11th European Conference on Turbomachinery Fluid dynamics & Thermodynamics

Paper ID:

ETC2015-059

Main Topic:

TURBULENCE MODELLING

Authors

S. Kubacki - Institute of Aeronautics and Applied Mechanics, Warsaw University of Technology, Poland
B. Górecki - Institute of Aeronautics and Applied Mechanics, Warsaw University of Technology, Poland
E. Dick - Department of Flow, Heat and Combustion Mechanics, Ghent University, Belgium

Abstract

A simple algebraic intermittency model is proposed for simulation of laminar to turbulent boundary layer transition under high free-stream turbulence. The intermittency model is combined with the newest version of the κ-ω RANS turbulence model by Wilcox. The transition model takes into account, in an approximate way, two effects in an attached pretransitional boundary layer: damping of short-wavelength disturbances caused by the free stream and breakdown of long-wavelength disturbances inside the boundary layer into finescale turbulence. The transition model uses only local variables. The model has been tuned for the flat plate T3C cases of ERCOFTAC, relevant for bypass transition and tested for flow through cascades of N3-60 (Re=6·105 ) vanes and T106A (Re=1.6·105 ) blades. The transition model produces good results for bypass transition in attached boundary layers far from separation (2D RANS) and prone to separation (2D RANS and 3D URANS). Good results are also obtained for transition in separated laminar boundary layers (3D URANS) thanks to resolution of their instability and the onset of the breakdown

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