Rotating turbulent flows
Rotating turbulent flows are ubiquitous in geophysics, astrophysics and engineering. Consider, for example, flows in the oceans, in the atmosphere or in turbomachinery. Understanding and being able to predict the behavior of such flows is of great importance for many applications. However, despite the increased fundamental understanding, predicting rotating turbulent flows remains a challenge. This is mainly because such flows often contain a large range of scales of motion, which cannot be resolved using direct numerical simulations. With the aim to improve the numerical prediction of incompressible rotating turbulent flows, we, therefore, turn to large-eddy simulation.
In large-eddy simulation, the large scales of motion in a flow are explicitly computed, whereas the effects of the small-scale motions are modeled using subgrid-scale models. Eddy viscosity models are commonly used subgrid-scale models. These subgrid-scale models prescribe the net dissipation of kinetic energy caused by small-scale turbulent motions. Although eddy viscosity models are effective in many cases, they have an important drawback. They model turbulence as an essentially dissipative process. Given the importance of energy transfer in rotating turbulent flows, it seems unlikely that eddy viscosity models are always suitable for large-eddy simulations of such flows.
In this project, we, therefore, propose a new subgrid-scale model for large-eddy simulations of incompressible rotating turbulent flows. This subgrid-scale model consists of a dissipative eddy viscosity term as well as a nondissipative term that is nonlinear in the rate-of-strain and rate-of-rotation tensors. We study and validate this subgrid-scale model using detailed direct numerical and large-eddy simulations of two canonical rotating turbulent flows, namely, rotating decaying turbulence and spanwise-rotating plane-channel flow. We also provide a comparison with the commonly used dynamic Smagorinsky model, the scaled anisotropic minimum-dissipation model and the vortex-stretching-based eddy viscosity model.
Silvis, M. H., Bae, H. J., Trias, F. X., Abkar, M., Verstappen, R. (2019). “A nonlinear subgrid-scale model for large-eddy simulations of rotating turbulent flows”. arXiv: 1904.12748 [physics.flu-dyn]. Abstract PDF BibTeX BibLaTeX Cited by 2+
Silvis, M. H., Verstappen, R. (2019). “Nonlinear Subgrid-Scale Models for Large-Eddy Simulation of Rotating Turbulent Flows”. In: Direct and Large-Eddy Simulation XI. Ed. by Salvetti, M. V., Armenio, V., Fröhlich, J., Geurts, B. J., Kuerten, H. Springer International Publishing, pp. 129–134. DOI: 10.1007/978-3-030-04915-7_18. Abstract PDF BibTeX BibLaTeX Cited by 5+
Silvis, M. H., Trias, F. X., Abkar, M., Bae, H. J., Lozano-Durán, A., Verstappen, R. W. C. P. (2016). “Exploring nonlinear subgrid-scale models and new characteristic length scales for large-eddy simulation”. In: Studying Turbulence Using Numerical Simulation Databases - XVI: Proceedings of the 2016 Summer Program. Ed. by Moin, P., Urzay, J. Center for Turbulence Research, Stanford University, pp. 265–274. Abstract PDF BibTeX BibLaTeX Cited by 12+
Physics-based turbulence models
The Navier–Stokes equations form a very accurate mathematical model for turbulent flows. The behavior of most turbulent flows can, however, not (yet) directly be predicted using these equations, because the current computational power does not suffice to resolve all physically relevant scales of motion in such flows. We, therefore, turn to large-eddy simulation to predict the large-scale behavior of incompressible turbulent flows. In large-eddy simulation, the large scales of motion in a flow are explicitly computed, whereas effects of small-scale motions have to be modeled. Here, the question is: how to model these effects? Moreover, one can wonder: what defines a well-designed subgrid-scale model?
In this project, we aim to answer these questions by following a systematic approach, based on the idea that subgrid-scale models should respect the fundamental physical and mathematical properties of the Navier–Stokes equations and the turbulent stresses. We thereby obtain a framework of constraints for the construction of physics-based subgrid-scale models. We apply this framework to a general class of subgrid-scale models based on the local velocity gradient. We also analyze the properties of a number of existing models from this class. Finally, we illustrate how new physics-based subgrid-scale models with desired built-in properties can be created.
Silvis, M. H., Remmerswaal, R. A., Verstappen, R. (2017). “Physical consistency of subgrid-scale models for large-eddy simulation of incompressible turbulent flows”. Physics of Fluids 29, 015105. DOI: 10.1063/1.4974093. Abstract PDF BibTeX BibLaTeX Cited by 34+
Silvis, M. H., Remmerswaal, R. A., Verstappen, R. (2017). “A Framework for the Assessment and Creation of Subgrid-Scale Models for Large-Eddy Simulation”. In: Progress in Turbulence VII: Proceedings of the iTi Conference in Turbulence 2016. Ed. by Örlü, R., Talamelli, A., Oberlack, M., Peinke, J. Springer International Publishing, pp. 133–139. DOI: 10.1007/978-3-319-57934-4_19. Abstract PDF BibTeX BibLaTeX Cited by 2+
Silvis, M. H., Verstappen, R. (2018). “Constructing Physically Consistent Subgrid-Scale Models for Large-Eddy Simulation of Incompressible Turbulent Flows”. In: Turbulence and Interactions: Proceedings of the TI 2015 Conference. Ed. by Deville, M. O., Couaillier, V., Estivalezes, J.-L., Gleize, V., Lê, T.-H., Terracol, M., Vincent, S. Springer International Publishing, pp. 241–247. DOI: 10.1007/978-3-319-60387-2_26. Abstract PDF BibTeX BibLaTeX Cited by 3+
Silvis, M. H., Verstappen, R. (2015). “Physically-consistent subgrid-scale models for large-eddy simulation of incompressible turbulent flows”. arXiv: 1510.07881 [physics.flu-dyn]. Abstract PDF BibTeX BibLaTeX Cited by 4+