Calculation of transition in turbine cascades by conditioned Navier-Stokes equations

Abstract

To simulate transitional heat transfer in turbine cascades, the conditionally averaged Navier-Stokes equations are used. To cover both the physics of free-stream turbulence and the intermittent flow behaviour during transition, a turbulence weighting factor τ is introduced. A transport equation is presented for this τ factor including convection, diffusion, production and sink terms. In combination with the conditioned Navier-Stokes equations, this leads to improvements in the calculation of flow characteristics in both the transitional layer and the free stream. The method is validated on transitional heat transfer measurements in a linear turbine cascade at typical operational conditions.