Turbulence modulation

For fluid velocities > 2.5 fps, and when lower volume fraction to be mixed is greater than 25% of total flow, use a dual turbulent module, i.e., AP, would be 2x for one module. 

Vermorel, O., et al.. Numerical study and modelling of turbulence modulation in a particle laden slab flow. /. Turbulence, 2003. 4(25) l-39. 

There are inherent phenomena associated with gas-solid flows. Such phenomena are of considerable interest to a wide spectrum of process applications involving gas-solid flows and can be exemplified by erosion, attrition, pressure-wave propagation, flow instability, and gas-solid turbulence modulation. 

One of the earliest models for turbulence modulation in homogeneous dilute particleladen flows is Hinze s model (1972), in which the assumption of vortex trapping of particles is employed. On the basis of this model, the particle turbulent kinetic energy, kp, is determined by the local gas turbulent kinetic energy k as... 

On the bais of an extensive review of experimental results of turbulence modulation in dilute suspension pipe flows and jet flows, Gore and Crowe (1989) proposed a critical ratio of particle diameter to a characteristic integral length scale of turbulence by the following relation... 

In general, at least six mechanisms, which are not independent of each other, contribute to turbulence modulation in gas-solid suspension flows ... 

Combined with Eq. (6.202), Eq. (6.203) yields the total turbulence modulation as... 

Yuan, Z. and Michaelides, E. E. (1992). Turbulence Modulation in Particulate Flows - a Theoretical Approach. Int. J. Multiphase Flow, 18,779. 

Crowe CT (2000) On models for turbulence modulation in fluid-particle flows. Int J Multiphase Flow 26 719-727... 

Parthasarathy, R.N., and Faeth, G.M. (1990a), Turbulence modulation in homogeneous dilute particle-laden flows, Journal of Fluid Mechanics, 220 485-514. 

Another aspect is the description of the turbulence in the gas phase due to the movement of the particles. Recent efforts aim to close the Euler—Euler models with appropriate closures for the turbulence and turbulence modulation, or describe the interaction among particles to form clusters which... 

The mere presence of dispersed phases within a continuous phase can also affect turbulence within the continuous phase [26], These effects are often named turbulence modulation. Large particles tend to increase the turbulence levels in the continuous phase, due to enhanced shear production in their wakes. However, large concentrations of small particles tend to decrease turbulence in the continuous phase. There is still no generally accepted model which is applicable to all flow conditions. 

Boivrn, M. Simonin,0. and Squires, K.D. Direct numerical simulation of turbulence modulation by particles in isotropic turbulence. I. Fluid Mech. 375.1998,235-263. 

Gualteri P, Picano F, Sardina G, Casciola CM Clustering and turbulence modulation in particle laden shear flows, J Fluid Mech 715 134—162, 2013. http //dx.doi.org/10.1017/jfin. 2012.503. 

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