Dispersion of Light and Heavy Pollutants in Urban Scale Models: CO₂ Laser Photoacoustic Studies

Abstract

The distribution of pollutants in two urban scale models (point emission source and street canyon with extensive transport) was investigated by means of CO(2) laser photoacoustic spectroscopy in the region of the atmospheric window (9-10 mum). The experimental results of physical modeling are in a good agreement with the numerical calculations performed in the frame of computational fluid dynamic (CFD) modeling. Methanol, ethanol, and ozone (examples of light pollutants), as well as sulfur hexafluoride and 1,2 dichlorethane (examples of heavy pollutants), were selected on the basis of their high resolution spectra acquired by Fourier transform and laser diode spectroscopy.

Physical Modeling of Gas Pollutant Motion in the Atmosphere

“…Profiles of the flow field physical characteristics were determined at the inlet of the geometry (see Table 2) based on experimental data from a low-speed wind tunnel for a 1:1000-scale model (see [3], [4], [5], [11]). For other model scales, the profiles were modified to keep the trend of curves.…”

“…ANSYS Fluent 13.0 CFD (Computational Fluid Dynamics) code was used to demonstrate and visualize all problem variants (see [1], [2]). The numerical model of the pollutant plume motion created in this software had been verified by an experiment conducted in the low-speed wind tunnel in the Aerodynamic Laboratory of the Academy of Sciences of the Czech Republic in Novy Knin (see [3], [4], [5]). One of the aims of the study is also to demonstrate that physical modeling of pollutant plume motion and dispersion with severely downscaled models has its limitations that should be known and considered to avoid obtaining false results.…”

Capacities and Limitations of Wind Tunnel Physical Experiments on Motion and Dispersion of Different Density Gas Pollutants

“…based on experimental data from a low-speed wind tunnel for a 1:1000-scale model (see [3], [4], [5], [6], [11]). For other model scales, the profiles were modified to keep the trend of curves.…”

“…ANSYS Fluent 15.0 CFD (Computational Fluid Dynamics) code was used to demonstrate and visualize all problem variants (see [1], [2]). The numerical model of the pollutant plume motion created in this software was verified by an experiment conducted in the low-speed wind tunnel in the Aerodynamic Laboratory of the Academy of Sciences of the Czech Republic in Novy Knin (see [3], [4], [5]). The maximum difference between experiment data and numerical simulation data sets was one order (for more details see [6]).…”

Silicon micro-levers and a multilayer graphene membrane studied via laser photoacoustic detection

“…In previous studies (to improve the physical modelling of urban air pollution), we have developed and employed laser photoacoustic spectrometry (Zelinger et al, 2004(Zelinger et al, , 2006(Zelinger et al, , 2009. The objective of this paper is to present the design and fabrication of several home-made sensing elements of the cantilever-and-membrane type and to test and characterize their mechanical properties with the aid of the developed PAS method.…”