Pire Action

The principle of worst action applied to valves

In supersonic flows, there is a favorable feature to create a lot of disorder.


In the supersonic portion of the expansion, flows are not one-dimensional. They are fragmented into multiple parts, each with a direction, speed, etc. These values differ significantly of a particle with its neighbor.
Furthermore, a given relaxation can be accomplished with nozzles of different forms. For example, we can build conventional nozzles, such as supersonic wind tunnels, or bell-shaped nozzles similar to those used in rockets.

Approaching them in a sandwich structure and everything changes.

CETIM-Informations : Quieter valves

About the Author Michel Pluviose

Michel Pluviose is Honorary Professor of Le Conservatoire National des Arts et Métiers (CNAM), and formerly Chair of Turbomachines who received his Doctor of Sciences from Université Pierre et Marie Curie - Paris VI. A hands-on engineer, Michel has worked with leading institutions, including as an engineer at Hispano-Suiza, SNECMA, Head of the laboratory at ATTAG (Association technique pour les turbomachines et turbines à gaz), Manager for compressible fluid activities at CETIM (Centre technique des industries mécaniques), and manager of the treaty « Machines hydrauliques et thermiques » at the « Techniques de l’Ingénieur » publications.

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