Momentum transfer in a turbulent, particle-laden Couette flow
نویسندگان
چکیده
A point-force model is used to study turbulent momentum transfer in the presence of moderate mass loadings of small (relative to Kolmogorov scales), dense (relative to the carrier phase density) particles. Turbulent Couette flow is simulated via direct numerical simulation, while individual particles are tracked as Lagrangian elements interacting with the carrier phase through a momentum coupling force. This force is computed based on the bulk drag of each particle, computed from its local slip velocity. By inspecting a parameter space consisting of particle Stokes number and mass loading, a general picture of how and under what conditions particles can alter near-wall turbulent flow is developed. In general, it is found that particles which adhere to the requirements for the point-particle approximation attenuate small-scale turbulence levels, as measured by wall-normal and spanwise velocity fluctuations, and decrease turbulent fluxes. Particles tend to weaken near-wall vortical activity, which in turn, through changes in burst/sweep intensities, weakens the ability of the turbulent carrier-phase motion to transfer momentum in the wall-normal direction. Compensating this effect is the often-ignored capacity of the dispersed phase to carry stress, resulting in a total momentum transfer which remains nearly unchanged. The results of this study can be used to interpret physical processes above the ocean surface, where sea spray potentially plays an important role in vertical momentum transfer. C 2013 AIP Publishing LLC.
منابع مشابه
development of an explicit eulerian method for treating particle laden turbulent flow in dust collectors
متن کامل
Modification of near-wall coherent structures by inertial particles
Articles you may be interested in Large eddy simulations of Taylor-Couette-Poiseuille flows in a narrow-gap system A hybrid stochastic-deconvolution model for large-eddy simulation of particle-laden flow A unified probability density function formulation to model turbulence modification in two-phase flow Characterization of near-wall turbulence in terms of equilibrium and " bursting " solutions...
متن کاملTurbulence modification by inertial particles and its influence on the spectral energy budget in planar Couette flow
Articles you may be interested in Modification of near-wall coherent structures by inertial particles Two-way coupled, particle-laden simulations are performed in turbulent Couette flow with the purpose of investigating the spectral extent of the particle influence on the turbulent energy cascade in wall-bounded flows. Direct numerical simulation of the carrier phase is performed in conjunction...
متن کاملA multiscale model for dilute turbulent gas-particle flows based on the equilibration of energy concept
The objective of this study is to improve Eulerian-Eulerian models of particle-laden turbulent flow. We begin by understanding the behavior of two existing models—one proposed by Simonin von Kármán Institute of Fluid Dynamics Lecture Series, 1996 , and the other by Ahmadi Int. J. Multiphase Flow 16, 323 1990 —in the limiting case of statistically homogeneous particle-laden turbulent flow. The d...
متن کاملTowards Large Eddy Simulation of Non-Homogeneous Particle Laden Turbulent Gas Flows Using Euler-Euler Approach
A Large Eddy Simulation approach for Eulerian-Eulerian dispersed two-phase flow is presented. It is shown that not only a Sub-Grid Scales term modeling the unresolved field in the mesoscopic momentum transport equation of the dispersed phase, but also a stress term modeling the Random-Uncorrelated Motion is needed. Simulations of a non-homogeneous particle laden turbulent gas flow allow to comp...
متن کامل