A novel Omega-driven dynamic PANS model
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Available online at https://link.springer.com/journal/42241 http://www.jhydrodynamics.com Journal of Hydrodynamics, 2020, 32(4): 710-716 https://doi.org/10.1007/s42241-020-0052-y
A novel Omega-driven dynamic PANS model * Chao-yue Wang1, Fu-jun Wang1, 2, Ben-hong Wang1, Yuan Tang1, Hao-ru Zhao1 1. College of Water Resources and Civil Engineering, China Agricultural University, Beijing 100083, China 2. Beijing Engineering Research Center of Safety and Energy Saving Technology for Water Supply Network System, Beijing 100083, China (Received January 16, 2020, Revised March 4, 2020, Accepted March 11, 2020, Published online August 26, 2020) ©China Ship Scientific Research Center 2020 Abstract: A novel Omega ( ) -driven dynamic partially-averaged Navier-Stokes (PANS) model is proposed in this paper. The ratio of the modeled-to-total turbulent kinetic energies f k is dynamically adjusted by the rigid vorticity ratio (the ratio of the rigid vorticity to the total vorticity), the key parameter of the vortex identification method. Three classical flow cases with rotation and curvature are used to test the model. The results show that the turbulent viscosity is effectively adjusted by the new dynamic f k and the LES-like mode is activated, which can help the revelation of more turbulence information and improve the prediction accuracy. The new PANS model does not contain any explicit dependency on the grid size and enjoys good adaptability to the flow fields, and can be used for efficient engineering computations of the turbulent flows in the hydraulic machinery. Key words: Dynamic partially-averaged Navier-Stokes (PANS), turbulence model, Omega, engineering computations
Introduction The partially-averaged Navier-Stokes (PANS) model was proposed by Girimaji et al.[1] as a second generation URANS approach to resolve the substantial part of the turbulent structures. For high Reynolds number flows, the PANS model can switch from the URANS mode to the LES-like mode where the ratio of the modeled-to-total turbulent kinetic energies f k is reduced yielding a lower turbulent viscosity with high fluctuations[2-3], and it is also easy to be implanted into the existing URANS solver. The original PANS model is developed assuming that f k takes a fixed value, and it is extensively used in many turbulent separation flow cases, such as the flow over a backward facing step[4], the flow past a square or circular cylinder[5-6], the cavitating flow around a hydrofoil[7], and the swirling flows in the * Project supported by the National Natural Science Foundation of China (Grant Nos. 51836010, 51779258 and 51839001), the National Key Research and Development Program of China (Grant No. 2018YFB0606103) and the Nature Science Foundation of Beijing (Grnat No. 3182018). Biography: Chao-yue Wang (1993-), Male, Ph. D. Candidate, E-mail: [email protected] Corresponding author: Fu-jun Wang, E-mail: [email protected]
pumps and turbines[8-9]. However, to remedy the assumption of the constant f k , the PANS model is gradually extended to the c
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