Development and validation of Navier–Stokes characteristic boundary conditions applied to turbomachinery simulations using the lattice Boltzmann method

Abstract

AbstractThis article reports a procedure to implement as well as to validate non‐reflecting boundary conditions applied for turbomachinery simulations, using Navier–Stokes characteristic boundary conditions in a compressible lattice Boltzmann solver. The implementation of both an inlet condition imposing total pressure, total temperature, and flow angles, as well as an outlet condition imposing a static pressure profile that allows the simulation to reach a simplified radial equilibrium, is described within the context of a lattice Boltzmann approach. The treatment at the boundaries relies on the characteristic methodology to derive conditions which are non‐reflecting in terms of acoustics and is also compatible with turbulence injection at the inlet. These properties are evaluated on test cases of increasing complexity, ranging from a simple 2D periodic domain to an S‐duct stage with turbulence injection.