Thematic Program on Incompressible Fluid Dynamics -- Seminars


Click on the desired week to see the seminar for that period.


Week 1: Mar 10-14 Week 2: Mar 17-21 Week 3: Mar 24-28
Week 4: Mar 31- Apr 04 Week 5: Apr 07-11 Week 6: Apr 14-18
Week 7: Apr 21-25 Week 8: Apr 28-May 02 Week 9: May 05-09
Week 10: May 12-16 Week 11: May 19-23 Week 12: May 26-30
Week 13: Jun 02-06 Week 14: June 09-13 %%%%%%%%%%




 




Week 1: March 10 to 14 School "Around Vortices"
Week 2: March 17 to 21 School "Around Vortices"
Week 3: March 24 to 28  Seminar        

When:


      Date > Tue (Mar 25)
      Time > 14:00 to 15:00

Where:
Auditorium 3

Speaker: Miles Wheeler (Brown University)

Title:
  Large-amplitude solitary waves with vorticity

Abstract:
The water wave equations describe the motion of an incompressible inviscid fluid under the influence of gravity which is bounded above by a free surface under constant (atmospheric) pressure. In this talk, we will construct exact solitary water waves of large amplitude and with an arbitrary distribution of vorticity. Starting from a shear flow with a flat free surface, we use a degree-theoretic continuation argument to construct a global connected set of symmetric solitary waves of elevation, whose profiles decrease monotonically on either side of a central crest. We will discuss solitary waves generated by a non-constant pressure on the free surface.
Week 4: March 31 to April 04 Seminar    
   
THIS SEMINAR WAS CANCELLED

When:


      Date > Tue (Apr 01)
      Time > 14:00 to 15:00

Where:
Auditorium 3

Speaker: Helena J. Nussenzveig Lopes (UFRJ)

Title:
  Convergence of Euler-alpha to Euler with Dirichlet conditions and indifference to the boundary layer

Abstract:
In this talk we will discuss a recent result by the author with M. Lopes Filho, E. Titi and A. Zang concerning the asymptotic behavior of solutions of the Euler-alpha system, when the parameter alpha tends to zero. We study this limit in a 2D bounded domain with no-slip boundary condition and we prove that, under suitable hypothesis, the limit satisfies the incompressible Euler system. 
Week 5: April 07 to April 11 Seminar        

When:


      Date > Tue (Apr 08)
      Time > 14:00 to 15:00

Where:
Auditorium 3

Speaker: Jean-Pierre Puel (École Polytechnique, France)

Title:
  Controllability of fluid flows

Abstract:This presentation will give an overview on the controllability for fluid flows. There will be no technical proof. First of all we will describe in an abstract situation the various concepts of controllability for evolution equations. We will then present some problems and results concerning the controllability of systems modeling fluid flows. First of all we will consider the Euler equation describing the motion of an incompressible inviscid fluid. Then we will give some results concerning the Navier-Stokes equations, modeling an incompressible viscous fluid, and some related systems, in particular the case of what is called Lagrangian control and which might lead to a lot of developments. Finally, we will present a first result of controllability for the case of a compressible fluid (in dimension 1) and some important open problems.
Week 6: April 14 to April 18 Seminar        

When:


      Date > Tue (Apr 15)
      Time > 14:00 to 15:00

Where:
Auditorium 3

Speaker: Dimitry S. Agafontsev (P.P. Shirshov Institute of Oceanology of the Russian Academy of Sciences)

Title:
  On the singularities development in the framework of 3D Euler equations

Abstract: We study numerically development of singularities of vorticity field for 3D Euler equations on grids of up to 2048^3 nodes. We examine nearly arbitrary smooth symmetric and non-symmetric initial data. For several realizations of the initial data - both symmetric and non-symmetric - and as long as our simulations are reliable we observe development of singularities when absolute maximum value of vorticity increases with time exponentially. Geometric characteristics of singularity regions also develop exponentially and close to self-similar way. In addition we observe evolution of local maximums for vorticity field and those with sufficiently high vorticity also develop exponentially. Our results strongly suggest that in the framework of 3D ideal incompressible hydrodynamics smooth initial data may generate singularities of vorticity field and that these singularities develop exponentially. 
Week 7: April 21 to April 25 NO SEMINAR DUE TO HOLIDAY
Week 8: April 28 to May 02
EXCEPTIONALLY, DUE TO THURSDAY-FRIDAY HOLIDAY
THIS SEMINAR WILL BE HELD WEDNESDAY, 15-16:00, ROOM 333

Seminar

When:

      Date > Wed (Apr 30)
      Time > 15:00 to 16:00

Where:
Room 333

Speaker: Jinkai Li (Weizmann Institute)

Title:
  On the singularities development in the framework of 3D Euler equations

Abstract: In this talk I will discuss the local well-posedness of strong solutions to the Ericksen-Leslie system modeling the evolution of nematic liquid crystals. Local well-posedness of strong solutions to this system is obtained by using the Ginzburg-Landau approximation. Several blow-up criteria are established to characterize the maximal existence time of strong solutions to the Ericksen-Leslie system. It is shown that the Ginzburg-Landau system strongly converges to the Ericksen-Leslie system up to the maximal existence time of the strong solutions of the Ericksen-Leslie system.
Week 9: May 05 to May 09 
Seminar        

When:


      Date > Tue (May 06)
      Time > 14:00 to 15:00

Where:
Auditorium 3

Speaker: Yanqiu Guo (Weizmann Institute)

Title:
  Persistency of analyticity for nonlinear wave equations and the cubic Szego equation

Abstract: Gevrey classes were introduced by Maurice Gevrey in 1918 to generalize real analytic functions. Functions of Gevrey classes can be characterized by an exponential decay of their Fourier coefficients. This characterization has been proved useful for studying analytic solutions of various nonlinear PDEs, since the work by Foias and Temam (1989) on the Navier-Stokes equations. We use this technique to investigate the persistency of spatial analyticity for nonlinear wave equations (joint work with Edriss S. Titi), and the cubic Szego equation (joint work with Patrick Gerard and Edriss S. Titi). An advantage of this method is that it provides a lower bound for the radius of the spatial analyticity of the solutions.
Week 10: May 12 to May 16   EXCEPTIONALLY, THIS WEEK THERE WILL BE NO SEMINAR. INSTEAD, LECTURE 1 OF THE MINICOURSE WILL BE HELD ON Tueday, MAY 13, Auditorium 3.
Week 11: May 19 to May 23 Seminar   

THIS WEEK THERE WILL BE TWO SEMINARS, HELD AT THE FEDERAL UNIVERSITY OF RIO DE JANEIRO    

When:


      Date > Tue (May 20)

Where:
Room C-119 -- Institute of Mathematics, Universidade Federal do Rio de Janeiro

     
Time > 10:00 to 11:00


Speaker:
Maria Schonbek (University of California, Santa Cruz)

Title:
   L^2 ASYMPTOTIC STABILITY  OF MILD SOLUTIONS  TO THE NAVIER-STOKES SYSTEM

Abstract: We consider the initial value problem for the Navier-Stokes equations modeling an incompressible fluid in three dimensions:

u_t + u \cdot \nabla u + \nabla p = \Delta u + F,

                                                (x,t) \in R^3 \times (0,\infty)

div u = 0

u(x,0) = u_0(x).
 

It is well-known that this problem has a unique global-in-time mild solution for a sufficiently small initial condition    and for a small external force  in suitable scaling invariant spaces. We show that these global-in-time mild solutions are asymptotically stable under every (arbitrary large) L^2-perturbation of their initial conditions.



      Time > 13:00 to 14:00


Speaker: Claude Bardos
(University of Paris 7—Denis Diderot (emeritus); Laboratory Jacques Louis Lions University of Paris 6—Pierre and Marie Curie; the Wolfgang Pauli Institute in Vienna.)

Title:  DIFFUSION APPROXIMATION FOR STRONGLY HETEROGENEOUS DIFFUSION MEDIA

Abstract: In this talk, which in particular is a review of a joint project with Etienne Bernard , François Golse and Rémi Sentis, I will revisit classical and more recent methods concerning the diffusion approximation of the linearized Boltzmann equation in strongly Heterogenous Media. It gives an opportunity to introduce the moment method.

Eventually  remarks to the derivation from the billard dynamic will be given.

Week 12: May 26 to May 30 4th. Workshop on Fluids and PDE
Week 13: June 02 to June 06 Seminar        

When:


      Date > Tue (June 03)
      Time > ***15:30 to 16:30 SPECIAL TIME

Where:
Room 228 SPECIAL ROOM

Speaker: Edriss S. Titi (Weizmann Institute of Science and University of California - Irvine)

Title:
  Dynamical Systems Approach to Turbulence

Abstract: In this talk we will survey the dynamical systems approach for investigating turbulent flows. Moreover, we will implement  this dynamical systems framework to design finite parameters feedback control and data assimilation algorithms.
Week 14: June 09 to June 13    
NO FORMAL ACTIVITIES DURING THIS LAST WEEK