SCALE-RESOLVING SIMULATIONS OF TURBULENT FLOW RETAINING THE EXACT BLADE COUNT WITH THE TIME-INCLINED METHOD

Abstract Simulations of the T106 low-pressure turbine linear cascade with incoming wakes have been conducted to demonstrate the suitability of the time-inclined method for retaining the exact blade count in scale-resolving simulations. The time-inclined method has been implemented into a high-order unstructured time-marching code based on the flux-reconstruction method. The pitch ratio between the upstream incoming wakes and the cascade is not a small integer, and the time-inclined method is used to reduce the simulations to a single-passage computational domain. Three-way comparisons have been generated: the solution of the direct periodic full domain, spanning several blade passages, is compared to the single-passage time-inclined solution and to a single-passage solution that approximates the pitch ratio to the nearest integer. Two sets of virtual experiments, which differ in modelling of the incoming perturbations, are reported. Firstly, the immersed boundary approach is used to introduce a cascade of moving bars that act as the trailing edges of the preceding row and generate incoming wakes. The second set of simulations introduces wake-like perturbations at the inlet section of the computational domain. The present work shows that the time-inclined method, retaining the exact blade count, can produce very accurate results for turbulence-resolving simulations. Moreover, the time-inclined method outperforms the standard single-passage methodology in most of the variables of interest and is equivalent in the rest.