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USE OF EXTENDED POD TO ANALYSE A MULTI-SENSOR MEASUREMENTS IN A SEPARATED TURBULENT FLOW

Cedric Hoarau
Laboratoire d'Etudes Aérodynamiques (LEA UMR 6609), Téléport 2 , 1 Av. Clément Ader, BP 40109, 86961 Futuroscope Chasseneuil , FRANCE

L. Duong
Laboratoire d'Etudes Aérodynamiques (LEA UMR 6609), Téléport 2 , 1 Av. Clément Ader, BP 40109, 86961 Futuroscope Chasseneuil , FRANCE

Jacques Boree
Institut Pprime, UPR CNRS 3346, ENSMA, Universite de Poitiers, BP 40109, 86961 Futuroscope Chasseneuil Cedex, France

Janick Laumonier
Laboratoire d'Etudes Aérodynamiques (LEA UMR 6609), Téléport 2 , 1 Av. Clément Ader, BP 40109, 86961 Futuroscope Chasseneuil , FRANCE

Yves Gervais
Département Fluides, Thermique et Combustion Institut Pprime CEAT, Poitiers, FRANCE

Abstract

Wall pressure array measurements and LDV single point measurements of the velocity obtained on a 30° forward facing ramp are discussed in this paper. Mean and fluctuating signals are analyzed both in the mean separated region and in the recovering boundary layer flow. The results evidence the signature of both flapping and vortex shedding mechanisms in agreement with classical references. POD and Extended POD are then used to educe the length and time scale contribution of the shear layer structures on the pressure trace downstream of separation. We prove that the correlated pressure signal downstream the mean separation length carries the properties of the distorted mixing layer eddies being advected and dissipating in the outer boundary layer flow. A simple physical model is proposed.