TY - JOUR
T1 - Quality and reliability of LES of convective scalar transfer at high Reynolds numbers
AU - Li, Qi
AU - Bou-Zeid, Elie R.
AU - Anderson, William
AU - Grimmond, Sue
AU - Hultmark, Marcus Nils
N1 - Funding Information:
This study was funded by the US National Science Foundation’s Sustainability Research Network Cooperative Agreement # 1444758 and Water Sustainability and Climate program Grant # CBET-1058027. The simulations were performed on the supercomputing clusters of the National Center for Atmospheric Research through project P36861020. W.A. was supported by the Army Research Office Environmental Sciences Directorate (Grant # W911NF-15-1-0231; PM: Dr. J. Parker).
Publisher Copyright:
© 2016 Elsevier Ltd
PY - 2016/11/1
Y1 - 2016/11/1
N2 - Numerical studies were performed to assess the quality and reliability of wall-modeled large eddy simulation (LES) for studying convective heat and mass transfer over bluff bodies at high Reynolds numbers (Re), with a focus on built structures in the atmospheric boundary layer. Detailed comparisons were made with both wind-tunnel experiments and field observations. The LES was shown to correctly capture the spatial patterns of the transfer coefficients around two-dimensional roughness ribs (with a discrepancy of about 20%) and the average Nusselt number (Nu) over a single wall mounted cube (with a discrepancy of about 25%) relative to wind tunnel measurements. However, the discrepancy in Re between the wind tunnel measurements and the real-world applications that the code aims to address influence the comparisons since Nu is a function of Re. Evaluations against field observations are therefore done to overcome this challenge; they reveal that, for applications in urban areas, the wind-tunnel studies result in a much lower range for the exponent m in the classic Nu ∼ Rem relations, compared to field measurements and LES (0.52–0.74 versus ≈ 0.9). The results underline the importance of conducting experimental or numerical studies for convective scalar transfer problems at a Re commensurate with the flow of interest, and support the use of wall-modeled LES as a technique for this problem that can already capture important aspects of the physics, although further development and testing are needed.
AB - Numerical studies were performed to assess the quality and reliability of wall-modeled large eddy simulation (LES) for studying convective heat and mass transfer over bluff bodies at high Reynolds numbers (Re), with a focus on built structures in the atmospheric boundary layer. Detailed comparisons were made with both wind-tunnel experiments and field observations. The LES was shown to correctly capture the spatial patterns of the transfer coefficients around two-dimensional roughness ribs (with a discrepancy of about 20%) and the average Nusselt number (Nu) over a single wall mounted cube (with a discrepancy of about 25%) relative to wind tunnel measurements. However, the discrepancy in Re between the wind tunnel measurements and the real-world applications that the code aims to address influence the comparisons since Nu is a function of Re. Evaluations against field observations are therefore done to overcome this challenge; they reveal that, for applications in urban areas, the wind-tunnel studies result in a much lower range for the exponent m in the classic Nu ∼ Rem relations, compared to field measurements and LES (0.52–0.74 versus ≈ 0.9). The results underline the importance of conducting experimental or numerical studies for convective scalar transfer problems at a Re commensurate with the flow of interest, and support the use of wall-modeled LES as a technique for this problem that can already capture important aspects of the physics, although further development and testing are needed.
KW - Forced convective heat transfer
KW - Large-eddy simulation
KW - Rough walls
KW - Urban heat exchange
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U2 - 10.1016/j.ijheatmasstransfer.2016.06.093
DO - 10.1016/j.ijheatmasstransfer.2016.06.093
M3 - Article
AN - SCOPUS:84978286095
SN - 0017-9310
VL - 102
SP - 959
EP - 970
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
ER -