Vector visibility graph from multivariate time series: a new method for characterizing nonlinear dynamic behavior in two-phase flow

2019 ◽  
Vol 97 (4) ◽  
pp. 2547-2556 ◽  
Author(s):  
Weikai Ren ◽  
Ningde Jin
Keyword(s):  
Time Series ◽  
Dynamic Behavior ◽  
Nonlinear Dynamic ◽  
Two Phase Flow ◽  
Multivariate Time Series ◽  
Visibility Graph ◽  
New Method ◽  
Phase Flow ◽  
Two Phase ◽  
Nonlinear Dynamic Behavior

scholarly journals Complex networks from multivariate time series for characterizing nonlinear dynamics of two-phase flow patterns

2012 ◽  
Vol 61 (12) ◽  
pp. 120510
Author(s):  
Gao Zhong-Ke ◽  
Jin Ning-De ◽  
Yang Dan ◽  
Zhai Lu-Sheng ◽  
Du Meng
Keyword(s):  
Nonlinear Dynamics ◽  
Time Series ◽  
Complex Networks ◽  
Two Phase Flow ◽  
Multivariate Time Series ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase

scholarly journals Clustering-Based Component Fraction Estimation in Solid–Liquid Two-Phase Flow in Dredging Engineering

Sensors ◽  
2020 ◽  
Vol 20 (19) ◽  
pp. 5697
Author(s):  
Chang Sun ◽  
Shihong Yue ◽  
Qi Li ◽  
Huaxiang Wang
Keyword(s):  
Clustering Algorithm ◽  
Two Phase Flow ◽  
Low Cost ◽  
Fast Response ◽  
New Method ◽  
Phase Flow ◽  
Reference Distribution ◽  
Two Phase ◽  
Long Time ◽  
Solid Liquid

Component fraction (CF) is one of the most important parameters in multiple-phase flow. Due to the complexity of the solid–liquid two-phase flow, the CF estimation remains unsolved both in scientific research and industrial application for a long time. Electrical resistance tomography (ERT) is an advanced type of conductivity detection technique due to its low-cost, fast-response, non-invasive, and non-radiation characteristics. However, when the existing ERT method is used to measure the CF value in solid–liquid two-phase flow in dredging engineering, there are at least three problems: (1) the dependence of reference distribution whose CF value is zero; (2) the size of the detected objects may be too small to be found by ERT; and (3) there is no efficient way to estimate the effect of artifacts in ERT. In this paper, we proposed a method based on the clustering technique, where a fast-fuzzy clustering algorithm is used to partition the ERT image to three clusters that respond to liquid, solid phases, and their mixtures and artifacts, respectively. The clustering algorithm does not need any reference distribution in the CF estimation. In the case of small solid objects or artifacts, the CF value remains effectively computed by prior information. To validate the new method, a group of typical CF estimations in dredging engineering were implemented. Results show that the new method can effectively overcome the limitations of the existing method, and can provide a practical and more accurate way for CF estimation.

Non-Linear Time Series Analysis of the Infuence of Rolling Motion on Natural Circulation System

2010 ◽  
Author(s):  
Wenchao Zhang ◽  
Sichao Tan ◽  
Puzhen Gao
Keyword(s):  
Experimental Data ◽  
Time Series ◽  
Time Series Analysis ◽  
Two Phase Flow ◽  
Flow Instability ◽  
Natural Circulation ◽  
Rolling Motion ◽  
Phase Flow ◽  
Two Phase ◽  
Series Analysis

Two-phase natural circulation flow instability under rolling motion condition was studied experimentally and theoretically. Experimental data were analyzed with nonlinear time series analysis methods. The embedding dimension, correlation dimension and K2 entropy were determined based on phase space reconstruction theory and G-P method. The maximal Lyapunov exponent was calculated according to the methods of small data sets. The nonlinear features of the two phase flow instability under rolling motion were analyzed with the results of geometric invariants coupling with the experimental data. The results indicated that rolling motion strengthened the nonlinear characteristics of two phase flow instability. Some typical nonlinear phenomena such as period-doubling bifurcations and chaotic oscillations were found in different cases.

scholarly journals Detection of Two-Phase Flow Patterns in a Vertical Minichannel Using the Recurrence Quantification Analysis

2015 ◽  
Vol 9 (2) ◽  
pp. 99-104
Author(s):  
Romuald Mosdorf ◽  
Grzegorz Górski
Keyword(s):  
Time Series ◽  
Two Phase Flow ◽  
Bubbly Flow ◽  
Flow Patterns ◽  
Recurrence Quantification Analysis ◽  
Phase Flow ◽  
Two Phase ◽  
Signal Characteristics ◽  
Recurrence Quantification ◽  
Quantification Analysis

Abstract The two-phase flow (water-air) occurring in square minichannel (3x3 mm) has been analysed. In the minichannel it has been observed: bubbly flow, flow of confined bubbles, flow of elongated bubbles, slug flow and semi-annular flow. The time series recorded by laser-phototransistor sensor was analysed using the recurrence quantification analysis. The two coefficients:Recurrence rate (RR) and Determinism (DET) have been used for identification of differences between the dynamics of two-phase flow patterns. The algorithm which has been used normalizes the analysed time series before calculating the recurrence plots.Therefore in analysis the quantitative signal characteristicswas neglected. Despite of the neglect of quantitative signal characteristics the analysis of its dynamics (chart of DET vs. RR) allows to identify the two-phase flow patterns. This confirms that this type of analysis can be used to identify the two-phase flow patterns in minichannels.

Identification of two phase flow regimes via diffusional analysis of experimental time series

1996 ◽  
Vol 21 (3) ◽  
pp. 151-160 ◽  
Author(s):  
A. Soldati ◽  
A. Paglianti ◽  
M. Giona
Keyword(s):  
Time Series ◽  
Two Phase Flow ◽  
Flow Regimes ◽  
Phase Flow ◽  
Two Phase ◽  
Experimental Time ◽  
Experimental Time Series

scholarly journals Theoretical Study on the Dynamic Behavior of Pipes Conveying Gas-Liquid Flow

2018 ◽  
Vol 148 ◽  
pp. 01004
Author(s):  
L. Enrique Ortiz-Vidal ◽  
David G. Castillo ◽  
Quino Valverde
Keyword(s):  
Dynamic Behavior ◽  
Two Phase Flow ◽  
Homogeneous Model ◽  
Beam Theory ◽  
Equation Of Motion ◽  
Phase Flow ◽  
Order Partial Differential Equation ◽  
Flow Conditions ◽  
Two Phase ◽  
System Frequency

The dynamic behavior of clamped-clamped straight pipes conveying gas-liquid two-phase flow is theoretically investigated, specifically the effect of the flow parameters on the frequency of the system. First, the equation of motion is derived based on the classic Païdoussis formulation. Assuming Euler-Bernoulli beam theory, small-deflection approximation and no-slip homogeneous model, a coupled fluid-structure fourth-order partial differential equation (PDE) is obtained. Then, the equation of motion is rendered dimensionless and discretized through Galerkin’s method. That method transforms the PDE into a set of Ordinary Differential Equations (ODEs). The system frequency is obtained by solving the system of ODEs by allowing the determinant to be equal to zero. System frequencies for different geometries, structural properties and flow conditions have been calculated. The results show that the system frequency decreases with increasing two-phase flow velocity. By contrast, the former increases with increasing homogeneous void fraction. These theoretical results are in agreement with experimental findings reported in the literature. Furthermore, even for typical two phase flow conditions, the system can become unstable for inadequate chooses of geometry or material of the pipe.

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