Large-eddy simulation of turbulent pipe flow of Herschel-Bulkley fluids - Assessing subgrid-scale models

• Published in: Computers & fluids Vol. 244; p. 105522
• Main Authors: Basso, Felipe O., Franco, Admilson T., Pitz, Diogo B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.08.2022
• Subjects: Generalized Newtonian fluid (GNF); Large-eddy simulation (LES); OpenFOAM; Subgrid-scale (SGS) models; Turbulent pipe flow; Large-eddy simulation (LES); Subgrid-scale (SGS) models; Generalized Newtonian fluid (GNF); OpenFOAM; Turbulent pipe flow
• ISSN: 0045-7930; 1879-0747
• DOI: 10.1016/j.compfluid.2022.105522

•LES of non-Newtonian turbulent pipe flow with the viscosity described by the herschel-bulkley model and shear-thinning behavior were performed.•Simulations were carried out with the dynamic smagorinsky and WALE models, and the UDNS at two different generalized reynolds numbers of 5000 and 7500. The results were compared with DNS data available in the literature.•Results obtained with LES and UDNS are in good agreement with the DNS data for first- and second-order turbulence statistics and several flow features. This paper investigates the turbulent pipe flow of viscoplastic fluids using large-eddy simulation (LES) and the OpenFOAM package. The Herschel-Bulkley model is employed to describe the viscosity function with shear-thinning and viscoplastic behavior. Many LES studies evaluating different subgrid-scale (SGS) models for Newtonian fluids are available in the literature. However, studies regarding LES and SGS models involving non-Newtonian fluids are scarce, despite the importance of the subject. The present paper focuses on evaluating the performance of the Dynamic Smagorinsky and Wall Adapting Local Eddy-viscosity (WALE) models, and the under-resolved direct numerical simulation (UDNS) with viscoplastic fluids. The first- and second-order turbulence statistics and flow features, such as mean wall shear stress, mean wall viscosity, friction factor, mean shear rate, and mean viscosity profiles are used to assess the different models. Simulations are carried out at two different generalized Reynolds numbers (ReG) of 5000 and 7500. The numerical results computed with LES are compared with direct numerical simulation (DNS) results and experimental data for turbulent pipe flow of a Newtonian fluid to validate the numerical method. LES results for the Herschel-Bulkley fluid show a good agreement for the first- and second-order turbulence statistics compared with DNS data. Moreover, mean flow quantities obtained with LES follow the trend of DNS data.