Abstract
Turbulence modulation in particle-laden stationary homogeneous isotropic turbulence is investigated using one-dimensional turbulence (ODT), a low-dimensional stochastic flow simulation model. For this purpose, ODT is extended in two ways. First, a forcing scheme that maintains statistical stationarity is introduced. Unlike direct numerical simulation (DNS) of forced turbulence, the ODT framework accommodates forcing that is not directly coupled to the momentum equation. For given forcing the ODT energy dissipation rate is therefore the same in particle-laden cases as in the corresponding single-phase reference case. Second, previously implemented one-way-coupled particle phenomenology is extended to two-way coupling using the general ODT methodology for flow modulation through interaction with any specified energy and momentum sources and sinks. As in a DNS comparison case for Re-lambda = 70, turbulence modulation is diagnosed primarily on the basis of the fluid-phase kinetic-energy spectrum. Because ODT involves subprocesses with straightforward physical interpretations, the ODT mechanisms of particle-induced turbulence modulation are clearly identified and they are plausibly relevant to particleladen Navier-Stokes turbulence. ODT results for the ratio of particle-phase and fluid-phase kinetic energies as a function of particle Stokes number and mass loading are reported for the purpose of testing these predictions in the future when these quantities are evaluated experimentally or using DNS.
Highlights
The interaction between particles or droplets and a turbulent flow are ubiquitous in nature and in industrial applications
The effect of the particle phase on the carrier phase turbulence is of longstanding interest and well known under the topic of turbulence modulation by particles
It is of main interest to understand its physical mechanisms and to develop a reliable subgrid-scale (SGS) model for large-eddy simulations (LESs)
Summary
The interaction between particles or droplets and a turbulent flow are ubiquitous in nature and in industrial applications. Rep is low and according to [2,6] this should result overall in an attenuation of TKE, but referring to a recent study of Mallouppas et al [7] this reasoning is not conclusive as they see an overall augmentation of TKE in the same flow configuration This shows how sensitive turbulence modulation is towards not just physical parameters and numerical frameworks. Boivin et al [12] developed a subgrid-scale (SGS) model for large eddy simulations (LES) based on their study [2] of forced, stationary HIT and could show that the model was able to capture the complex spectral behavior with high-Stokes number particles.
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