A hybrid RANS model of wing-body junction flow

The three-dimensional flow separation over the Rood wing-body junction is an exemplar application of separation affecting many important flows in turbomachinery and aerodynamics. Conventional Reynolds Averaged Navier Stokes (RANS) methods struggle to reproduce the complexity of this flow. In this paper, an unconventional use is made of a hybrid Reynolds Averaged Navier Stokes (RANS) model to tackle this challenge. The hybridization technique combines the Menter 𝑘𝑘 − 𝜔𝜔 − 𝑆𝑆𝑆𝑆𝑆𝑆 model with the one equation sub-grid-scale (SGS) model by Yoshizawa through a blending function, based on the wall-normal distance. The hybrid RANS turbulence closure captured most of the flow features reported in past experiments with reasonable accuracy. The model captured also the small secondary vortex at the corner ahead of the wing nose and at the trailing edge. This feature is scarcely documented in the literature. The study highlights the importance of the spatial resolution near the wing leading edge, where this localised secondary recirculation was observed by the hybrid RANS model. It also provides evidence on the applicability of the hybrid Menter and Yoshizawa turbulence closure to the wing-body junction flows in aircraft and turbomachines, where the flows are characterised by a substantially time-invariant three-dimensional separation.