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	Author	García Sánchez, C.; Van Tendeloo, G.; Gorle, C.
	Title	Quantifying inflow uncertainties in RANS simulations of urban pollutant dispersion			Type	A1 Journal article
	Year	2017	Publication	Atmospheric environment : an international journal	Abbreviated Journal	Atmos Environ
	Volume	161	Issue		Pages	263-273
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Numerical simulations of flow and pollutant dispersion in urban environments have the potential to support design and policy decisions that could reduce the population's exposure to air pollution. Reynolds-averaged Navier-Stokes simulations are a common modeling technique for urban flow and dispersion, but several sources of uncertainty in the simulations can affect the accuracy of the results. The present study proposes a method to quantify the uncertainty related to variability in the inflow boundary conditions. The method is applied to predict flow and pollutant dispersion in downtown Oklahoma City and the results are compared to field measurements available from the Joint Urban 2003 measurement campaign. Three uncertain parameters that define the inflow profiles for velocity, turbulence kinetic energy and turbulence dissipation are defined: the velocity magnitude and direction, and the terrain roughness length. The uncertain parameter space is defined based on the available measurement data, and a non-intrusive propagation approach that employs 729 simulations is used to quantify the uncertainty in the simulation output. A variance based sensitivity analysis is performed to identify the most influential uncertain parameters, and it is shown that the predicted tracer concentrations are influenced by all three uncertain variables. Subsequently, we specify different probability distributions for the uncertain inflow variables based on the available measurement data and calculate the corresponding means and 95% confidence intervals for comparison with the field measurements at 35 locations in downtown Oklahoma City. (C) 2017 Elsevier Ltd. All rights reserved.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Oxford	Editor
	Language		Wos	000403515900025	Publication Date	2017-04-19
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1352-2310	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	3.629	Times cited	17	Open Access	OpenAccess
	Notes	; The first author's contribution to this work was supported by the doctoral (PhD) grant number 131423 for strategic basic research from the Agency for Innovation by Science and Technology in Flanders (IWT). This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number CTS160009 (Towns et al., 2014). ;			Approved	Most recent IF: 3.629
	Call Number	UA @ lucian @ c:irua:145761			Serial	4749
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	Author	Ercolani, G.; Gorle, C.; Garcia Sánchez, C.; Corbari, C.; Mancini, M.
	Title	RAMS and WRF sensitivity to grid spacing in large-eddy simulations of the dry convective boundary layer			Type	A1 Journal article
	Year	2015	Publication	Computers and fluids	Abbreviated Journal	Comput Fluids
	Volume	123	Issue	123	Pages	54-71
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Large-eddy simulations (LESS) are frequently used to model the planetary boundary layer, and the choice of the grid cell size, numerical schemes and sub grid model can significantly influence the simulation results. In the present paper the impact of grid spacing on LES of an idealized atmospheric convective boundary layer (CBL), for which the statistics and flow structures are well understood, is assessed for two mesoscale models: the Regional Atmospheric Modeling System (RAMS) and the Weather Research and Forecasting model (WRF). Nine simulations are performed on a fixed computational domain (6 x 6 x 2 km), combining three different horizontal (120, 60, 30 m) and vertical (20, 10, 5 m) spacings. The impact of the cell size on the CBL is investigated by comparing turbulence statistics and velocity spectra. The results demonstrate that both WRF and RAMS can perform LES of the CBL under consideration without requiring extremely high computational loads, but they also indicate the importance of adopting a computational grid that is adequate for the numerical schemes and subgrid models used. In both RAMS and WRF a horizontal cell size of 30 m is required to obtain a suitable turbulence reproduction throughout the CBL height. Considering the vertical grid spacing, WRF produced similar results for all the three tested values, while in RAMS it should be ensured that the aspect ratio of the cells does not exceed a value of 3. The two models were found to behave differently in function of the grid resolution, and they have different shortcomings in their prediction of CBL turbulence. WRF exhibits enhanced damping at the smallest scales, while RAMS is prone to the appearance of spurious fluctuations in the flow when the grid aspect ratio is too high. (C) 2015 Elsevier Ltd. All rights reserved.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Oxford	Editor
	Language		Wos	000365367500006	Publication Date	2015-10-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0045-7930	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.313	Times cited	3	Open Access
	Notes				Approved	Most recent IF: 2.313; 2015 IF: 1.619
	Call Number	UA @ lucian @ c:irua:130200			Serial	4236
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	Author	Gorle, C.; Garcia Sánchez, C.; Iaccarino, G.
	Title	Quantifying inflow and RANS turbulence model form uncertainties for wind engineering flows			Type	A1 Journal article
	Year	2015	Publication	Journal of wind engineering and industrial aerodynamics T2 – 6th International Symposium on Computational Wind Engineering (CWE), JUN 08-12, 2014, Hamburg, GERMANY	Abbreviated Journal	J Wind Eng Ind Aerod
	Volume	144	Issue	144	Pages	202-212
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT)
	Abstract	Reynolds-averaged Navier-Stokes (RANS) simulations are often used in the wind engineering practice for the analysis of turbulent bluff body flows. An approach that allows identifying the uncertainty related to the use of reduced-order turbulence models in RANS simulations would significantly increase the confidence in the use of simulation results as a basis for design decisions. In the present study we apply a strategy that enables quantifying these uncertainties by introducing perturbations in the Reynolds stress tensor to simulations of the flow in downtown Oklahoma City. The method is combined with a framework to quantify uncertainties in the inflow wind direction and intensity, and the final result of the UQ approach is compared to field measurement data for the velocity at 13 locations in the downtown area. (C) 2015 Elsevier Ltd. All rights reserved.
	Address
	Corporate Author				Thesis
	Publisher	Elsevier science bv	Place of Publication	Amsterdam	Editor
	Language		Wos	000360874900023	Publication Date	2015-08-18
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0167-6105	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	2.049	Times cited	22	Open Access
	Notes				Approved	Most recent IF: 2.049; 2015 IF: 1.414
	Call Number	UA @ lucian @ c:irua:127843			Serial	4230
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