Interacting Wakes of Two Normal Flat Plates

Subtitle: An investigation based on phase averaging of LDA signals

Article type: Research Article

Authors: Auteri, F. | Belan, M. | Cassinelli, C. | Gibertini, G.

Affiliations: Politecnico di Milano, Dipartimento di Ingegneria Aerospaziale Via La Masa 34, 20156 Milano, Italy. E-mail: Franco.Auteri@polimi.it, Marco.Belan@polimi.it, Giuseppe.Gibertini@polimi.it

Abstract: The flow around two bluff bodies in tandem is an interesting phenomenon whose nature strongly depends on the distance between the bodies. In this work oil smoke visualizations of the flow around two normal flat plates in tandem configuration are compared with phase averaged Laser Doppler Anemometry measurements of the flow field for a full period. Phase averaging is exploited to resolve the mean time evolution of the flow and the signal from a single constant temperature hot wire probe is employed as phasing reference. The flow-field information obtained from visualizations agrees well with quantitative indications provided by measures, and the comparison allows to precisely understand what information can be extracted from simple visualizations. As a result, new insight in flow mechanism is obtained from the analysis of the flow data showing that, for the analyzed plate distance, the gap between the two plates behaves substantially as a cavity while the vortex formation process takes place in the wake region behind the aft plate.

Keywords: Flat Plate, Bluff bodies, Wake Interference, Laser Doppler Anemometry, Phase averaging

Journal: Journal of Visualization, vol. 12, no. 4, pp. 307-321, 2009