Turbulence modelling and turbulent inlet on a blunt plate: a numerical study

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Abstract

Free Stream Turbulence is usually disregarded as a governing parameter in the assessment of aerodynamic forces. However, an effect is noticeable on the aerodynamic coefficients if turbulence is added at the inlet. In this work, the performance of different sub-grid scale (SGS) models of large-eddy simulation (LES) is investigated against their capability to describe the separation bubble of a blunt plate under a turbulent inlet. This is aimed at starting a broader research on the actual role of turbulence on the aerodynamic behaviour. Together with the Smagorinsky, the dynamic and the WALE SGS models, also the URANS "k-ε" and "k-" ω SST have been compared. The results show that whether URANS is able to accurately describe the undisturbed case, it gives a wrong turbulent inlet in the other one. Although the LES technique can improve the accuracy of this complex configuration, the choice of a suitable averaging time strongly affects the validation of the model. It was found that the role of the SGS eddies is not preponderant. Then a complex system of equations may lead to instability of the solver and prohibitive time step requirements. Among the SGS models investigated, the Smagorinsky SGS model, using a damping function to tackle the near-wall behaviour, qualifies then as a good candidate for further, more complex, geometries

Details

Original languageEnglish
Title of host publicationProceedings of the XIV Conference of the Italian Association for Wind Engineering - IN-VENTO 2016
EditorsAnnibale Luigi Materazzi, Ilaria Venanzi
Publication statusPublished - 2018
EventXIV Conference of the Italian Association for Wind Engineering - Terni, Italy
Duration: 25 Sep 201628 Sep 2016

Conference

ConferenceXIV Conference of the Italian Association for Wind Engineering
Abbreviated titleIN-VENTO 2016
CountryItaly
CityTerni
Period25/09/1628/09/16