An improved throughflow method to treat transonic viscous flows with shocks, using a finite-volume time-marching solver, is presented. Effects due to deviation, secondary losses, endwall skin friction and spanwise mixing are modelled. An alternative blade blockage is used to better take into account the effect of the blade on the transonic passage flow. A theoretical and numerical study of the axisymmetric shock showed that it is treated as a normal blade passage shock by the blade row model. Two different techniques to solve the numerical problems associated with the leading edge singularity due to incidence are investigated. The computation of an entire speed-line for a three stage transonic fan has been conducted in order to further calihrate and validate the various models. The validation showed that the solver is capable of giving a reasonable meridional picture of the transonic flow field for different operating points.

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Two three-dimensional Reynolds-averaged Navier-Stokes solutions of the Nasa 67 transonic compressor rotor with tip clearance, computed at near-peak efficiency and near-stall flow conditions, have been circumferentially averaged in order to evaluate the circumferential spatial fluctuation terms such as u′u′, u′v′, u′w′, etc. The three-dimensional distribution of these fluctuations is presented and physically interpreted for the two flow conditions. Then, the meridional distributions of the tangential average of each of these fluctuation terms, the so-called perturbation stresses, are described and interpreted for the two flow conditions. A meridional throughflow computation for which all stresses were included has been performed for the near-peak efficiency flow condition using a time-marching finite-volume solver. The calculation proved to be in good agreement with the tangentially averaged 3D solution. Moreover, the relative importance of the perturbation and viscous stresses has been investigated. The influence of the viscous stresses on the meridional flow was not found important whereas the perturbation stresses were identified as significant contributors to the blade passage losses and to the spanwise mixing phenomenon. Furthermore, the relative effects of each perturbation term on the meridional flow prediction have been investigated for the near-peak efficiency case. The u′w′~, v′w′~, u′v′~ and u′u′~ stresses proved to exert a significant influence on the prediction of blade design key parameters such as flow angles and losses in the tip region, essentially.

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