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Journal of Flow Visualization and Image Processing
SJR: 0.161 SNIP: 0.312 CiteScore™: 0.1

ISSN Print: 1065-3090
ISSN Online: 1940-4336

Journal of Flow Visualization and Image Processing

DOI: 10.1615/JFlowVisImageProc.v2.i1.20
pages 15-27

FLOW VISUALIZATION INVESTIGATION AROUND HELICOPTER ROTOR BLADE TIPS IN HOVERING FLIGHT

E. Berton
Institut de Mécanique des Fluides, Université d'Aix-Marseille II, UM-34 du C.N.R.S., 13009 Marseille, France
D. Favier
Institut de Mécanique des Fluides, Université d'Aix-Marseille II, UM-34 du C.N.R.S., 13009 Marseille, France
C. Maresca
Institut de Mécanique des Fluides, Université d'Aix-Marseille II, UM-34 du C.N.R.S., 13009 Marseille, France
M. Nsi Mba
Institut de Mécanique des Fluides, Université d'Aix-Marseille II, UM-34 du C.N.R.S., 13009 Marseille, France

ABSTRACT

Rotor tip vortex formation and roll-up have been investigated using a flow visualization method coupled with a digital image processing technique. Emphasis is placed on the effect of the blade tip shape on the vortex structure and stability along its path. Particular attention is given to the influence of the tip geometry modification on the flowfield generated around the blade and its wake. For each blade configuration, the experiments include visualizations of the vortical structures generated by the blade tip and measurements of the tip vortex path. When compared to the rectangular tips, the evolutive tips are shown significantly to modify the wake geometry and to generate a dual vortex structure that produces a stronger instability of the tip vortex path. This vortex instability significantly affects the airloads distribution along the blade span.