with a variable rotational laxity. Without any treatment, this lesion can have functional consequences (instability, disturbance of sport ...