1,721,310 research outputs found
CFD simulation of pollutant dispersion around buildings: comparison between RANS k-ε and LES approaches
No full textTurbulence modeling is a key issue in computational wind engineering, particularly in the prediction of pollutant dispersion in cities. To be directly applicable, turbulence models
need validation by comparison with experiments. This paper evaluates the performance of two different modeling approaches (RANS k-e and LES) for three test cases with varying complexity. For each case, wind tunnel experiments are used for validation. It is shown that the performance of the standard k-e model is very case-dependent and that it also depends on the turbulent Schmidt number, whose optimum value is a priori unknown. On the contrary, LES with the dynamic subgrid-scale model shows a good performance for all cases, without requiring any parameter input to solve the dispersion equation. For the test case of an actual urban environment, predicted concentration values with LES differ from experiments by less than a factor of 2, compared to less than a factor of 4 with the standard k-e model
Integration of Beddoes-Leishman aerodynamic model into double streamtube theory for vertical axis wind turbines simulation
No full textA numerical methodology for the prediction of aerodynamics of VAWT is proposed, coupling the Beddoes-Leishman (BL) model for the airfoil’s unsteady aerodynamic coefficients prediction with the Paraschivoiu Double Streamtube (DS) aerodynamic model for VAWT. The model couples the rotational dynamics of the wind turbine modeled by DS with the aerodynamic coefficients degradation due to the local flow unsteadiness on the blade modeled by BL. The results achieved were compared with a set of experimental data available in literature and with CFD simulation, showing the importance of the non-stationary BL model for the blade’s aerodynamic coefficients prediction. Furthermore the coupled DSBL model is able to provide key information about the non-stationary aerodynamic conditions experienced on the blade for design and optimization purposes
Urban physics
Full text linkUrban Physics is the multiscale and interdisciplinary research area dealing with physical processes in urban environments that influence our everyday health, comfort and productivity. It involves disciplines ranging from mesoscale meteorology to human thermophysiology. The introductory lecture addresses basic research on numerical modeling of microscale atmospheric boundary layer processes as well as practical applications such as outdoor air pollution, pedestrian wind comfort and the urban heat island effect
Urban physics
No full textUrban Physics is the multiscale and interdisciplinary research area dealing with physical processes in urban environments that influence our everyday health, comfort and productivity. It involves disciplines ranging from mesoscale meteorology to human thermophysiology. The introductory lecture addresses basic research on numerical modeling of microscale atmospheric boundary layer processes as well as practical applications such as outdoor air pollution, pedestrian wind comfort and the urban heat island effect
Proceedings of the 13th international conference on wind engineering (ICWE13), July 10-15, 2011, Amsterdam
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