eclille.gif (961 octets) Equipe de Mécanique des Fluides lmlura.gif (3800 octets)

Dupont Patrick   Laboratoire de Mécanique de Lille    Bd Paul Langevin, Cité Scientifique, F59655 Villeneuve d’Ascq cédex,

France , telephone.gif (200 octets)33 (0)3 20 33 53 80 , fax.gif (211 octets)33 (0)3 20 33 71 69, email.gif (172 octets) patrick.dupont@ec-lille.fr

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Interaction

of a vortex ring with a moving wall

 ani_vort_t2.gif (302938 octets)

Experimental Facility
Banc.gif (94659 octets) The experiment is done in a glass tank, 2.5 m long, 0.6 m large and 0.6 m deep, which is filled with water . The vortex ring generator works by gravity.  The moving wall is made of a transparent plastic strip of 0.25 m width, wrapped around two parallel rollers which are 2.1 m away. It slips on a plexiglass plate (2 m by 0,44 m). The strip speed can be varied from 0 to 2 m/s. Studies are performed by visualization and Particle Image Velocimetry (classic and holographic)

    

 

Tomoscopy
t2tomoR1.gif (4763 octets) t2tomoR5.gif (5087 octets) t2tomoR10.gif (5777 octets) t2tomoR13.gif (5759 octets)
Type 2 interaction as defined by Falco : the incident vortex ring disturbs the Stokes layer and gives rise to a hairpin vortex clearly visible. This case is particularly interesting because it corresponds to a phenomenon commonly observed  the turbulent boundary layers: the formation of hairpin vortices.

 

Vorticity maps
t2vort6.gif (2897 octets) t2vort7.gif (3005 octets) t2vort8.gif (3140 octets) t2vort10.gif (3251 octets) t2vort12.gif (2990 octets) t2vort16.gif (3005 octets)

    

fleche retour.gif (1291 octets) Return to home page Page impactv3  updated on Dec. 27th  98