Levich Institute Seminar Announcement, 10/21/2008
Tuesday, 10/21/2008
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Dr. Jorge Peixinho
City College of CUNY
Levich Institute

"Transition To and From Turbulence in Pipe Flow"


ABSTRACT


Transition to turbulence in a pipe has been described as an unsolved problem and outstanding challenge in hydrodynamic stability theory since all theoretical work suggests that the flow should be laminar and yet most pipe flows are turbulent. A discussion of experimental investigations into the stability of the flow along a pipe will be given. The transition to turbulence is catastrophic when a well-defined finite amplitude of perturbations is exceeded. The stability threshold scales inversely proportional to the Reynolds number, with a sharp cut off at low Re values. Depending on the type of the perturbations, the scaling shifts and changes indicating that several mechanisms can lead to turbulence. On the other hand, the decay from the turbulent state exhibits systematic exponential behavior with diverging timescales which are indicative of critical behaviour. The long transients contain spatio-temporal coherence which suggest connections with recent theoretical developments.

BRIEF ACADEMIC/EMPLOYMENT BACKGROUND:

  • Since 2008. USA Post-Doc in Levich Institute, CCNY (granted by RF CUNY and Chevron)
  • 2006-2008. Japanese Post-Doc. at the University of Tokyo, Department of Mechanical Engineering, FEL (granted by JSPS)
  • 2004-2006. UK Post-Doc. at the University of Manchester, Department of Physics and Astronomy, MCND (granted by EPSRC)
  • 2001-2004. French Ph.D. from the University Henri Poincare at the LEMTA (granted by ANRT and Schlumberger)