The effect of the Reynolds number on the velocity and temperature distributions of a turbulent condensing jet

Cha, Jinho; Lim, Seungho; Kim, Taejoon; Shin, Weon Gyu

doi:10.1016/j.ijheatfluidflow.2017.08.001

Cited by 10 publications

(8 citation statements)

References 23 publications

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“…Unlike in porous channel (single-phase flow) studies, Figure 8(b) shows that the velocity profile decreases with an increase in Re p . The reason is that the velocity distribution decreases to satisfy the conservation of pore momentum as Re p increases because of the condensation process (Figure 1(b)) that occurs at a low Re p number, consistent with [102]. In addition, in agreement with [102], Figure 8(b) shows that the velocity decay rate is slower at high Re p than at low Re p .…”

Section: Journal Of Applied Mathematicssupporting

confidence: 60%

A Novel Multivariate Spectral Local Quasilinearization Method (MV-SLQLM) for Modelling Flow, Moisture, Heat, and Solute Transport in Soil

Mwakilama

Magagula

Gathungu

2023

Journal of Applied Mathematics

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Conventionally, the problem of studying the transport of water, heat, and solute in soil or groundwater systems has been numerically solved using finite difference (FD) or finite element (FE) methods. FE methods are attractive over FD methods because they are geometrically flexible. However, recent studies demonstrate that spectral collocation (SC) methods converge exponentially faster than FD or FE methods using a few grid points or on coarse grids. This work proposes and applies a multivariate spectral local quasilinearization method (MV-SLQLM) to model the transportation and interaction of soil moisture, heat, and solute concentration in a nonbare soil ridge. The MV-SLQLM uses a quasilinearization method (QLM) to linearize any nonlinear equations and then employs a local linearization method (LLM) to decouple the linearized system of PDEs to form a sequence of equations that are solved in a computationally efficient manner. The MV-SLQLM is thus an extension of the bivariate spectral local linearization method (BI-SLLM) that fails to deal with a 2D problem and is a modification of the MV-SQLM whose efficiency is compromised when operating on high dense solution matrices. We use the residual error norms of the difference between successive iterations to affirm convergence to the expected solution. To illustrate the application and check the solution accuracy, we conduct systematic analyses of the effect of model parameters on distribution profiles. Findings are in good agreement with theory and literature, thereby revealing suitability of the MV-SLQLM to solve coupled nonlinear PDEs with environmental fluid dynamics applications.

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Section: Journal Of Applied Mathematicssupporting

confidence: 60%

A Novel Multivariate Spectral Local Quasilinearization Method (MV-SLQLM) for Modelling Flow, Moisture, Heat, and Solute Transport in Soil

Mwakilama

Magagula

Gathungu

2023

Journal of Applied Mathematics

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“…However, it is not possible to appreciate the effectivity of the model itself owing to the following reasons:The model played a secondary role and the algorithms were enriched with wind velocity data.Their experiments were performed without paying attention to the validity of the model in these singular circumstances, specifically ignoring the distribution of velocities generated by their gas sources and the reduced dimensions of the rooms. For the case of Ishida et al, the concentration distribution in the immediate vicinity of their source is conical, approaching the turbulent jet theory [25] more than the Gaussian plume. For the case of Marques et al, they use two sources, which can provoke overlapping effects.Possible inaccuracies in the concentration when ignoring the effects of temperature and humidity on the gas sensors, in both cases metal-oxide sensors.…”

Section: Introductionmentioning

confidence: 89%

“…Their experiments were performed without paying attention to the validity of the model in these singular circumstances, specifically ignoring the distribution of velocities generated by their gas sources and the reduced dimensions of the rooms. For the case of Ishida et al, the concentration distribution in the immediate vicinity of their source is conical, approaching the turbulent jet theory [25] more than the Gaussian plume. For the case of Marques et al, they use two sources, which can provoke overlapping effects.…”

Section: Introductionmentioning

confidence: 89%

“…Taylor [28] deduces the form of σ by distinguishing two dispersion behaviors that are dependent on the correlation between the initial and final state of movement of the particles that constitute the pollutant. When the correlation is high, the plume presents a conical behavior as generated by a nozzle [25] with σ proportional to time t. If the correlation is low, then the plume can approximate the Gaussian model with σ∝t1/2.…”

Section: Theoretical Gas Distributionmentioning

confidence: 99%

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An Application of the Gaussian Plume Model to Localization of an Indoor Gas Source with a Mobile Robot

Sánchez-Sosa

Castillo-Mixcóatl

Beltrán-Pérez

et al. 2018

Sensors

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The source localization of gas leaks is important to avoid any potential danger to the surroundings or the probable waste of resources. Currently there are several localization methods using robotic systems that try to find the origin of a gas plume. Many of these methods require wind velocity information involving the use of commercial anemometric systems which are extremely expensive compared to metal oxide gas sensors. This article proposes the validation of the Gaussian plume model inside an empty room and its application to localize the source of a gas plume without employing anemometric sensors, exclusively using concentration data. The model was selected due to its simplicity and since it easily admits variants closer to reality, explaining the behavior of pollutants transported by the wind. An artificial gas source was generated by a conventional fan and liquid ethanol as contaminant. We found that the physical fan, far from making the model impossible to implement, enriched the information and added realism. The use of a robotic system capable of autonomously mapping the room concentration distribution is described. The results showed that the Gaussian plume model is applicable to localize our experimental gas source. An estimated position of the source with a deviation of 14 cm (6.1%) was obtained.

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“…Turbulent jets have been widely studied analytically, computationally, and experimentally for several decades in a wide range of fields, including water conservation and hydropower engineering, aerospace engineering, water supply and drainage engineering and environmental engineering [1][2][3][4][5][6][7][8][9]. In combination with environmental water conservation projects, turbulent jets play an important role in the discharge of effluents into water systems, including rivers, streams, lakes, seas and water in the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Effect of a Lateral Jet on the Turbulent Flow Characteristics of an Open Channel Flow with Rigid Vegetation

Sufen

Feng

Chen

et al. 2018

Water

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Aquatic vegetation can purify polluted bodies of water and beautify the environment, as well as alter the structure of water flow and affect the migration and diffusion of pollutants in bodies of water. Vegetation can significantly change the original water flow, especially in cases in which aquatic vegetation interacts with a jet. Characteristics of jet flow open channels without vegetation have been studied, but research on the characteristics of open-channel flows under the action of lateral jets and in the presence of vegetation are rare. High-frequency particle image velocimetry (PIV) was used to measure a lateral jet in water with rigid vegetation and our results were compared to the lateral jet flow field in water without vegetation. The results show that the vegetation arrangement and vegetation resistance cause significant changes. The presence of vegetation increased the surface velocity of the water, and the flow velocity decreased in the interior area of the vegetation and near the bottom of the water tank. The changes in flow velocity with changes in water depth displayed “S” type and anti-“S” type distributions, and the flow velocity of free layer was approximately logarithmic. Due to vegetation resistance and jet pressure differences, the lateral jet trajectory in water with vegetation was more likely to bend than in water without vegetation. The turbulence intensity and Reynolds stress had different distributions for water with and without vegetation. At the top of the vegetation and near the water surface, turbulent mixing of the water flow was strong, the flow velocity gradient was large and the turbulence intensity and the Reynolds stress reached their maxima. The effects of a lateral jet on an open-channel flow were compared for different vegetation conditions, revealing that a rhombic vegetation arrangement has a stronger deceleration effect than other arrangements. The theoretical results can be applied to wastewater discharge into vegetation channels.

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The effect of the Reynolds number on the velocity and temperature distributions of a turbulent condensing jet

Cited by 10 publications

References 23 publications

A Novel Multivariate Spectral Local Quasilinearization Method (MV-SLQLM) for Modelling Flow, Moisture, Heat, and Solute Transport in Soil

A Novel Multivariate Spectral Local Quasilinearization Method (MV-SLQLM) for Modelling Flow, Moisture, Heat, and Solute Transport in Soil

An Application of the Gaussian Plume Model to Localization of an Indoor Gas Source with a Mobile Robot

Effect of a Lateral Jet on the Turbulent Flow Characteristics of an Open Channel Flow with Rigid Vegetation

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