Dissertation Thesis from Dr.-Ing. Cornelia Kalender-Wevers, 2015

Wind-induced particle transport - Synergetic combination of physical and numerical simulation.

Solid particles in our air, primary dusts and aerosols, can originate from anthropogenic and natural sources.
Their wind-induced transmission in the near-ground atmospheric boundary layer occurs over varying distances and concentrations to the immission area, depending on the size and density of the particles. Particularly respirable particles with diameters of 3 to 0.1 µm have a hazardous effect on human health. The Technical Instructions on Air Quality Control ("TA-Luft") therefore describe, among other things, measures to be implemented in construction engineering to contain and control emissions from dusty production or construction processes. To predict their effectiveness, detailed knowledge of the fluid mechanics of the entire transport chain to the point of immission is required.

For the prediction of wind-driven transmission, especially of the mentioned dust and aerosol fractions in the built environment, two different models are used in combination in this work. First, the modeling is done physically in a boundary layer wind tunnel using dispersion experiments with a tracer gas mixture, and second, numerically with a finite volume flow solver using an Euler and a trajectory model. A model is always a simplified representation of reality, so depending on the conception of the model, the model results will be different for the same application. The aim of this work is to combine the applied models with each other in such a way that their advantages are used hybridly and thus their respective model-specific disadvantages and limitations are overcome. This requires a detailed consideration of the different influencing parameters as well as the investigation of the respective uncertainties. It turned out that high-quality simulation results can only be achieved by careful preliminary investigations and independence tests. Thus, the synergetic use of both approaches allows to represent the transport of particles in the built environment as close to reality as possible and to gain new knowledge for the application in environmental engineering. As an application, this also and in particular concerns the effectiveness of partial enclosures, which are used for immission reduction during the handling and storage of dusty goods. It is shown that the respective model predictions complement each other and that their hybrid use increases the completeness of representation for the cases under investigation.