Three-dimensional Turbulent Boundary Layer in a Shrouded Rotating System |
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Authors: | Sébastien Poncet Anthony Randriamampianina |
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Institution: | 1.Laboratoire MSNM-GP, UMR 6181 CNRS,Technop?le Chateau-Gombert,Marseille,France;2.Institut de Recherche sur les Phénomènes Hors Equilibre,UMR 6594 CNRS - Universités d’Aix-Marseille I & II Technop?le Chateau-Gombert,Marseille cédex 13,France |
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Abstract: | A thre-dimensional direct numerical simulation is combined with a laboratory study to describe the turbulent flow in an enclosed
annular rotor-stator cavity characterized by a large aspect ratio G = (b − a)/h = 18.32 and a small radius ratio a/b = 0.152, where a and b are the inner and outer radii of the rotating disk and h is the interdisk spacing. The rotation rate Ω considered is equivalent to the rotational Reynolds number Re = Ωb
2/ν= 9 .5 × 104 (ν the kinematic viscosity of water). This corresponds to a value at which experiment has revealed that the stator boundary
layer is turbulent, whereas the rotor boundary layer is still laminar. Comparisons of the computed solution with velocity
measurements have given good agreement for the mean and turbulent fields. The results enhance evidence of weak turbulence
by comparing the turbulence properties with available data in the literature (Lygren and Andersson, J Fluid Mech 426:297–326,
2001). An approximately self-similar boundary layer behavior is observed along the stator. The wall-normal variations of the structural
parameter and of characteristic angles confirm that this boundary layer is three-dimensional. A quadrant analysis (Kang et
al., Phys Fluids 10:2315–2322, 1998) of conditionally averaged velocities shows that the asymmetries obtained are dominated by Reynolds stress-producing events
in the stator boundary layer. Moreover, Case 1 vortices (with a positive wall induced velocity) are found to be the major
source of generation of special strong events, in agreement with the conclusions of Lygren and Andersson (J Fluid Mech 426:297–326,
2001). |
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Keywords: | Rotor-stator Three-dimensional turbulent boundary layer Direct numerical simulation LDA |
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