Print Email Facebook Twitter Effectivity and efficiency of selective frequency damping for the computation of unstable steady-state solutions Title Effectivity and efficiency of selective frequency damping for the computation of unstable steady-state solutions Author Casacuberta Puig, J. (TU Delft Aerodynamics) Groot, K.J. (TU Delft Aerodynamics) Tol, H.J. (TU Delft Control & Simulation) Hickel, S. (TU Delft Aerodynamics) Date 2018-12-15 Abstract Selective Frequency Damping (SFD) is a popular method for the computation of globally unstable steady-state solutions in fluid dynamics. The approach has two model parameters whose selection is generally unclear. In this article, a detailed analysis of the influence of these parameters is presented, answering several open questions with regard to the effectiveness, optimum efficiency and limitations of the method. In particular, we show that SFD is always capable of stabilising a globally unstable systems ruled by one unsteady unstable eigenmode and derive analytical formulas for optimum parameter values. We show that the numerical feasibility of the approach depends on the complex phase angle of the most unstable eigenvalue. A numerical technique for characterising the pertinent eigenmodes is presented. In combination with analytical expressions, this technique allows finding optimal parameters that minimise the spectral radius of a simulation, without having to perform an independent stability analysis. An extension to multiple unstable eigenmodes is derived. As computational example, a two-dimensional cylinder flow case is optimally stabilised using this method. We provide a physical interpretation of the stabilisation mechanism based on, but not limited to, this Navier–Stokes example. Subject Computational fluid dynamicsFlow controlFlow stability analysisSelective frequency damping To reference this document use: http://resolver.tudelft.nl/uuid:9d21bc81-cb8c-4751-bd5f-45ead988c8dd DOI https://doi.org/10.1016/j.jcp.2018.08.056 Embargo date 2020-09-12 ISSN 0021-9991 Source Journal of Computational Physics, 375, 481-497 Part of collection Institutional Repository Document type journal article Rights © 2018 J. Casacuberta Puig, K.J. Groot, H.J. Tol, S. Hickel Files PDF casacuberta_etal_2018.pdf 775.86 KB Close viewer /islandora/object/uuid:9d21bc81-cb8c-4751-bd5f-45ead988c8dd/datastream/OBJ/view