A stochastic Lagrangian micromixing model for the dispersion of reactive scalars in turbulent flows: role of concentration fluctuations and improvements to the conserved scalar theory under non-homogeneous conditions

Pollutant fluxes in two-dimensional street canyons

“…For both the AR values, σ /c * ≈ 0 at the corner of the windward building, in agreement with the LES by Liu et al (2004). Worth noting also is that c /c * and σ /c * have the same order of magnitude, highlighting the importance of considering the standard deviation in quantitative concentration assessments conducted by means of appropriate numerical dispersion models, such as those based on the Lagrangian approach (Amicarelli et al, 2012;Amicarelli et al, 2017;Cassiani et al, 2013;Leuzzi et al, 2012;Marro et al, 2015).…”

Atmospheric Pollutant Dispersion over Complex Terrain: Challenges and Needs for Improving Air Quality Measurements and Modeling

“…First [224] and second order [225][226][227][228][229][230] chemical reactions can be solved in Lagrangian models, but only a limited number of chemical equations can be taken into account. It is generally recognized that the segregation of the chemical reactants cannot be neglected in short-term concentration predictions [231] when chemical reactions take place before the pollutants are well mixed by the turbulence.…”

Smoothed Particle Hydrodynamics Modeling with Advanced Boundary Conditions for Two-Dimensional Dam-Break Floods

“…In addition, should a "weakly compressible" approach be adopted, the non-iterative SPH algorithms are simplified [8].The limits of SPH models are linked to slightly higher computational costs, complex procedures for the local refining of spatial resolution, and a relatively low accuracy for classical CFD applications where mesh-based models are well-validated (e.g., confined mono-phase flows [8]). However, they are effectively employed in several fields [9][10][11][12][13][14][15][16][17][18].Various flood propagation studies have focused on the use of the SPH method to investigate dam-break events [19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Having implemented an SPH scheme to treat a dam-break problem in a two-phase approach, Colagrossi and Landrini [19] discussed the effects of density-ratio variations and air entrapment on loads.…”

“…The limits of SPH models are linked to slightly higher computational costs, complex procedures for the local refining of spatial resolution, and a relatively low accuracy for classical CFD applications where mesh-based models are well-validated (e.g., confined mono-phase flows [8]). However, they are effectively employed in several fields [9][10][11][12][13][14][15][16][17][18].…”