Michel Bergmann 
  Charge de Recherches
INRIA  centre Bordeaux Sud-Ouest
  Team MC2
  Phone : +33 (0)5 40 00 69 54
  Fax     : +33 (0)5 40 00 21 17
  Mailto: Michel.Bergmann at inria.fr 

 Institut de Mathematiques de Bordeaux

Mathematiques Appliquees de Bordeaux
  351 cours de la Liberation
33405 TALENCE cedex


Research interests  [more details]

Mathematical modelling - Reduced Order Models - Numerical Simulations - Optimization and control - Stability Analysis...

... Toward applications
(windtubine, UAVs, Boat Propellers, Fluid-Structures Interactions)

Mathematical modelling

Reduced Order Models

Numerical Simulations

  • Finite Element Method
    2D, Delaunay Triangulation
    [POF05] [POF06a] [POF06b]
  • Finite Volume, Multigrid Method
    2D,Cartesian Meshes
    with penalization
  • Finite Differences with projection methods
    3D, 2nd order, Cartesian Grids, Immersed Boundary, Level Set

    Development of the code NaSCar (see movies)

Optimization and Control

  • Dual adjoint methods / optimal control & robust control LQR
    Drag reduction
    [POF05] [NNFM07] [MI07] [JCP08]
  • DNS & POD + trust region (TRPOD)
    Drag Reduction
    [JCP08] [NNFM07]
  • Artificial neural networks, genetic algorithms, inverse methods
    Control and estimation of the ingnition point of forest fire

Sability Analysis

  • Reduced Order Models
  • Sedimentation of bodies

Some applications of NaSCar solver

Self-propelled swimmers
(Simualtions with Cartesian Meshes + Penalization + Level Set)

3D Fish like swimming of a real makerel fish
(Obtained from pictures with skeleton and optimal transport)

             3D jelly fish like swimming                                 3D Ray swimming   

another 3D Ray Swimming.    


Control of Self-propelled swimmers

Turbulent fish-like swimming.
Control of the tail amplitude to reach a desired swimming velocity.

Fish maneuvers.
Goal: large fish sould go towards the small fish
Control the swimming law of the large fish by adding adaptive curvature.

Fluid-structure Interactions: Elastic body

Wave power extraction with an elastic "water snake"
("strong" implicit coupling between fluid and elastic structure)

Inertial Sea Wave Energy Converters

The energy is converted thanks to a gyroscope inside the floater.


Wind turbine ("low precision").

Wind turbine ("high precision") with tip vortices.

Boat Propeller
(Thrust generation)

turbulent (Smagorinsky-Lilly LES model).

Boat (interface air/water/boat)

Air-water interface is computed with Continuous Surface Force model

Sedimentation of bodies

2D sedimentation of a  cylinder (presence of instability at Re=30...)

3D pressure distribution on a falling disk in a tube.

Sedimenation of spheres with contacts modeled with Newtonian central forces

Some instabilities

Rayleigh Taylor with density ratio 3

Rayleigh Plateau (with curvature limitator to allow 2D isntability).

Drag minimization of the cylinder wake in laminar regime   

Natural uncontrolled flow. Cd=1.40 [video 7.2Mo]

Flow generated with optimal parameters found by TRPOD method. Cd=0.99 [video 2.9Mo] 

Workshop on POD [more details]

Thanks to all speakers, some slides presentations can be downloaded in pdf format here.


Photos (restricted access)

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