0
Research Papers

Effects of Outlier Flow Field on the Characteristics of In-Cylinder Coherent Structures Identified by Proper Orthogonal Decomposition-Based Conditional Averaging and Quadruple Proper Orthogonal Decomposition

[+] Author and Article Information
Rui Gao

UM-SJTU Joint Institute,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 200240, China
e-mail: garrygao@sjtu.edu.cn

Li Shen

UM-SJTU Joint Institute,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 200240, China
e-mail: sam_shen_li@outlook.com

Kwee-Yan Teh

UM-SJTU Joint Institute,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 200240, China
e-mail: tehk@sjtu.edu.cn

Penghui Ge

UM-SJTU Joint Institute,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 200240, China
e-mail: penghuige@sjtu.edu.cn

Fengnian Zhao

UM-SJTU Joint Institute,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 200240, China
e-mail: iclover@sjtu.edu.cn

David L.S. Hung

UM-SJTU Joint Institute,
Shanghai Jiao Tong University,
800 Dongchuan Road,
Shanghai 200240, China
e-mail: dhung@sjtu.edu.cn

1Corresponding author.

Manuscript received March 12, 2019; final manuscript received March 24, 2019; published online April 15, 2019. Editor: Jerzy T. Sawicki.

J. Eng. Gas Turbines Power 141(8), 081012 (Apr 15, 2019) (9 pages) Paper No: GTP-19-1125; doi: 10.1115/1.4043307 History: Received March 12, 2019; Revised March 24, 2019

Proper orthogonal decomposition (POD) offers an approach to quantify cycle-to-cycle variation (CCV) of the flow field inside the internal combustion engine cylinder. POD decomposes instantaneous flow fields (also called snapshots) into a series of orthonormal flow patterns (called POD modes) and the corresponding mode coefficients. The POD modes are rank-ordered by decreasing kinetic energy content, and the low-order, high-energy modes are interpreted as constituting the large-scale coherent flow structure that varies from engine cycle to engine cycle. Various POD-based analysis techniques have thus been proposed to characterize engine flow field CCV using these low-order modes. The validity of such POD-based analyses rests, as a matter of course, on the reliability of the underlying POD results (modes and coefficients). Yet a POD mode can be disproportionately skewed by a single outlier snapshot within a large data set, and an algorithm exists to define and identify such outliers. In this paper, the effects of a candidate outlier snapshot on the results of POD-based conditional averaging and quadruple POD analyses are examined for two sets of crank angle-resolved flow fields on the midtumble plane of an optical engine cylinder recorded by high-speed particle image velocimetry (PIV). The results with and without the candidate outlier are compared and contrasted. In the case of POD-based conditional averaging, the presence of the outlier scrambles the composition of snapshot subsets that define large-scale flow pattern variations, and thus substantially alters the coherent flow structures that are identified; for quadruple POD, the shape of coherent structures and the number of modes to define them are not significantly affected by the outlier.

FIGURES IN THIS ARTICLE
<>
Copyright © 2019 by ASME
Your Session has timed out. Please sign back in to continue.

References

Fansler, T. D. , Drake, M. C. , and Böhm, B. , 2008, “ High-Speed Mie-Scattering Diagnostics for Spray-Guided Gasoline Engine Development,” Eighth International Symposium on Combustion Diagnostic, Baden-Baden, Germany, June 10–11, pp. 413–425
Borée, J. , and Miles, P. C. , 2014, “ In-Cylinder Flow,” Encyclopedia of Automotive Engineering, Wiley, Hoboken, NJ.
Soltau, J. P. , 1960, “ Cylinder Pressure Variations in Petrol Engines,” Proc. Inst. Mech. Eng.: Automob. Div., 14(1), pp. 99–117.
Lumley, J. L. , 1967, “ The Structure of Inhomogeneous Turbulent Flows,” Atmospheric Turbulence and Radio Wave Propagation, Nauka, Moscow, Russia, pp. 166–178.
Glauser, M. N. , and George, W. K. , 1987, “ Orthogonal Decomposition of the Axisymmetric Jet Mixing Layer Including Azimuthal Dependence,” Advances in Turbulence, Springer, Berlin, pp. 357–366.
Moin, P. , and Moser, R. , 1989, “ Characteristic-Eddy Decomposition of Turbulence in a Channel,” J. Fluid. Mech., 200(1), pp. 471–509. [CrossRef]
Manhart, M. , and Wengle, H. , 1993, “ A Spatiotemporal Decomposition of a Fully Inhomogeneous Turbulent Flow Field,” Theor. Comput. Fluid Dyn., 5(4–5), pp. 223–242. [CrossRef]
Rempfer, D. , and Fasel, H. , 1994, “ Evolution of Three-Dimensional Coherent Structures in a Flat-Plate Boundary Layer,” J. Fluid. Mech., 260(1), pp. 351–375. [CrossRef]
Abraham, P. S. , Yang, X. , Gupta, S. , Kuo, T. , Reuss, D. L. , and Sick, V. , 2015, “ Flow-Pattern Switching in a Motored Spark Ignition Engine,” Int. J. Engine Res., 16(3), pp. 323–339. [CrossRef]
Buhl, S. , Hartmann, F. , and Hasee, C. , 2015, “ Identification of Large-Scale Structure Fluctuations in IC Engines Using POD-Based Conditional Averaging,” Oil Gas Sci. Technol., 71(1), p. 1. [CrossRef]
Druault, P. , Delville, J. , and Bonnet, J. , 2005, “ Proper Orthogonal Decomposition of the Mixing Layer Flow Into Coherent Structures and Turbulent Gaussian Fluctuations,” C. R. Méc., 333(11), pp. 824–829. [CrossRef]
Roudnitzky, S. , Druault, P. , and Guibert, P. , 2006, “ Proper Orthogonal Decomposition of In-Cylinder Engine Flow Into Mean Component, Coherent Structures and Random Gaussian Fluctuations,” J. Turbul., 7(70), pp. 1–19.
Qin, W. , Xie, M. , Jia, M. , Wang, T. , and Liu, D. , 2014, “ Large Eddy Simulation and Proper Orthogonal Decomposition Analysis of Turbulent Flows in a Direct Injection Spark Ignition Engine: Cyclic Variation and Effect of Valve Lift,” Sci. China Technol. Sci., 57(3), pp. 489–504. [CrossRef]
Shen, L. , Teh, K. , Ge, P. , Wang, Y. , and Hung, D. L. S. , 2017, “ Detecting Outliers in Crank Angle Resolved Engine Flow Field Datasets for Proper Orthogonal Decomposition Analysis,” SAE Paper No. 2017-01-0612.
Berkooz, G. , Holmes, P. , and Lumley, J. , 1993, “ The Proper Orthogonal Decomposition in the Analysis of Turbulent Flows,” Annu. Rev. Fluid Mech., 25(1), pp. 539–575. [CrossRef]
Chen, H. , Reuss, D. , Hung, D. , and Sick, V. , 2013, “ A Practical Guide for Using Proper Orthogonal Decomposition in Engine Research,” Int. J. Engine Res., 14(4), pp. 307–319. [CrossRef]
Liu, K. , and Haworth, D. , 2011, “ Development and Assessment of POD for Analysis of Turbulent Flow in Piston Engines,” SAE Paper No. 2011-01-0830.
Zhuang, H. , and Hung, D. L. S. , 2016, “ Characterization of the Effect of Intake Air Swirl Motion on Time-Resolved in-Cylinder Flow Field Using Quadruple Proper Orthogonal Decomposition,” Energy Convers. Manage., 108, pp. 366–376. [CrossRef]
Zhuang, H. , Hung, D. L. S. , Yang, J. , and Tian, S. , 2016, “ Investigation of Swirl Ratio Impact on in-Cylinder Flow in an SIDI Optical Engine,” ASME J. Eng. Gas Turbines Power, 138(8), p. 081505. [CrossRef]
Wang, Y. , Hung, D. L. S. , and Zhuang, H. X. M. , 2016, “ Cycle-to-Cycle Analysis of Swirl Flow Fields Inside a Spark-Ignition Direct-Injection Engine Cylinder Using High-Speed Time-Resolved Particle Image Velocimetry,” SAE Paper No. 2016-01-0637.
Westerweel, J. , 1997, “ Fundamentals of Digital Particle Image Velocimetry,” Meas. Sci. Technol., 8, pp. 1379–1392. [CrossRef]
Westerweel, J. , 2008, “ On Velocity Gradients in PIV Interrogation,” Exp. Fluids, 44(5), pp. 831–842. [CrossRef]
Abraham, P. , Liu, K. , Haworth, D. , Reuss, D. , and Sick, V. , 2014, “ Evaluating Large-Eddy Simulation (LES) and High-Speed Particle Image Velocimetry (PIV) With Phase-Invariant Proper Orthogonal Decomposition (POD),” Oil Gas Sci. Technol., 69(1), pp. 41–59. [CrossRef]
Chen, H. , Reuss, D. , and Sick, V. , 2012, “ On the Use and Interpretation of Proper Orthogonal Decomposition of In-Cylinder Engine Flows,” Meas. Sci. Technol., 23(8), p. 085302. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Four subsets defined in POD-based conditional averaging following the approach of Buhl et al. [10]

Grahic Jump Location
Fig. 2

Relevance indices calculated successively for snapshot B, along with the mean value across the dataset obtained at −235 CAD aTDC

Grahic Jump Location
Fig. 3

POD result before removing the outlier in the intake dataset (−235 deg). From left to right: ensemble mean; shape of mode 1; shape of mode 2.

Grahic Jump Location
Fig. 4

Scatter plot showing the mode 1 KE and mode 1 residue RI for the intake dataset (−235 deg)

Grahic Jump Location
Fig. 5

POD result after removing the outlier in the intake dataset (−235 deg). From left to right: the fluctuation term of the outlier snapshot; shape of mode 1 after removing the outlier snapshot; shape of mode 2 after removing the outlier snapshot.

Grahic Jump Location
Fig. 6

Subset distribution and subset averages of the intake dataset (−235 deg)

Grahic Jump Location
Fig. 7

Subset distribution after removing snapshot A in the intake dataset (−235 deg)

Grahic Jump Location
Fig. 8

Subset distribution and subset averages after removing the outlier snapshot from the intake dataset (−235 deg)

Grahic Jump Location
Fig. 9

Successive RI calculated for snapshots B and C, along with the mean value across the intake dataset (−235 deg) before and after the removal of the outlier

Grahic Jump Location
Fig. 10

Coherent flow patterns for snapshots B and C before and after removal of the outlier from the intake dataset (−235 deg), with threshold δ=0.95

Grahic Jump Location
Fig. 11

Coherent flow patterns for snapshots B and C before and after removal of the outlier from the intake dataset (−235 deg), with threshold δ=0.90

Tables

Errata

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In