Proper orthogonal decomposition and dynamic mode decomposition of jet in channel crossflow

Research output: Contribution to journalArticle

Abstract

The paper is devoted to the application of the model order reduction to the results of direct numerical simulation of a low momentum laminar jet discharged into a laminar channel crossflow through a circular orifice (Reynolds number Re = 3333, jet-to-crossflow velocity ratio is R = 1/6, mesh 13 million nodes, (Wu et al., 2017a)). Main attention is paid to the post-processor analysis of the computational results via model order reduction techniques: the Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) which can drastically reduce the amount of data needed. Up to 400 snapshots, obtained by direct numerical simulation, are used to extract the structures. We study the sensitivity of both algorithms to the sampling frequency and time
span. For the first time different DMD ranking approaches are analysed in the application to a low-dimensional flow reconstruction. It is shown that the DMD approach with the ranking with respect to the amplitudes averaged over time is the most efficient technique for the problem in study. A comparative analysis is also carried out or both POD and DMD. It is shown the energy is more evenly distributed in the DMD. In turn, the POD is quite optimal in reconstructing the flow while the DMD requires more modes to capture the same amount of energy. However, DMD modes automatically reveal the frequency information and corresponding spatial structures in the entire field as well as interactions between different parts of the flow domain.

Bibliographical metadata

Original languageEnglish
Article number344
Pages (from-to)54
Number of pages68
JournalNuclear Engineering and Design 
Volume344
Early online date31 Jan 2019
DOIs
Publication statusPublished - 1 Apr 2019