The drag-reducing phenomenon in forced homogeneous isotropic turbulence (FHIT) with polymer additives was realized in large eddy simulation (LES) results, which causes the variation of turbulent characteristics. Study on intermittency of turbulence is of great importance in investigating turbulent drag-reduction mechanism, because the intermittency has close relationship with coherent structures (CSs) and the transfer of energy in turbulent flows. In the present work, the influences of polymers on intermittency in FHIT were analyzed in detail by extracting CSs, researching the flatness factor based on high-order correlation function of velocity derivative and wavelet transform, surveying local intermittence measure, and discussing four rotational invariants consisting of velocity-strain tensor and vorticity tensor. From the viewpoint of the results, it can be perceived that the intermittency occurs in both the Newtonian fluid and polymer solution flows; moreover polymer additives behave inhibitive effect on the intermittency in turbulent drag-reducing flows.
- Fluids Engineering Division
Effects of Polymer Additives on Intermittency in Forced Homogeneous Isotropic Turbulence
Wang, L, Wang, Y, Cai, W, & Li, F. "Effects of Polymer Additives on Intermittency in Forced Homogeneous Isotropic Turbulence." Proceedings of the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 1D, Symposia: Transport Phenomena in Mixing; Turbulent Flows; Urban Fluid Mechanics; Fluid Dynamic Behavior of Complex Particles; Analysis of Elementary Processes in Dispersed Multiphase Flows; Multiphase Flow With Heat/Mass Transfer in Process Technology; Fluid Mechanics of Aircraft and Rocket Emissions and Their Environmental Impacts; High Performance CFD Computation; Performance of Multiphase Flow Systems; Wind Energy; Uncertainty Quantification in Flow Measurements and Simulations. Chicago, Illinois, USA. August 3–7, 2014. V01DT27A009. ASME. https://doi.org/10.1115/FEDSM2014-21328
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