期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2019
卷号：240
期号：7
页码：1-11
DOI：10.1088/1755-1315/240/7/072026
出版社：IOP Publishing
摘要：The instability of stationary vortex structures is manifested by an oscillation at several fundamental frequencies which are associated with characteristic shapes. It is caused by the non-linear convective terms in the Navier-Stokes equations. The frequency of unstable oscillation can be detected by the Fourier transform of the velocity and the pressure field themselves or their constitutive modes. It is this knowledge of the constitutive modes that is the basis for using the inverse method to define a reduced mathematical model in a finite-dimensional space. This model allows to analyze the vortex structures in the region of instability and their dependence on inhomogeneous boundary conditions. Present paper describes the essential steps of deriving an inverse method. The inverse method is applied to fluid flow in the draft tube of a swirl generator. The dynamic mode decomposition and the discrete Fourier transform of the flow field are assessed as possible methods that can provide the modal and spectral matrix for the model.
