Proper orthogonal decomposition analysis of the flow field in a plane jet

Shim, Young-Min; Sharma, Rajnish N.; Richards, P.J.

doi:10.1016/j.expthermflusci.2013.06.014

Cited by 43 publications

(15 citation statements)

References 68 publications

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“…For churn flow at z = 3.0 m, εD U 3 increased only slightly in comparison with that at z = 1.0 m. However, for bubbly flow, the value of εD U 3 more than doubled at z = 3.0 m in comparison to z = 1.0 m, which is consistent with the literature (Griffiths, 2012). Thus, at z = 3.0 m, the normalized total energy dissipation rate for churn flow was around 2.5 times that of bubbly flow, which is consistent with the ratio of 2.0 of maximum streamwise turbulence intensities between churn flow and bubbly flow ( Figure S8) (Iqbal & Thomas, 2007;Poole & Hall, 2014;Rahai & Wong, 2002;Shim et al, 2013).…”

Section: Resultssupporting

confidence: 89%

Was the Deepwater Horizon Well Discharge Churn Flow? Implications on the Estimation of the Oil Discharge and Droplet Size Distribution

Boufadel

Gao

Zhao

et al. 2018

Geophysical Research Letters

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Improved understanding of the character of an uncontrolled pipeline flow is critical for the estimation of the oil discharge and droplet size distribution both essential for evaluating oil spill impact. Measured oil and gas properties at the wellhead of the Macondo255 and detailed numerical modeling suggested that the flow within the pipe could have been “churn,” whereby oil and gas tumble violently within the pipe and is different from the bubbly flow commonly assumed for that release. The churn flow would have produced 5 times the energy loss in the pipe compared to bubbly flow, and its plume would have entrained 35% more water than that of the bubbly flow. Both findings suggest that the oil discharge in Deepwater Horizon could have been overestimated, by up to 200%. The resulting oil droplet size distribution of churn flow is likely smaller than that of bubbly flow.

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Section: Resultssupporting

confidence: 89%

Was the Deepwater Horizon Well Discharge Churn Flow? Implications on the Estimation of the Oil Discharge and Droplet Size Distribution

Boufadel

Gao

Zhao

et al. 2018

Geophysical Research Letters

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“…For flow dynamics dominated by large-scale structures, the turbulence statistics can be reconstructed satisfactorily with the first few modes obtained from the POD technique. The POD technique has been applied to a wide range of flows including bar racks in open channel (Tsikata, Tachie, & Katopodis, 2014), free jets (Meyer, Pedersen, & Ozcan, 2007;Shim, Sharm, & Richards, 2013) and 3D wall jets (Agelinchaab &Tachie, 2011a). The results by Shim et al (2013) revealed symmetric counter-rotating vortices within the initial region of the jet.…”

Section: Introductionmentioning

confidence: 96%

Experimental study of the flow structures of 3D turbulent offset jets

Nyantekyi-Kwakye

Tachie

Clark

et al. 2015

Journal of Hydraulic Research

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Three-dimensional turbulent offset jets were investigated using a particle image velocimetry technique. Detailed measurements were performed for offset height ratios of 0, 2 and 4. The presence of backflow influenced the distribution of the mean velocity and Reynolds stresses. A two-point correlation analysis was used to investigate the spatial distribution of large-scale structures within the inner shear layer of the flow domain. The results revealed that large-scale structures dominate the inner layer of the self-similarity region. Proper orthogonal decomposition was performed on the fluctuating velocity field within the symmetry and lateral planes using the snapshot approach. Results from the reconstructed field provided insight into the contributions of the most energetic structures to the turbulence statistics. The energetic structures contributed more to the Reynolds shear stress and streamwise turbulence intensity, while contributing less to the wall-normal turbulence intensity.

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“…The proper orthogonal decomposition (POD) is a statistical technique widely used for the identification of coherent structures in turbulent flows [1][2][3], and, among other applications, has been applied to the analysis of turbulent thermal convection problems [4,5], study of jet pressure signals [6], modal identification of structures [7][8][9], and design-space dimensionality reduction in shape optimization problems [10,11]. POD has been used to study coherent structures in a transient buoyant jet in [12], whereas examples of application to planar jets are provided in [3,13]. Equivalent to the Karhunen-Loève expansion (KLE) and (in the discrete form) to the principal component analysis (PCA), POD allows to decompose the flow into a linear combination of a subset of orthogonal eigenfunctions, capable of highlighting its spatial/temporal structure and providing a reduced-order model (ROM) for the flow dynamics.…”

Section: Introductionmentioning

confidence: 99%

PIV Data Clustering of a Buoyant Jet in a Stratified Environment

Serani

Durante

Diez

et al. 2019

AIAA Scitech 2019 Forum

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Three spatial clustering approaches of a high-Reynolds number transient buoyant jet in a linearly stratified environment are applied along with proper orthogonal decomposition to identify similar/consistent regions in the domain of interest. The velocity fields analyzed are obtained from an experimental test with large scale, time-resolved, particle image velocimetry (PIV) measurements. Clustering is performed by the k-means method considering: (a) crosssection velocity profiles, (b) point-wise energy spectra, and (c) point-wise Reynolds stress tensor components. Three metrics are used for the assessment of clustering approaches, namely: (a) within-cluster sum of squares, (b) average silhouette, and (c) within-cluster number of POD modes required to resolve prescribed levels of total variance/energy. Results are promising and lay the foundation for an in depth analysis of local features of complex flows as well as the formulation of efficient reduced order models.

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Proper orthogonal decomposition analysis of the flow field in a plane jet

Cited by 43 publications

References 68 publications

Was the Deepwater Horizon Well Discharge Churn Flow? Implications on the Estimation of the Oil Discharge and Droplet Size Distribution

Was the Deepwater Horizon Well Discharge Churn Flow? Implications on the Estimation of the Oil Discharge and Droplet Size Distribution

Experimental study of the flow structures of 3D turbulent offset jets

PIV Data Clustering of a Buoyant Jet in a Stratified Environment

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