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A new vegetative barrier can help to reduce dust concentration in a surface coal mine neighbourhood. The project reports about quantification of this effect. An air flow field is computed together with the dust transport driven by it using an in-house CFD solver. The 2D cuts of a real geometry of Bílina coal mine in north Bohemia are used. The vegetation is modelled as horizontally homogeneous porous medium which slows the air flow inside. An influence on turbulence and filtering the dust particles...
The objective of this work is to obtain theoretical estimates on the large and small scales for geophysical flows. Firstly, we consider the shallow water problem in the one-dimensional case, then in the two-dimensional case. Finally we consider geophysical flows under the hydrostatic hypothesis and the Boussinesq approximation. Scale separation is based on Fourier series, with N models in each spatial direction, and the choice of a cut-off level N1 < N to define large and small scales. We...
Fast singular oscillating limits of
the three-dimensional "primitive" equations of
geophysical fluid flows are analyzed.
We prove existence on infinite time intervals
of regular solutions to the
3D "primitive" Navier-Stokes equations for strong
stratification (large stratification parameter N).
This uniform existence is proven for
periodic or stress-free boundary conditions
for all domain aspect ratios,
including the case of three wave resonances
which yield nonlinear " dimensional"
limit equations...
Durations of rain events and drought events over a given region provide important information about the water resources of the region. Of particular interest is the shape of upper tails of the probability distributions of such durations. Recent research suggests that the underlying probability distributions of such durations have heavy tails of hyperbolic type, across a wide range of spatial scales from 2 km to 120 km. These findings are based on radar measurements of spatially averaged rain rate...
Atmospheric flow equations govern the time evolution of chemical concentrations in the
atmosphere. When considering gas and particle phases, the underlying partial differential
equations involve advection and diffusion operators, coagulation effects, and evaporation
and condensation phenomena between the aerosol particles and the gas phase. Operator
splitting techniques are generally used in global air quality models. When considering
organic aerosol...
The first part of this paper reviews the single time scale/multiple length scale low Mach number asymptotic analysis by Klein (1995, 2004). This theory explicitly reveals the interaction of small scale, quasi-incompressible variable density flows with long wave linear acoustic modes through baroclinic vorticity generation and asymptotic accumulation of large scale energy fluxes. The theory is motivated by examples from thermoacoustics and combustion. In an almost obvious way specializations of this...
The first part of this paper reviews the single time scale/multiple
length scale low Mach number asymptotic analysis by Klein (1995, 2004).
This theory explicitly reveals the interaction of small scale,
quasi-incompressible variable density flows with long wave linear
acoustic modes through baroclinic vorticity generation and asymptotic
accumulation of large scale energy fluxes. The theory is motivated by
examples from thermoacoustics and combustion. In an almost obvious way specializations of...
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