Dynamic Mode Decomposition of a Separated Nozzle Flow with Transonic Resonance

Lárusson, Ragnar; Andersson, Niklas; Östlund, Jan

doi:10.2514/1.j054876

Cited by 9 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The basis of DMD is the eigen decomposition of a best-fit linear operator that approximates the dynamics present in the data. Specifically in the fluid dynamic application, the DMD method has been shown to be effective in analyzing self-sustained oscillations [52], a dynamic stall [53], forced spatially developed transitional jets [54], an airfoil stall control [55], and nozzle-separated nozzle flow [56]. Pirozzoli et al [57] performed Direct Numerical Simulation on the spatially expanding mixing layer issuing from two turbulent streams in front of a splitter plate, and performed a modal analysis on the results using the DMD.…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of Cavitation Jets from an Organ-Pipe Nozzle: The Influence of Cavitation on the Vortex Coherent Structure

Fang

Hou

et al. 2023

Processes

View full text Add to dashboard Cite

High-speed water jets are widely used in deep mining and the in-depth study of jet characteristics helps to improve drilling efficiency. Three-dimensional Large Eddy Simulation is used to simulate turbulent flows generated by an organ-pipe nozzle. The simulation is validated with existing experimental data and is focused on the evolution and interaction of cavitation bubbles and vortices. Dynamic mode decomposition is performed to extract structural information about the different motion modes and their stability. Results show that the dominant fluid frequency is positively correlated with inlet pressure while unrelated to the divergence angle. Meanwhile, jets’ oscillation is amplified by a large divergence angle, which facilitates the occurrence of cavitation. Results about the flow field outside of an organ-pipe nozzle advance the understanding of the basic mechanism of cavitation jets.

show abstract

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of Cavitation Jets from an Organ-Pipe Nozzle: The Influence of Cavitation on the Vortex Coherent Structure

Fang

Hou

et al. 2023

Processes

View full text Add to dashboard Cite

show abstract

“…An important aspect is, however, that the mechanism appears to be essentially axisymmetric and only the behaviour of the axisymmetric mode was experimentally found to be affected by the transonic resonance. In addition, Lárusson, Andersson & Östlund (2017) have carried out a dynamic mode decomposition (known as DMD) analysis, just based on snapshots obtained from perturbed unsteady Reynolds-averaged Navier–Stokes computations in axisymmetric formulation. These authors have shown that it can already enable the identification of dominant modes and frequencies in fair agreement with the standing wave experimentally observed (Loh & Zaman 2002).…”

Section: Introductionmentioning

confidence: 99%

Jet resonance in truncated ideally contoured nozzles

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Liu and Zhang 30 analyzed the dynamic characteristics of the separated flow around a finite blunt plate based on the DMD modes and the corresponding energy spectra. Lárusson et al 31 conducted a DMD analysis of a separated nozzle flow with transonic resonance to capture the global transonic frequency under different pressure ratios. However, few studies have been conducted for unsteady flow analysis of centrifugal compressors based on the DMD method.…”

Section: Introductionmentioning

confidence: 99%

Dynamic mode decomposition analysis of the flow characteristics in a centrifugal compressor with vaned diffuser

Zhao

Liu

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part A:

View full text Add to dashboard Cite

To understand the flow dynamic characteristics of a centrifugal compressor, the dynamic mode decomposition (DMD) method is introduced to decompose the complex three-dimensional flow field. Three operating conditions, peak efficiency (OP1), peak pressure ratio (OP2), and small mass flow rate (near stall, OP3) conditions, are analyzed. First, the physical interpretations of main dynamic modes at OP1 are identified. As a result, the dynamic structures captured by DMD method are closely associated with the flow characteristics. In detail, the BPF/2BPF (blade passing frequency) corresponds to the impeller–diffuser interaction, the rotor frequency (RF) represents the tip leakage flow (TLF) from leading edge, and the 4RF is related to the interaction among the downstream TLF, the secondary flow, and the wake vortex. Then, the evolution of the dynamic structures is discussed when the compressor mass flow rate consistently declines. In the impeller, the tip leakage vortex near leading edge gradually breaks down due to the high backpressure, resulting in multi-frequency vortices. The broken vortices further propagate downstream along streamwise direction and then interact with the flow structures of 4RF. As a result, the 8RF mode can be observed in the whole impeller, this mode is transformed from upstream RF and 4RF modes, respectively. On the other hand, the broken vortices show broadband peak spectrum, which is correlated to the stall inception. Therefore, the sudden boost of energy ratio of 14RF mode could be regarded as a type of earlier signal for compressor instability. In the diffuser, the flow structures are affected by the perturbation from the impeller. However, the flow in diffuser is more stable than that in impeller at OP1–OP3, since the leading modes are stable patterns of BPF/2BPF.

show abstract

Dynamic Mode Decomposition of a Separated Nozzle Flow with Transonic Resonance

Cited by 9 publications

References 19 publications

Large Eddy Simulation of Cavitation Jets from an Organ-Pipe Nozzle: The Influence of Cavitation on the Vortex Coherent Structure

Large Eddy Simulation of Cavitation Jets from an Organ-Pipe Nozzle: The Influence of Cavitation on the Vortex Coherent Structure

Jet resonance in truncated ideally contoured nozzles

Dynamic mode decomposition analysis of the flow characteristics in a centrifugal compressor with vaned diffuser

Contact Info

Product

Resources

About