Numerical investigation of draft tube flows using a hybrid RANS-LES turbulence model and a low-dissipation scheme. Issue 7 (March 2019)

• Record Type: Journal Article
• Authors: Jiang, Y; Liu, Y; Nadarajah, S
• Is Part Of: IOP conference series. Volume 240:Issue 7(2019)
• Publication Date: 2019-03
• Subjects: Earth sciences -- Periodicals; Environmental sciences -- Congresses; Environmental sciences -- Periodicals; 550.5
• DOI: 10.1088/1755-1315/240/7/072011
• Languages: English
• ISSNs: 1755-1307

Abstract

Abstract: Hydro-turbines are operated at loads above or below the best efficiency point (over- or part-load), where turbulent flow structures are formed in the draft tube. The goal of the project is to investigate complex turbulent structures present in the draft tube through a thorough numerical investigation. In the context of numerical simulations, a focus is made on the turbulence model and the numerical scheme. Transient simulations with the k- ω SST and SAS (Scale Adaptive Simulation)-SST turbulence models are applied with a novel eddy-preserving limiter scheme for draft tube flows. The application of both the SAS-SST turbulence model and the eddy-preserving limiter scheme allows for the resolution of more turbulent structures. The impact of the inlet modification is also studied. Numerical results are validated through a comparison to experimental data for the BulbT test case.