Adapting engineering CFD software for simulation of flow above complex terrain and various surface covers

Numerical modelling of the turbulent atmospheric boundary layer is becoming more and more important in environmental protection due to its role in improving air quality, exploiting wind energy and climate-conscious urban planning. During the development of numerical models it is important that there is good quality measurement data available to adjust the model parameters and to check the model quantitatively. The measurement results produced by systematic wind tunnel experiments (performed with the goals of the model development in mind) would have a big role in improving the numerical models developed by us.

A significant (and perhaps the most exciting) part of the atmospheric physical and transport phenomena takes place in the planetary boundary layer, namely the bottom few kilometers thick layer of the atmosphere surrounding the Earth. Turbulent flow phenomena dominate this layer, which is very complex and computationally demanding to describe. The use of turbulence models can reduce the computational costs but this decreases the precision as well. The main goal of our investigations is the adaptation of turbulence models and the corresponding boundary conditions used in general purpose engineering simulation software for atmospheric flows, as these models were not created to describe the atmospheric boundary layer. They are only suitable for general engineering tasks. The model adaptation and increasing precision gives a versatile and effective tool to the environment protection experts, engineers and decision makers as well.

During our research we would like to improve primarily the description of effects of terrain and surface coverage on flows. Field measurements related to this topic have limited availability as the rapidly changing meteorological conditions and variable surface make the measurements and the separate investigation of the effects difficult. The ideal (and also idealized) measurement environment for us would be the wind tunnel, which makes it possible to separately investigate the factors influencing the phenomena taking place in the turbulent boundary layer.

Involved researchers and departments

Dr. Miklós Balogh | BME Faculty of Mechanical Engineering | Department of Fluid Mechanics
Dr. Márton Balczó | BME Faculty of Mechanical Engineering | Department of Fluid Mechanics

Recent publications of BME on the subject

Balogh, G. Kristóf. Fine scale simulation of turbulent flows in urban canopy layers. Időjárás, 114 (1-2), 135-148, 2010.

Balogh, A. Parente, C. Benocci. RANS simulation of ABL flow over complex terrains applying an enhanced k-ε model and wall function formulation: Implementation and comparison for FLUENT and OpenFOAM. Journal of Wind Engineering and Industrial Aerodinamics, 2012 (104-106):360-368, 2012.

Peralta, A. Parente, M. Balogh, C. Benocci. RANS simulation of the atmospheric boundary layer over complex terrain with a consistent k-epsilon model formulation. In The 6th International Symposium on Computational Wind Engineering (CWE2014), 236-237, 2014.

Balogh, A. Parente. Realistic boundary conditions for the simulation of atmospheric boundary layer flows using an improved k-ε model. Journal of Wind Engineering and Industrial Aerodinamics, 2015 (144), 183–190, 2015.

B. Hermann, M. Balogh. A hybrid approach for the numerical simulation of flows in urban environment. 17th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes. 9-12 May 2016, Budapest, Hungary