3D MRI measurements of the effects of wind direction on flow characteristics and contaminant dispersion in a model urban canopy

Shim, Gawoon; Prasad, Dipak; Elkins, Christopher J.; Eaton, John K.; Benson, Michael J.

doi:10.1007/s10652-019-09676-y

Cited by 10 publications

(21 citation statements)

References 29 publications

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“…Besides, MRI velocimetry has been used in a variety of flow situations, such as the evolution of the composition of a drying sessile droplet (Kind and Thiele 2019), flow in a 3D meandering channel (Wiese et al 2018), turbulent inclined jet in crossflow (Milani et al 2019), concentration distribution during injection in another liquid (Banko et al 2020), flow in a model urban canopy (Shim et al 2019), Taylor-Couette instability (Seymour et al 1999). Remarkably, for the Taylor-Couette change of stability in a coaxial cylinder geometry with a superimposed axial flow, a complete view of the internal characteristics could be obtained (Vallatos et al 2012).…”

Section: Complex Fluid Flowsmentioning

confidence: 99%

Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Coussot

2020

Exp Fluids

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We review the uses of nuclear magnetic resonance techniques for experiments with fluids. More precisely we focus on the progress of knowledge in complex flows, rheology of complex fluids, flow in porous media, colloid transport, fluid transfers in complex porous systems, which have been allowed by NMR techniques. These achievements took advantage of the versatility of NMR, which makes it possible to carry out more original measurements than the basic well-known density imaging (MRI). One may thus rely on non-destructive, non-invasive, local velocimetry, local rheometry, statistical approaches of molecular displacements or velocity, distribution of adsorbed or suspended colloids, evolution of the liquid distribution in different states, fluid transfers during drying or imbibition, etc.

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Section: Complex Fluid Flowsmentioning

confidence: 99%

Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Coussot

2020

Exp Fluids

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“…The organization of this work is as follows: the second section briefly describes the ABLE-LBM, its boundary conditions, and the turbulent parameterization used in this study. The third section presents results of the ABLE-LBM simulations of turbulent flows around the buildings and compares the model results with laboratory results of Shim et al [29]. The fourth and final section gives a summary of the work and draws conclusions.…”

Section: Introductionmentioning

confidence: 91%

“…There are several data sets of laboratory turbulent flows over a variety of building arrays [25][26][27][28], in which different techniques such as hot wire, particle imaging velocimetry, and laser Doppler anemometry were used for velocity measurements. We focus mainly on the Shim et al [29] data set which used the magnetic resonance imaging technique known as MRV (Magnetic Resonance Velocimetry), for the model validation study. The MRI technique is a non-invasive and non-optical technique [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

“…We focus mainly on the Shim et al [29] data set which used the magnetic resonance imaging technique known as MRV (Magnetic Resonance Velocimetry), for the model validation study. The MRI technique is a non-invasive and non-optical technique [29][30][31]. It provides highly detailed three-dimensional time averaged measurements of the three-component velocity fields throughout the building array domains.…”

Section: Introductionmentioning

confidence: 99%

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Large-eddy simulation of turbulent flows over an urban building array with the ABLE-LBM and comparison with 3D MRI observed data sets

Wang

Benson

2020

Environ Fluid Mech

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In this article we describe the details of an ABLE-LBM (Atmospheric Boundary Layer Environment-Lattice Boltzmann Model) validation study for urban building array turbulent flow simulations. The ABLE-LBM large-eddy simulation results were compared with a set of 3D magnetic resonance image (MRI) velocimetry data. The ABLE-LBM simulations used the same building layout and Reynolds numbers operated in the laboratory water channel. The building set-up was an evenly spaced orthogonal array of cubic buildings (height = H) with a central tall building (height = 3H) in the second row. Two building orientations, angled with 0°and 45° wind directions, were simulated with ABLE-LBM. The model produced horizontal and vertical fields of time-averaged velocity fields and compared well with the experimental results. The model also produced urban canyon flows and vortices at front and lee sides and over building tops that were similar in strength and location to the laboratory studies. The turbulent kinetic energy associated with these two wind directions were also presented in this simulation study. It is shown that the building array arrangement, especially the tall building, has a great effect on turbulent wind fields. There is a Karman vortex street on the lee side of the tall building. High turbulent intensity areas are associated with the vortex shedding motions at building edges. In addition, the wind direction is a very important factor for turbulent wind and kinetic energy distribution. This validation study indicated that ABLE-LBM is a viable simulation model for turbulent atmospheric boundary layer flows in the urban building array. The computational speed of ABLE-LBM using the GPU has shown that real-time LES simulation is realizable for a computational domain with several millions grid points.

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“…The older wind-tunnel investigations primarily used point observations, either using hot-wire or laser Doppler anemometers (e.g., Snyder and Lawson 1994;Baik et al 2000;Kastner-Klein and Rotach 2004;Kastner-Klein et al 2004). More recently, the new techniques such as particle image velocimetry (PIV), Irwin probes, and magnetic resonance velocimetry have been used for the laboratory measurement of turbulent flow fields (e.g., Addepalli and Pardyjak 2013;Kuo et al 2015;Shim et al 2019). The advantage of these new techniques is that they can measure turbulence fields at different spatial points simultaneously, which gives a holistic picture of the flow field and can be more easily compared to the numerical models (Nemati Hayati et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulations of Turbulent Flows around Buildings Using the Atmospheric Boundary Layer Environment–Lattice Boltzmann Model (ABLE-LBM)

Wang

Decker

Pardyjak

2020

Journal of Applied Meteorology and Climatology

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A three-dimensional, prognostic Atmospheric Boundary Layer Environment-Lattice Boltzmann Model (ABLE-LBM) using the multiple-relaxation-time lattice Boltzmann method was developed for large-eddy simulation of urban boundary layer atmospheric flows. In this article we describe the details of the ABLE-LBM for urban flow, its implementation of complex boundaries, and the subgrid turbulence parameterizations. As a first validation of this newly developed model, the simulation results were evaluated with two wind-tunnel datasets that were collected using particle image velocimetry and Irwin probes, respectively. The ABLE-LBM simulations use the same building layout and Reynolds numbers used in the laboratory wind tunnels. The ABLE-LBM simulations compare favorably to both laboratory studies in terms of the mean wind fields. The turbulent fluxes simulated by the model in the observational planes also agreed reasonably well with the laboratory results. The model produced urban canyon flows and vortices on the lee side and over the building tops that are similar to those of the laboratory studies in strength and location. This validation study using laboratory data indicates that our new ABLE-LBM is a viable approach for modeling atmospheric turbulent flows in urban environments. A numerical implementation using a graphics processing unit shows that real-time simulations are achieved for these two validation cases.

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3D MRI measurements of the effects of wind direction on flow characteristics and contaminant dispersion in a model urban canopy

Cited by 10 publications

References 29 publications

Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Progress in rheology and hydrodynamics allowed by NMR or MRI techniques

Large-eddy simulation of turbulent flows over an urban building array with the ABLE-LBM and comparison with 3D MRI observed data sets

Large-Eddy Simulations of Turbulent Flows around Buildings Using the Atmospheric Boundary Layer Environment–Lattice Boltzmann Model (ABLE-LBM)

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