The Extension of P.O.D. to Complex System with Non-Homogenous Boundary Conditions, Application to a Turbulent Pulsed Jet

The Proper Orthogonal Decomposition (or P.O.D.) provides a new approach for the simulation of unsteady flows. In a preliminary phase, a classical approach is used to compute a set of typical solutions of the P.D.E., snapshots are stored and used to derive a basis. Galerkin projection on this basis leads to a low order O.D.E. which is used to simulate at extremely reduced cost, new similar flow configurations or longer time periods. In a previous work, the author demonstrated the feasibility of POD-based simulation for laminar compressible unsteady flows with space discretisation based on unstructured meshes. The work that is presented in the paper includes first an extension of our previous work to unsteady turbulent flows modeled by the Spalart-Allmaras turbulence model. Next, the extension of the method to the treatment of inhomogenous Dirichlet boundary conditions is described. This allows the P.O.D. based simulation of pulsed jets. The paper also demonstrates the capability of P.O.D. based approaches to simulate pulsed jets flows over a certain range of frequency and mass flow parameters. Finally, the O.D.E. system resulting from projection on the P.O.D. basis is considered as a (non linear) representative dynamic system for flow control. An examples of application to flow control complete the paper.