Many internal combust engine (ICE) models assume isotropic turbulence for at least a portion of the cycle \[1\].  While preliminary analysis with two-dimensional data has revealed that the turbulence becomes more isotropic as the piston approaches TDC, the validity of this assumption has not been fully investigated. This is partially due to lack of three-component velocity data in internal combustion engines, which precludes an in-depth assessment of the applicability range of the turbulence isotropy assumption due to the three-dimensional nature of turbulence. In this work, the velocity was measured using two-dimensional, three-component (2D-3C) particle image velocimetry in a single-cylinder, motored, research engine to investigate the development and evolution of turbulence anisotropy through the compression stroke with knowledge of the out-of-plane velocity component. The Lumley triangle was used as the metric to quantify the anisotropy throughout the compression stroke. The results provided insight into the anisotropy of the core-flow region and quantitative data to test the validity of common modeling assumptions.

\[1\] P. Miles, M. Megerle, Z. Nagel, R. Reitz, M.-C. D. Lai, and V. Sick, “An experimental assessment of turbulence production, Reynolds stress and length scale (dissipation) modeling in a swirl-supported DI Diesel Engine,” *SAE 2003 World Congr.*, 2003.


Turbulence Anisotropy Investigations in an Internal Combustion Engine

Division / Sponsors: 
Internal Combustion Engine Division (ICED)

Paper Proceedings: https://asmedigitalcollection.asme.org/ICEF/ICEF2020/volume/84034

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