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Simulation and modelling of turbulent trailing-edge flow

Yao, Yufeng; Savill, A. M.; Sandham, N. D.; Dawes, W. N.

Authors

Yufeng Yao Yufeng.Yao@uwe.ac.uk
Professor in Aerospace Engineering

A. M. Savill

N. D. Sandham

W. N. Dawes



Abstract

Computations of turbulent trailing-edge flow have been carried out at a Reynolds number of 1000 (based on the free-stream quantities and the trailing-edge thickness) using an unsteady 3D Reynolds-Averaged Navier-Stokes (URANS) code, in which two-equation (k-ε) turbulence models with various low-Re near wall treatments were implemented. Results from a direct numerical simulation (DNS) of the same flow are available for comparison and assessment of the turbulence models used in the URANS code. Two-dimensional URANS calculations are carried out with turbulence mean properties from the DNS used at the inlet; the inflow boundary-layer thickness is 6.42 times the trailing-edge thickness, close to typical turbine blade flow applications. Many of the key flow features observed in DNS are also predicted by the modelling; the flow oscillates in a similar way to that found in bluff-body flow with a von Kármán vortex street produced downstream. The recirculation bubble predicted by unsteady RANS has a similar shape to DNS, but with a length only half that of the DNS. It is found that the unsteadiness plays an important role in the near wake, comparable to the modelled turbulence, but that far downstream the modelled turbulence dominates. A spectral analysis applied to the force coefficient in the wall normal direction shows that a Strouhal number based on the trailing-edge thickness is 0.23, approximately twice that observed in DNS. To assess the modelling approximations, an a priori analysis has been applied using DNS data for the key individual terms in the turbulence model equations. A possible refinement to account for pressure transport is discussed.

Journal Article Type Article
Publication Date Dec 1, 2002
Journal Flow, Turbulence and Combustion
Print ISSN 1386-6184
Publisher Springer Verlag
Peer Reviewed Peer Reviewed
Volume 68
Issue 4
Pages 313-333
DOI https://doi.org/10.1023/A%3A1021755327045
Keywords turbulence modelling, direct numerical simulation, trailing-edge flow
Public URL https://uwe-repository.worktribe.com/output/1084359
Publisher URL http://dx.doi.org/10.1023/A:1021755327045