Proper Orthogonal Decomposition as a technique for identifying two-phase flow pattern based on electrical impedance tomography

Collecting of very large amount of data from experimental measurement is a common practice in almost every scientific domains. There is a great need to have specific techniques capable of extracting synthetic information, which is essential for understanding and modelling the specific phenomena. The Proper Orthogonal Decomposition (POD) is one of the most powerful data analysis methods for multivariate and nonlinear phenomena. Generally, POD is a procedure that takes a given collection of input experimental or numerical data and creates an orthogonal basis constituted by functions estimated as the solutions of an integral eigenvalue problem known as a Fredholm equation. This paper proposes a novel approach by utilising POD to identify flow structure in horizontal pipeline, specially, for slag, plug and wavy stratified air-water flow regimes, , in which POD technique extends the current evaluation procedure of electrical impedance tomography [31]. This capability is extended by the implementation of POD as an identifier for typical horizontal two phase flow regimes. Direct POD method introduced by Lumley and Snapshot POD method introduced by Sirovich are applied The POD snapshot matrices are reconstructed from electrical tomography measurement under specific flow conditions. It is expected that this study may provide new knowledge on two phase flow dynamics in a horizontal pipeline and useful information for further prediction of multiphase flow regime.