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Air Flow Study around Isolated Cubical Building in the City of Athens under Various Climate Conditions. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12073410] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study focuses on the airflow and pollutant dispersion around an isolated cubical building located in a warm Mediterranean climate, taking into account the local microclimate conditions (of airflow, albedo of building and soil, and air humidity) using a large-eddy simulation (LES) numerical approach. To test the reliability of computations, comparisons are made against the SILSOE cube experimental data. Three different scenarios are examined: (a) Scenario A with adiabatic walls, (b) Scenario B with the same constant temperature on all the surfaces of the building, and (c) Scenario C using convective and radiative conditions imposed by the local microclimate. For the first two cases the velocity and temperature fields resulting are almost identical. In the third case, the resulting temperature on the surfaces of the building is increased by 19.5%, the center (eye) of the wake zone is raised from the ground and the maximum pollutant concentration is drastically reduced (89%).
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2
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On the Viability of Video Imaging in Leak Rate Quantification: A Theoretical Error Analysis. SENSORS 2021; 21:s21175683. [PMID: 34502574 PMCID: PMC8434307 DOI: 10.3390/s21175683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 11/25/2022]
Abstract
Optical gas imaging through multispectral cameras is a promising technique for mitigation of methane emissions through localization and quantification of emissions sources. While more advanced cameras developed in recent years have led to lower uncertainties in measuring gas concentrations, a systematic analysis of the uncertainties associated with leak rate estimation have been overlooked. We present a systematic categorization of the involved uncertainties with a focus on a theoretical analysis of projection uncertainties that are inherent to this technique. The projection uncertainties are then quantified using Large Eddy Simulation experiments of a point source release into the atmosphere. Our results show that while projection uncertainties are typically about 5% of the emission rate, low acquisition times and observation of the gas plume at small distances from the emission source (<10 m) can amount to errors of about 20%. Further, we found that acquisition times on the order of tens of seconds are sufficient to significantly reduce (>50%) the projection uncertainties. These findings suggest robust procedures on how to reduce projection uncertainties, however, a balance between other sources of uncertainty due to operational conditions and the employed instrumentation are required to outline more practical guidelines.
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Abstract
A high-resolution large eddy simulation (LES) of wind flow over the Oklahoma City downtown area was performed to explain the effect of the building height on wind flow over the city. Wind flow over cities is vital for pedestrian and traffic comfort as well as urban heat effects. The average southerly wind speed of eight meters per second was used in the inflow section. It was found that heights and distribution of the buildings have the greatest impact on the wind flow patterns. The complexity of the flow field mainly depended on the location of buildings relative to each other and their heights. A strong up and downflows in the wake of tall buildings as well as large-scale coherent eddies between the low-rise buildings were observed. It was found out that high-rise buildings had the highest impact on the urban wind patterns. Other characteristics of urban canopy flows, such as wind shadows and channeling effects, are also successfully captured by the LES. The LES solver was shown to be a powerful tool for understanding urban canopy flows; therefore, it can be used in similar studies (e.g., other cities, dispersion studies, etc.) in the future.
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Study of Realistic Urban Boundary Layer Turbulence with High-Resolution Large-Eddy Simulation. ATMOSPHERE 2020. [DOI: 10.3390/atmos11020201] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study examines the statistical predictability of local wind conditions in a real urban environment under realistic atmospheric boundary layer conditions by means of Large-Eddy Simulation (LES). The computational domain features a highly detailed description of a densely built coastal downtown area, which includes vegetation. A multi-scale nested LES modelling approach is utilized to achieve a setup where a fully developed boundary layer flow, which is also allowed to form and evolve very large-scale turbulent motions, becomes incident with the urban surface. Under these nonideal conditions, the local scale predictability and result sensitivity to central modelling choices are scrutinized via comparative techniques. Joint time–frequency analysis with wavelets is exploited to aid targeted filtering of the problematic large-scale motions, while concepts of information entropy and divergence are exploited to perform a deep probing comparison of local urban canopy turbulence signals. The study demonstrates the utility of wavelet analysis and information theory in urban turbulence research while emphasizing the importance of grid resolution when local scale predictability, particularly close to the pedestrian level, is sought. In densely built urban environments, the level of detail of vegetation drag modelling description is deemed most significant in the immediate vicinity of the trees.
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Schmid MF, Lawrence GA, Parlange MB, Giometto MG. Volume Averaging for Urban Canopies. BOUNDARY-LAYER METEOROLOGY 2019; 173:349-372. [PMID: 31708585 PMCID: PMC6822781 DOI: 10.1007/s10546-019-00470-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
When canopy flows are horizontally averaged to obtain mean profiles, the averaging operation can be defined either as an intrinsic average, normalized by the variable fluid volume, or as a superficial average, normalized by the total volume including solid canopy elements. Properties of spatial averages have been explored extensively in the context of flow through plant canopies, albeit with the assumption that the solid volume fraction is negligible. Without this simplification, properties relevant for non-linear terms apply to intrinsic averages while properties of gradients apply to superficial averages. To avoid inconsistencies and inaccuracies the impact of a non-negligible solid volume fraction should be considered carefully when interpreting mean profiles, when deriving mathematical relations for averaged quantities, and when introducing modelling assumptions for such terms. On this basis, we review the definitions and properties of the method of volume averaging, as developed in the more general context of flow through porous media, and discuss its application to urban canopy flows. We illustrate the properties of intrinsic and superficial averages and their effect on mean profiles with example data from a simulation of flow over constant-height cubes.
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Affiliation(s)
- Manuel F. Schmid
- Department of Civil Engineering, University of British Columbia, Vancouver, BC Canada
| | - Gregory A. Lawrence
- Department of Civil Engineering, University of British Columbia, Vancouver, BC Canada
| | - Marc B. Parlange
- Department of Civil Engineering, Monash University, Melbourne, VIC Australia
| | - Marco G. Giometto
- Department of Civil Engineering and Engineering Mechanics, Columbia University, New York, NY USA
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6
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Crossing Multiple Gray Zones in the Transition from Mesoscale to Microscale Simulation over Complex Terrain. ATMOSPHERE 2019. [DOI: 10.3390/atmos10050274] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This review paper explores the field of mesoscale to microscale modeling over complex terrain as it traverses multiple so-called gray zones. In an attempt to bridge the gap between previous large-scale and small-scale modeling efforts, atmospheric simulations are being run at an unprecedented range of resolutions. The gray zone is the range of grid resolutions where particular features are neither subgrid nor fully resolved, but rather are partially resolved. The definition of a gray zone depends strongly on the feature being represented and its relationship to the model resolution. This paper explores three gray zones relevant to simulations over complex terrain: turbulence, convection, and topography. Taken together, these may be referred to as the gray continuum. The focus is on horizontal grid resolutions from ∼10 km to ∼10 m. In each case, the challenges are presented together with recent progress in the literature. A common theme is to address cross-scale interaction and scale-awareness in parameterization schemes. How numerical models are designed to cross these gray zones is critical to complex terrain applications in numerical weather prediction, wind resource forecasting, and regional climate modeling, among others.
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A Numerical Study on the Development of Self-Similarity in a Wind Turbine Wake Using an Improved Pseudo-Spectral Large-Eddy Simulation Solver. ENERGIES 2019. [DOI: 10.3390/en12040643] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Large-eddy simulation (LES) is performed to investigate self-similarity in a wind turbine wake flow. The turbine is represented using an actuator line model in a pseudo-spectral method-based solver. A new hybrid approach of smoothed pseudo-spectral method and finite-difference method (sPSMFDM) is proposed to alleviate the Gibbs phenomenon caused by the jump of velocity and pressure around the turbine. The LES is validated with the mean velocity and turbulence statistics obtained from wind-tunnel measurement reported in the literature. Through an appropriate choice of characteristic scales of velocity and length, self-similarity is elucidated in the normalized mean velocity and Reynolds stress profiles at various distances. The development of self-similarity is categorized into three stages based on the variation in the characteristic scales and the spanwise distribution of normalized velocity deficit. The mechanisms responsible for the transition of self-similarity stages are analyzed in detail. The findings of the flow physics obtained in this study will be useful for the modeling and fast prediction of wind turbine wake flows.
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Impact of Subgrid-Scale Modeling in Actuator-Line Based Large-Eddy Simulation of Vertical-Axis Wind Turbine Wakes. ATMOSPHERE 2018. [DOI: 10.3390/atmos9070257] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Fitzgerald BW, Padding JT, van Santen R. Simple diffusion hopping model with convection. Phys Rev E 2017; 95:013307. [PMID: 28208361 DOI: 10.1103/physreve.95.013307] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Indexed: 11/07/2022]
Abstract
We present results from a new variant of a diffusion hopping model, the convective diffusive lattice model, to describe the behavior of a particulate flux around bluff obstacles. Particle interactions are constrained to an underlying square lattice where particles are subject to excluded volume conditions. In an extension to previous models, we impose a real continuous velocity field upon the lattice such that particles have an associated velocity vector. We use this velocity field to mediate the position update of the particles through the use of a convective update after which particles also undergo diffusion. We demonstrate the emergence of an expected wake behind a square obstacle which increases in size with increasing object size. For larger objects we observe the presence of recirculation zones marked by the presence of symmetric vortices in qualitative agreement with experiment and previous simulations.
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Affiliation(s)
- Barry W Fitzgerald
- Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.,Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB, Delft, The Netherlands
| | - Johan T Padding
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB, Delft, The Netherlands
| | - Rutger van Santen
- Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands
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11
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Tong Z, Yang B, Hopke PK, Zhang KM. Microenvironmental air quality impact of a commercial-scale biomass heating system. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 220:1112-1120. [PMID: 27876224 DOI: 10.1016/j.envpol.2016.11.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/07/2016] [Accepted: 11/08/2016] [Indexed: 06/06/2023]
Abstract
Initiatives to displace petroleum and climate change mitigation have driven a recent increase in space heating with biomass combustion. However, there is ample evidence that biomass combustion emits significant quantities of health damaging pollutants. We investigated the near-source micro-environmental air quality impact of a biomass-fueled combined heat and power system equipped with an electrostatic precipitator (ESP) in Syracuse, NY. Two rooftop sampling stations with PM2.5 and CO2 analyzers were established in such that one could capture the plume while the other one served as the background for comparison depending on the wind direction. Four sonic anemometers were deployed around the stack to quantify spatially and temporally resolved local wind patterns. Fuel-based emission factors were derived based on near-source measurement. The Comprehensive Turbulent Aerosol Dynamics and Gas Chemistry (CTAG) model was then applied to simulate the spatial variations of primary PM2.5 without ESP. Our analysis shows that the absence of ESP could lead to an almost 7 times increase in near-source primary PM2.5 concentrations with a maximum concentration above 100 μg m-3 at the building rooftop. The above-ground "hotspots" would pose potential health risks to building occupants since particles could penetrate indoors via infiltration, natural ventilation, and fresh air intakes on the rooftop of multiple buildings. Our results demonstrated the importance of emission control for biomass combustion systems in urban area, and the need to take above-ground pollutant "hotspots" into account when permitting distributed generation. The effects of ambient wind speed and stack temperature, the suitability of airport meteorological data on micro-environmental air quality were explored, and the implications on mitigating near-source air pollution were discussed.
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Affiliation(s)
- Zheming Tong
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, United States
| | - Bo Yang
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, United States
| | - Philip K Hopke
- Center for Air Resources Engineering and Science Clarkson University, NY, 13699, United States
| | - K Max Zhang
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, 14853, United States.
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Gera GS, Yewalkar SN, Nene S, Kulkarni BD, Kamble S. Kinetic Studies on an Algal Biofilm Reactor for Raw Sewage Water Treatment. Chem Eng Technol 2016. [DOI: 10.1002/ceat.201500447] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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13
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A Large-Eddy Simulation Study of Vertical Axis Wind Turbine Wakes in the Atmospheric Boundary Layer. ENERGIES 2016. [DOI: 10.3390/en9050366] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Lateb M, Meroney RN, Yataghene M, Fellouah H, Saleh F, Boufadel MC. On the use of numerical modelling for near-field pollutant dispersion in urban environments--A review. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2016; 208:271-283. [PMID: 26282585 DOI: 10.1016/j.envpol.2015.07.039] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 07/19/2015] [Accepted: 07/23/2015] [Indexed: 05/19/2023]
Abstract
This article deals with the state-of-the-art of experimental and numerical studies carried out regarding air pollutant dispersion in urban environments. Since the simulation of the dispersion field around buildings depends strongly on the correct simulation of the wind-flow structure, the studies performed during the past years on the wind-flow field around buildings are reviewed. This work also identifies errors that can produce poor results when numerically modelling wind flow and dispersion fields around buildings in urban environments. Finally, particular attention is paid to the practical guidelines developed by researchers to establish a common methodology for verification and validation of numerical simulations and/or to assist and support the users for a better implementation of the computational fluid dynamics (CFD) approach.
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Affiliation(s)
- M Lateb
- New Jersey Institute of Technology (NJIT), Center for Natural Resources Development and Protection, Newark, NJ 07102, United States.
| | - R N Meroney
- Colorado State University, Department of Civil and Environmental Engineering, Fort Collins, CO 80523, United States
| | - M Yataghene
- National Research Institute of Science and Technology for Environment and Agriculture, Refrigerating Process Engineering, UR GPAN, Antony 92761, France
| | - H Fellouah
- Université de Sherbrooke, Department of Mechanical Engineering, Sherbrooke, QC J1K 2R1, Canada
| | - F Saleh
- New Jersey Institute of Technology (NJIT), Center for Natural Resources Development and Protection, Newark, NJ 07102, United States
| | - M C Boufadel
- New Jersey Institute of Technology (NJIT), Center for Natural Resources Development and Protection, Newark, NJ 07102, United States
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Giometto MG, Christen A, Meneveau C, Fang J, Krafczyk M, Parlange MB. Spatial Characteristics of Roughness Sublayer Mean Flow and Turbulence Over a Realistic Urban Surface. BOUNDARY-LAYER METEOROLOGY 2016; 160:425-452. [PMID: 32355338 PMCID: PMC7175723 DOI: 10.1007/s10546-016-0157-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/31/2016] [Indexed: 05/22/2023]
Abstract
Single-point measurements from towers in cities cannot properly quantify the impact of all terms in the turbulent kinetic energy (TKE) budget and are often not representative of horizontally-averaged quantities over the entire urban domain. A series of large-eddy simulations (LES) is here performed to quantify the relevance of non-measurable terms, and to explore the spatial variability of the flow field over and within an urban geometry in the city of Basel, Switzerland. The domain has been chosen to be centered around a tower where single-point turbulence measurements at six heights are available. Buildings are represented through a discrete-forcing immersed boundary method and are based on detailed real geometries from a surveying dataset. The local model results at the tower location compare well against measurements under near-neutral stability conditions and for the two prevailing wind directions chosen for the analysis. This confirms that LES in conjunction with the immersed boundary condition is a valuable model to study turbulence and dispersion within a real urban roughness sublayer (RSL). The simulations confirm that mean velocity profiles in the RSL are characterized by an inflection point z γ located above the average building height z h . TKE in the RSL is primarily produced above z γ , and turbulence is transported down into the urban canopy layer. Pressure transport is found to be significant in the very-near-wall regions. Further, spatial variations of time-averaged variables and non-measurable dispersive terms are important in the RSL above a real urban surface and should therefore be considered in future urban canopy parametrization developments.
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Affiliation(s)
- M. G. Giometto
- School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - A. Christen
- Geography/Atmospheric Science Program, University of British Columbia, Vancouver, BC Canada
| | - C. Meneveau
- Mechanical Engineering, Johns Hopkins University, Baltimore, MD USA
| | - J. Fang
- School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - M. Krafczyk
- Institute for Computational Modeling in Civil Engineering, TU Braunschweig, Braunschweig, Germany
| | - M. B. Parlange
- Civil Engineering, Faculty of Applied Sciences, University of British Columbia, Vancouver, BC Canada
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Viré A, Xiang J, Pain CC. An immersed-shell method for modelling fluid-structure interactions. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0085. [PMID: 25583857 PMCID: PMC4290410 DOI: 10.1098/rsta.2014.0085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The paper presents a novel method for numerically modelling fluid-structure interactions. The method consists of solving the fluid-dynamics equations on an extended domain, where the computational mesh covers both fluid and solid structures. The fluid and solid velocities are relaxed to one another through a penalty force. The latter acts on a thin shell surrounding the solid structures. Additionally, the shell is represented on the extended domain by a non-zero shell-concentration field, which is obtained by conservatively mapping the shell mesh onto the extended mesh. The paper outlines the theory underpinning this novel method, referred to as the immersed-shell approach. It also shows how the coupling between a fluid- and a structural-dynamics solver is achieved. At this stage, results are shown for cases of fundamental interest.
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Affiliation(s)
- A Viré
- Wind Energy Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS Delft, The Netherlands
| | - J Xiang
- Applied Modelling and Computation Group, Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK
| | - C C Pain
- Applied Modelling and Computation Group, Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK
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Nakayama H, Leitl B, Harms F, Nagai H. Development of local-scale high-resolution atmospheric dispersion model using large-eddy simulation. Part 4: turbulent flows and plume dispersion in an actual urban area. J NUCL SCI TECHNOL 2014. [DOI: 10.1080/00223131.2014.885400] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Anderson W, Chamecki M. Numerical study of turbulent flow over complex aeolian dune fields: the White Sands National Monument. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:013005. [PMID: 24580318 DOI: 10.1103/physreve.89.013005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Indexed: 06/03/2023]
Abstract
The structure and dynamics of fully developed turbulent flows responding to aeolian dune fields are studied using large-eddy simulation with an immersed boundary method. An aspect of particular importance in these flows is the downwind migration of coherent motions associated with Kelvin-Helmholtz instabilities that originate at the dune crests. These instabilities are responsible for enhanced downward transport of high-momentum fluid via the so-called turbulent sweep mechanism. However, the presence of such structures and their role in determining the bulk characteristics of fully developed dune field sublayer aerodynamics have received relatively limited attention. Moreover, many existing studies address mostly symmetric or mildly asymmetric dune forms. The White Sands National Monument is a field of aeolian gypsum sand dunes located in the Tularosa Basin in southern New Mexico. Aeolian processes at the site result in a complex, anisotropic dune field. In the dune field sublayer, the flow statistics resemble a mixing layer: At approximately the dune crest height, vertical profiles of streamwise velocity exhibit an inflection and turbulent Reynolds stresses are maximum; below this, the streamwise and vertical velocity fluctuations are positively and negatively skewed, respectively. We evaluate the spatial structure of Kelvin-Helmholtz instabilities present in the dune field sublayer (shear length L(s) and vortex spacing Λ(x)) and show that Λ(x)=m(dune)L(s), where m(dune)≈7.2 in the different sections considered (for turbulent mixing layers, 7<m<10 [M. M. Rogers and R. D. Moser, Phys. Fluids A 6, 903 (1994)]).
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Affiliation(s)
- William Anderson
- Mechanical Engineering Department and Center for Astrophysics, Space Physics and Engineering Research, Baylor University, Waco, Texas 76798, USA
| | - Marcelo Chamecki
- Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
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A Numerical Study of the Effects of Wind Direction on Turbine Wakes and Power Losses in a Large Wind Farm. ENERGIES 2013. [DOI: 10.3390/en6105297] [Citation(s) in RCA: 200] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Richmond-Bryant J, Saganich C, Bukiewicz L, Kalin R. Associations of PM2.5 and black carbon concentrations with traffic, idling, background pollution, and meteorology during school dismissals. THE SCIENCE OF THE TOTAL ENVIRONMENT 2009; 407:3357-3364. [PMID: 19250655 DOI: 10.1016/j.scitotenv.2009.01.046] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 12/31/2008] [Accepted: 01/15/2009] [Indexed: 05/27/2023]
Abstract
An air quality study was performed outside a cluster of schools in the East Harlem neighborhood of New York City. PM(2.5) and black carbon concentrations were monitored using real-time equipment with a one-minute averaging interval. Monitoring was performed at 1:45-3:30 PM during school days over the period October 31-November 17, 2006. The designated time period was chosen to capture vehicle emissions during end-of-day dismissals from the schools. During the monitoring period, minute-by-minute volume counts of idling and passing school buses, diesel trucks, and automobiles were obtained. These data were transcribed into time series of number of diesel vehicles idling, number of gasoline automobiles idling, number of diesel vehicles passing, and number of automobiles passing along the block adjacent to the school cluster. Multivariate regression models of the log-transform of PM(2.5) and black carbon (BC) concentrations in the East Harlem street canyon were developed using the observation data and data from the New York State Department of Environmental Conservation on meteorology and background PM(2.5). Analysis of variance was used to test the contribution of each covariate to variability in the log-transformed concentrations as a means to judge the relative contribution of each covariate. The models demonstrated that variability in background PM(2.5) contributes 80.9% of the variability in log[PM(2.5)] and 81.5% of the variability in log[BC]. Local traffic sources were demonstrated to contribute 5.8% of the variability in log[BC] and only 0.43% of the variability in log[PM(2.5)]. Diesel idling and passing were both significant contributors to variability in log[BC], while diesel passing was a significant contributor to log[PM(2.5)]. Automobile idling and passing did not contribute significant levels of variability to either concentration. The remainder of variability in each model was explained by temperature, along-canyon wind, and cross-canyon wind, which were all significant in the models.
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Affiliation(s)
- J Richmond-Bryant
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, NC 27711, United States.
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Brixey LA, Heist DK, Richmond-Bryant J, Bowker GE, Perry SG, Wiener RW. The effect of a tall tower on flow and dispersion through a model urban neighborhood : Part 2. Pollutant dispersion. ACTA ACUST UNITED AC 2009; 11:2171-9. [DOI: 10.1039/b907137g] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Heist DK, Brixey LA, Richmond-Bryant J, Bowker GE, Perry SG, Wiener RW. The effect of a tall tower on flow and dispersion through a model urban neighborhood : Part 1. Flow characteristics. ACTA ACUST UNITED AC 2009; 11:2163-70. [DOI: 10.1039/b907135k] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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