1. Department of Mathematics, North Carolina State University, Raleigh, NC 27695, USA
2. Thales Alenia Space, Cannes, France
3. INRIA Paris, 2, rue Simone Iff, 75589 Paris Cedex 12, France
4. Universite de Toulouse-INPT-UPS, Institut de Mecanique des Fluides, 31000 Toulouse, France
5. STROMALab, Universite de Toulouse, Inserm U1031, EFS, INP-ENVT, UPS, CNRS ERL5311, Toulouse, France
6. Department of Mathematics, Imperial College London, London SW7 2AZ, UK