Thermal Image Velocimetry

Inagaki, Atsushi; Kanda, Manabu; Onomura, Shiho; Kumemura, Hideaki

doi:10.1007/s10546-013-9832-z

Cited by 35 publications

(41 citation statements)

References 27 publications

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“…Given the small values of latent heat flux, for the remainder of the analysis, the latent heat flux is neglected. Note that, despite this assumption being poor in areas with significant vegetation, it would apply for other arid surfaces such as concrete or asphalt pavement as well as building walls in urban canopies (Inagaki et al , 2013).…”

Section: Seb‐tir Flux Measurement Methodssupporting

confidence: 81%

“…Other developments in thermo‐fluid dynamics show that thermal imagery has the potential to advance scientific understanding of turbulent flow phenomena (Hetsroni et al , 2001; Kowalewski et al , 2003; Christen et al , 2012; Garai et al , 2013; Inagaki et al , 2013). TIR has been utilised to capture transitions to turbulence (Peake et al , 1977), measure ground temperature fluctuations, advection velocities, and coherent turbulent structures (Hetsroni et al , 2001; Kowalewski et al , 2003; Christen and Voogt, 2010; Christen et al , 2012; Inagaki et al , 2013). Hence, TIR technology is becoming a mature measuring technique, with the appealing characteristic of providing two‐dimensional, plane measurements at a high temporal resolution.…”

Section: Introductionmentioning

confidence: 99%

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A methodology for computing spatially and temporally varying surface sensible heat flux from thermal imagery

Morrison

Calaf

Fernando

et al. 2017

Quart J Royal Meteoro Soc

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Thermal infrared imagery provides a measure of surface temperature by quantifying the thermal emission of radiation from objects. In this work, we propose a novel approach for computing surface sensible heat fluxes from a time series of thermal imagery sampled at 20 Hz. The approach consists of using a surface energy budget, where the ground heat flux is easily computed from limited measurements using a force–restore‐type methodology, the latent heat fluxes are neglected, and the energy storage is computed using a lumped capacitance model. Preliminary validation of the method is presented using experimental data acquired at a desert playa in western Utah from an intensive observation period during the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program. The sensible heat fluxes computed from thermal imagery show encouraging agreement (≈4% difference for 1 h averaged fluxes computed with the force–restore method) compared to heat fluxes obtained using the eddy‐covariance technique, however additional evaluation is required to confirm the method's validity. Further, the technique illustrates the richness of surface heat flux spatio‐temporal structure even over very smooth surfaces.

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Section: Seb‐tir Flux Measurement Methodssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

A methodology for computing spatially and temporally varying surface sensible heat flux from thermal imagery

Morrison

Calaf

Fernando

et al. 2017

Quart J Royal Meteoro Soc

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“…(b) Field measurement techniques to assess buoyancy driven flows in the urban environment have gradually improved from tethered balloons to the use of infrared camera for estimating surface temperatures [14] and wind velocities [73].…”

Section: Discussionmentioning

confidence: 99%

A Review of Some Recent Studies on Buoyancy Driven Flows in an Urban Environment

Hajra

2014

International Journal of Atmospheric Sciences

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This paper reviews some recent studies (after 2000) pertaining to buoyancy driven flows in nature and thier use in reducing air pollution levels in a city (city ventilation). Natural convection flows occur due to the heating and cooling of various urban surfaces (e.g., mountain slopes), leading to upslope and downslope flows. Such flows can have a significant effect on city ventilation which has been the subject of study in the recent times due to increased pollution levels in a city. A major portion of the research reviewed here consists of natural convection flows occurring along mountain slopes, with a few studies devoted to flows along building walls. The studies discussed here primarily include field measurements and computational fluid dynamics (CFD) models. This review shows that for densely populated cities with high pollution levels, natural convection flows (mountain slope or building walls) can significantly aid the dispersion of pollutants. Additional studies in this area using CFD and water channel measurements can explain the physical processes involved in such flows and help improve CFD modelling. Future research should focus on a complete understanding of the mechanisms of buoyancy flows in nature and developing design guidelines for better planning of cities.

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“…Turbulent wind flow across surfaces induces thermal fluctuations that move with the wind and that can appear similar to flowing gas. These turbulence-induced thermal fluctuations are a phenomenon that has only recently come to attention 8,9 as a method for imaging wind and which create patterns that are visible in trace gas imaging data. Infrared gas imaging and infrared wind imaging both use passive detection in primarily outdoor environments, relying on the same thermal contrast ΔT between the fluid and the background to produce signals.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity limits on optical gas imaging due to air turbulence

Hagen

2018

Opt. Eng.

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Infrared cameras are widely used for the detection of fugitive gas leaks and for quantifying gas emissions. While the gas detection sensitivity in the presence of noise is now well understood, we show that windturbulence-induced thermal fluctuations place a fundamental lower limit on gas detection sensitivity. While for many gases the lower limit is too low to be important, we show that for some gases it places a real limitation on measurements when the background is a near-ground surface.

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Thermal Image Velocimetry

Cited by 35 publications

References 27 publications

A methodology for computing spatially and temporally varying surface sensible heat flux from thermal imagery

A methodology for computing spatially and temporally varying surface sensible heat flux from thermal imagery

A Review of Some Recent Studies on Buoyancy Driven Flows in an Urban Environment

Sensitivity limits on optical gas imaging due to air turbulence

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