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Hybrid LES/RANS Simulations of the Exhaust Plume in the Vehicle Wake
The present project aims to simulate and analyze pollutant dispersion in the vehicle wake in order to evaluate the possibilities of detecting heavily polluting vehicles with roadside stationary gas analyzers. Turbulence and its modeling play a major role in these simulations.
As part of an ongoing research collaboration between EMPA, ETHZ and external partners, there is an effort to develop high-fidelity and cost-efficient simulation models for a detailed description of the exhaust plume in the vehicle wake. The movement of a vehicle in the surrounding air induces a complex three-dimensional, turbulent flow characterized by high Reynolds numbers. The surrounding air enters the void space behind the moving vehicle, causing a circular vortex. This vortex evolves into smaller eddies. Such a flow detachment with recirculation zones is typical for the wake flow zone next to moving vehicles.
Since there are still uncertainties regarding the remote emission sensing (RES) technologies, the simulations will provide a substantial understanding of the pollutant dispersion and the main impacting parameters and dependencies. For a known operating point, with corresponding experimental data available, the simulation results can be used for a comparison/validation.
As part of an ongoing research collaboration between EMPA, ETHZ and external partners, there is an effort to develop high-fidelity and cost-efficient simulation models for a detailed description of the exhaust plume in the vehicle wake. The movement of a vehicle in the surrounding air induces a complex three-dimensional, turbulent flow characterized by high Reynolds numbers. The surrounding air enters the void space behind the moving vehicle, causing a circular vortex. This vortex evolves into smaller eddies. Such a flow detachment with recirculation zones is typical for the wake flow zone next to moving vehicles.
Since there are still uncertainties regarding the remote emission sensing (RES) technologies, the simulations will provide a substantial understanding of the pollutant dispersion and the main impacting parameters and dependencies. For a known operating point, with corresponding experimental data available, the simulation results can be used for a comparison/validation.
So far, a CFD model of the airflow around a vehicle considering the species of the exhaust plume is set up. As a possible approach for this project, a hybrid LES/RANS model is already implemented and used in order to gain accuracy in the vehicle wake region by keeping the computational cost at a minimum. Building on this, the goal of this student project is to gradually extend the simulation setup/framework and run several parameter studies in order to find correlations with experimental data and give implications for RES. Therefore, suitable parameters (vehicle speed, ambient conditions, pollutant concentrations etc.) have to be selected.
The project will run in close collaboration with the supervisor and the partner lab.
So far, a CFD model of the airflow around a vehicle considering the species of the exhaust plume is set up. As a possible approach for this project, a hybrid LES/RANS model is already implemented and used in order to gain accuracy in the vehicle wake region by keeping the computational cost at a minimum. Building on this, the goal of this student project is to gradually extend the simulation setup/framework and run several parameter studies in order to find correlations with experimental data and give implications for RES. Therefore, suitable parameters (vehicle speed, ambient conditions, pollutant concentrations etc.) have to be selected.
The project will run in close collaboration with the supervisor and the partner lab.
Interested candidates please send an email with a recent transcript of records to jplogmann@ethz.ch
Interested candidates please send an email with a recent transcript of records to jplogmann@ethz.ch