Mesh Resolution Effect on 3D RANS Turbomachinery Flow Simulations

TL;DR

This study investigates how mesh refinement impacts the accuracy of 3D RANS turbomachinery flow simulations, highlighting the need for very fine meshes for detailed analysis and more moderate meshes for industrial purposes.

Contribution

It provides a systematic analysis of mesh resolution effects on 3D turbomachinery flow simulations using a second-order ENO scheme and multigrid methods.

Findings

Finer meshes improve flow pattern resolution.

Mesh sizes of several million cells are recommended for detailed studies.

Industrial applications can use meshes with around one million cells.

Abstract

The paper presents the study of the effect of a mesh refinement on numerical results of 3D RANS computations of turbomachinery flows. The CFD solver F, which based on the second-order accurate ENO scheme, is used in this study. The simplified multigrid algorithm and local time stepping permit decreasing computational time. The flow computations are performed for a number of turbine and compressor cascades and stages. In all flow cases, the successively refined meshes of H-type with an approximate orthogonalization near the solid walls were generated. The results obtained are compared in order to estimate their both mesh convergence and ability to resolve the transonic flow pattern. It is concluded that for thorough studying the fine phenomena of the 3D turbomachinery flows, it makes sense to use the computational meshes with the number of cells from several millions up to several hundred millions per a single turbomachinery blade channel, while for industrial computations, a mesh of about or less than one million cells per a single turbomachinery blade channel could be sufficient under certain conditions.