Mesoscale modeling characteristics

For the present discussion, we do not need to know the exact form of the mesoscale model for the fluid velocity and characteristic properties (e.g. composition and enthalpy). Instead, we will simply assume that and obey ... 

Above, we gave one example of the relationship between our dimensionless simulation parameters and physical dimensional values. The characteristic time scales given in the first paragraph in this section can be rescaled for different values of the diffusion coefficient and for different length scales in the system. (Namely, the distance between two lattice sites, could be chosen to be a different value one should, however, keep in mind that the model is a mesoscale model.)... 

We wished to develop a macroscopic model of the interactions between molecular ligands and receptors. Molecular recognition is a broad subject that describes selective assembly in chemistry and biology, with examples from DNA-protein complex formation to asymmetric catalysis. The principle behind molecular recognition dictates that the molecules that mate have complementary shapes and interfacial characteristics. Our extension of this principle to the mesoscale involved the self-assembly of objects that matched both... 

The static stability of the air stream usually changes as it moves into and out of the urban area, typically becoming less and more stable, respectively. However it should not be assumed that the boundary layer profiles over the urban area and downwind are identical to the equilibrium states found in neutral, stable and unstable boundary layers over flat terrain. In fact as the flow adjusts characteristic distortions of the air flow profiles occur on these scales, such as blocked flow, unsteady slope flows, gravity currents and boundary layer jets especially near hills, coasts and urban/rural boundaries. These distorted profiles (which are ignored in most mesoscale atmospheric models) significantly affect dispersion (e.g. Hogstrom and Smedman, [274] Owinoh et al., [477]). 

The SM2-U model (Dupont and Mestayer, 2004 [158] Dupont et al., 2005 [160]) is based on the force-restore model of Noilhan and Planton 1989 [469] for the transfers between the atmosphere, one vegetation layer, and three soil layers in its most recent version, ISBA-3L (Boone et al., 1999 [66]). It keeps the principal characteristics of this soil model and was developed as a pre-processor for fine resolution sub-mesoscale simulations. The surface dynamic influence is represented through roughness lengths... 

Particle-based simulation techniques include atomistic MD and coarse-grained molecular dynamics (CG-MD). Accelerated dynamics methods, such as hyperdynamics and replica exchange molecular dynamics (REMD), are very promising for circumventing the timescale problem characteristic of atomistic simulations. Structure and dynamics at the mesoscale level can be described within the framework of coarse-grained particle-based models using such methods as stochastic dynamics (SD), dissipative particle dynamics (DPD), smoothed-particle hydrodynamics (SPH), lattice molecular dynamics (LMD), lattice Boltzmann method (IBM), multiparticle collision dynamics (MPCD), and event-driven molecular dynamics (EDMD), also referred to as collision-driven molecular dynamics or discrete molecular dynamics (DMD). 

In a gas—sohd CFB with heterogeneous reactions and mass transfer, in Hne with the structural characteristics of the SFM model (Hong et al, 2012), as shown in Fig. 12, the mass transfer and reaction in any local space can be divided into components of the dense cluster (denoted by subscript c), the dilute broth (denoted by subscript f), and in-between (denoted by subscript i), respectively. And these terms can be represented by Ri (1 = gc, gf, gi, sc, sf, si). Both the dense and dilute phases are assumed homogenous and continuous inside, and the dense phase is fiarther assumed suspended uniformly in the dilute phase in forms of clusters of particles. Then the mass transfer terms can be described with Ranz-Marshall-hke relations for uniform suspension of particles (Haider and Basu, 1988). In particular, the mesoscale interaction over the cluster will be treated as is for a big particle with hydrodynamic equivalent diameter of d. Due to dynamic nature of clusters, there are mass exchanges between the dilute and dense phases with rate ofTk (k = g, s), pointing outward from the dilute to the dense phase. 

The model on the submicroscale is developed to calculate the coUision of single particles considering the influence of the Hquid layers on their surfaces by solving of the force balance, which includes the capillary and viscous forces. As a result from this model, the particle sticking criterion is estimated. Due to a combination of this criterion with characteristics obtained from microscale and mesoscales, the agglomeration rate in the apparatus can be predicted. 

---