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Journal articles on the topic 'Unsteady temperature fields'

Author: Grafiati

Published: 3 June 2025

Last updated: 20 July 2025

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1

Yariv, Ehud, and Howard Brenner. "Flow animation by unsteady temperature fields." Physics of Fluids 16, no. 11 (2004): L95—L98. http://dx.doi.org/10.1063/1.1801091.

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2

YARIV, EHUD. "Displacing small particles by unsteady temperature fields." Journal of Fluid Mechanics 530 (May 10, 2005): 125–34. http://dx.doi.org/10.1017/s0022112005003538.

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3

SHUAI, S., and J. WANG. "Unsteady temperature fields of monoliths in catalytic converters." Chemical Engineering Journal 100, no. 1-3 (2004): 95–107. http://dx.doi.org/10.1016/j.cej.2004.01.013.

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4

Biliaieva, V. V., and S. A. Shcherbyna. "Mathematical Modeling of Temperature Fields in Cultivation Structures." Science and Transport Progress, no. 4(108) (December 15, 2024): 13–20. https://doi.org/10.15802/stp2024/316334.

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Purpose. The main purpose of the article is to develop a method for calculating thermal fields in greenhouse soil in the case of its artificial heating. Since the temperature regime in greenhouse soil has a significant impact on plant yields, it is very important, on the one hand, to ensure the required temperature in the soil, and on the other hand, to determine the energy-saving heating regime. Methodology. The method is based on the numerical integration of the heat transfer equation. A two-dimensional heat transfer equation was used to analyze and predict the unsteady process of soil heating in a greenhouse under artificial heating, and two finite-difference schemes were used to solve it. On the basis of the constructed numerical models, a computer program was developed to conduct a computational experiment. Findings. Effective computer models have been created to predict the unsteady formation of thermal zones in the greenhouse soil during its artificial heating. The results of numerical modeling are presented. Originality. Prognostic numerical models have been developed to analyze the dynamics of thermal fields formation in greenhouse soil during its artificial heating. On the basis of the developed numerical models, a set of application programs was created to conduct a computational experiment to determine the unsteady temperature field in greenhouse soil. The constructed numerical models belong to the class of «operational models», i.e., they are designed for the operational analysis of thermal fields in the soil. For the practical use of the developed numerical models, standard input information is required. Practical value. The constructed numerical models are a tool for analyzing the dynamics of soil heating and can be used in the development of energy-saving heating technology. These models can be used to determine the time of optimal soil heating in different zones (root system, soil surface) and to determine the rational location of heating elements, the time when the heating elements should be turned off, and the time when they should be turned on again. These models allow us to develop an energy-saving technology for heating the soil in a greenhouse.

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5

Demchuk, O. N., and R. A. Starodub. "Determination of unsteady-state temperature fields in multilayered orthotopic plates." Journal of Engineering Physics and Thermophysics 63, no. 4 (1992): 1050–55. http://dx.doi.org/10.1007/bf00853358.

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6

Wei, Chenghao, Ryozo Ooka, Bingchao Zhang, and Qi Zhou. "Predicting Unsteady Indoor Temperature Distributions by POD-DNN." E3S Web of Conferences 356 (2022): 04028. http://dx.doi.org/10.1051/e3sconf/202235604028.

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In this study, to predict unsteady temperature distributions, POD-DNN was utilized, where DNN was trained to predicted coefficients of POMs. Two strategies, flatten POD-DNN and nested POD-DNN were compared. The flatten POD-DNN provided high accuracy if training data is sufficient, but otherwise very inaccurate. The nested POD-DNN roughly predicted the development of temperature fields even training data was small. The results showed their different sensitivities to the training data size.

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7

Zhang, Yan, Min Zhang, and Shujuan Qi. "Heat and Mass Transfer in a Thin Liquid Film over an Unsteady Stretching Surface in the Presence of Thermosolutal Capillarity and Variable Magnetic Field." Mathematical Problems in Engineering 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/8521580.

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The heat and mass transfer characteristics of a liquid film which contain thermosolutal capillarity and a variable magnetic field over an unsteady stretching sheet have been investigated. The governing equations for momentum, energy, and concentration are established and transformed to a set of coupled ordinary equations with the aid of similarity transformation. The analytical solutions are obtained using the double-parameter transformation perturbation expansion method. The effects of various relevant parameters such as unsteady parameter, Prandtl number, Schmidt number, thermocapillary number, and solutal capillary number on the velocity, temperature, and concentration fields are discussed and presented graphically. Results show that increasing values of thermocapillary number and solutal capillary number both lead to a decrease in the temperature and concentration fields. Furthermore, the influences of thermocapillary number on various fields are more remarkable in comparison to the solutal capillary number.

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8

Saastamoinen, J. J. "Unsteady state temperature fields in a slab induced by line sources." International Journal of Heat and Mass Transfer 50, no. 3-4 (2007): 756–65. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2006.07.001.

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9

Shyu, R. J., and C. K. Hsieh. "Unsteady Natural Convection in Enclosures With Stratified Medium." Journal of Solar Energy Engineering 109, no. 2 (1987): 127–33. http://dx.doi.org/10.1115/1.3268189.

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A numerical solution is given to study the unsteady natural convection in enclosures with stratified medium. Three designs of the enclosure wall are investigated that encompass a wall without insulation on it, insulation placed over the exterior of the wall, and insulation placed over the interior. The enclosed medium is initially stratified in the middle region and the wall temperature is uniform at the high temperature level of the medium. Computation results indicate the superiority of placing the insulation inside to maintain the thermal stratification in the medium. Flow and temperature fields are given for a quantitative substantiation of this observation.

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10

Ayub, Rashid, Shahzad Ahmad, Muhammad Imran Asjad, and Mushtaq Ahmad. "Heat Transfer Analysis for Viscous Fluid Flow with the Newtonian Heating and Effect of Magnetic Force in a Rotating Regime." Complexity 2021 (July 26, 2021): 1–11. http://dx.doi.org/10.1155/2021/9962732.

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In this article, an unsteady free convection flow of MHD viscous fluid over a vertical rotating plate with Newtonian heating and heat generation is analyzed. The dimensionless governing equations for temperature and velocity fields are solved using the Laplace transform technique. Analytical solutions are obtained for the temperature and components of velocity fields. The obtained solutions satisfy the initial and boundary conditions. Some physical aspects of flow parameters on the fluid motion are presented graphically.

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11

Tugolukov, E. N., A. V. Neprokin, A. V. Gorbunov, and V. M. Nechaev. "Method for Improving the Quality of Mathematical Modeling of Unsteady Temperature Fields." Vestnik Tambovskogo gosudarstvennogo tehnicheskogo universiteta 22, no. 4 (2016): 596–601. http://dx.doi.org/10.17277/vestnik.2016.04.pp.596-601.

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12

Mansour, M. A., and RSR Gorla. "Joule-heating effects on unsteady natural convection from a heatedvertical plate in a micropolar fluid." Canadian Journal of Physics 76, no. 12 (1998): 977–84. http://dx.doi.org/10.1139/p98-069.

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A boundary-layer solution is presented to study the effects of viscous and Joule heating on unsteady natural convection flow in a micropolar fluid. Viscous dissipation has been retained as a first-order term. Numerical results for the unsteady boundary-layer equations have been obtained at any point along the vertical plate using the finite-difference method. Details of the velocity, microrotation, and temperature fields are presented for various material parameters.PACS Nos.: 44.25+F, 47.27-i, and 47.27Te

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13

Pothanna, Nalimela, and P. Aparna. "The Unsteady Flow of a Fluid of Finite Depth with an Oscillating Bottom." International Frontier Science Letters 15 (February 2020): 1–8. http://dx.doi.org/10.18052/www.scipress.com/ifsl.15.1.

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In this paper, the unsteady flow of a fluid of finite depth with an oscillating bottom is examined. The flow is assumed in the absence of viscous dissipation. The governing equations of the flow are decoupled in the velocity and temperature fields. The velocity and temperature fields have been obtained analytically. The effects of various material parameters on these fields have been discussed with the help of graphical illustrations. It is noticed that the upward thrust (ρfy) vanishes when Reiner Rivlin coefficient of viscosity (μc) is zero and the transverse force (ρfz) perpendicular to the flow direction vanishes for thermo-viscosity coefficient (α8) is zero. The external forces generated perpendicular to the flow direction is a special feature of thermo-viscous fluid when compared to the other type of fluids.

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14

Kumar, M. Satish, Naramgari Sandeep, B. Rushi Kumar, and Salman Saleem. "Effect of Aligned Magnetic Field on MHD Squeezing Flow of Casson Fluid between Parallel Plates." Defect and Diffusion Forum 384 (May 2018): 1–11. http://dx.doi.org/10.4028/www.scientific.net/ddf.384.1.

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The two-dimensional unsteady magnetohydrodynamic squeezing flow and heat transfer of Casson fluid between two parallel plates with aligned magnetic field and nonlinear thermal radiation is investigated theoretically. The resulting governing equations are transformed as set of ODEs and solved numerically by using bvp4c Matlab package. The influence of various pertinent parameters on the flow and temperature fields are discussed with the assistance of graphical illustrations. The reduced Nusselt number are presented through graphs. It is seen that increasing values of squeeze number depreciate the flow and temperature fields.

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15

Mythreye, A., and J. P. Pramod. "Effects of Chemical Reaction on Unsteady MHD Free Convective Flows past a Vertical Porous Plate Embedded in a Porous Medium with Variable Suction." European Modern Studies Journal 7, no. 4 (2023): 315–25. http://dx.doi.org/10.59573/emsj.7(4).2023.29.

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In the present analysis we study two dimensional unsteady MHD free convection laminar heat and mass transfer flows past a vertical porous plate embedded in a porous medium with variable suction in the presence of chemical reaction and soret effects. Perturbation technique is applied to transform the non linear coupled governing partial differential equations in dimensionless form into a system of ordinary differential equations. The equations are solved analytically and the solutions for velocity, temperature and concentration fields are obtained. The effects of various parameters on velocity, temperature and concentration fields are presented graphically.

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16

Volkov, Roman S., Ivan S. Voytkov, and Pavel A. Strizhak. "Temperature Fields of the Droplets and Gases Mixture." Applied Sciences 10, no. 7 (2020): 2212. http://dx.doi.org/10.3390/app10072212.

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In this research, we obtain gas–vapor mixture temperature fields generated by blending droplets and high-temperature combustion products. Similar experiments are conducted for droplet injection into heated air flow. This kind of measurement is essential for high-temperature and high-speed processes in contact heat exchangers or in liquid treatment chambers, as well as in firefighting systems. Experiments are conducted using an optical system based on Laser-Induced Phosphorescence as well as two types of thermocouples with a similar measurement range but different response times (0.1–3 s) and accuracy (1–5 °C). In our experiments, we inject droplets into the heated air flow (first scheme) and into the flow of high-temperature combustion products (second scheme). We concentrate on the unsteady inhomogeneous temperature fields of the gas–vapor mixture produced by blending the above-mentioned flows and monitoring the lifetime of the relatively low gas temperature after droplets passes through the observation area. The scientific novelty of this research comes from the first ever comparison of the temperature measurements of a gas–vapor–droplet mixture obtained by contact and non-contact systems. The advantages and limitations of the contact and non-contact techniques are defined for the measurement of gas–vapor mixture temperature.

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17

Hayat, Tasawar, Muhammad Qasim, and Zaheer Abbas. "Radiation and Mass Transfer Effects on the Magnetohydrodynamic Unsteady Flow Induced by a Stretching Sheet." Zeitschrift für Naturforschung A 65, no. 3 (2010): 231–39. http://dx.doi.org/10.1515/zna-2010-0312.

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This investigation deals with the influence of radiation on magnetohydrodynamic (MHD) and mass transfer flow over a porous stretching sheet. Attention has been particularly focused to the unsteadiness. The arising problems of velocity, temperature, and concentration fields are solved by a powerful analytic approach, namely, the homotopy analysis method (HAM). Velocity, temperature, and concentration fields are sketched for various embedded parameters and interpreted. Computations of skin friction coefficients, local Nusselt number, and mass transfer are developed and examined.

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18

KATAMINE, Eiji, and Naoya OKADA. "Shape Design of Unsteady Forced Heat-convection Fields to Control Temperature Distribution History." Proceedings of Mechanical Engineering Congress, Japan 2017 (2017): J1210103. http://dx.doi.org/10.1299/jsmemecj.2017.j1210103.

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19

KATAMINE, Eiji, and Shinya IMAI. "Solution to shape identification of unsteady natural convection fields to control temperature distribution." Transactions of the JSME (in Japanese) 82, no. 833 (2016): 15–00578. http://dx.doi.org/10.1299/transjsme.15-00578.

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20

Ispolov, Yu G., and N. N. Shabrov. "Finite-element analysis of unsteady temperature fields in parts of gas turbine engines." Strength of Materials 21, no. 12 (1989): 1720–26. http://dx.doi.org/10.1007/bf01533417.

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21

Narahari, Marneni, Sowmya Tippa, and Rajashekhar Pendyala. "Unsteady Magnetohydrodynamic Free Convection Flow of a Radiative Fluid Past an Infinite Vertical Plate with Constant Heat and Mass Flux." Applied Mechanics and Materials 465-466 (December 2013): 149–54. http://dx.doi.org/10.4028/www.scientific.net/amm.465-466.149.

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Theoretical analysis of unsteady magnetohydrodynamic free convection flow of a viscous incompressible radiative fluid past an infinite vertical plate with constant heat and mass flux is presented. The dimensionless governing linear partial differential equations have been solved using the Laplace transform technique. The exact solutions for the velocity, temperature and concentration fields are derived. The effects of radiation, magnetic field and buoyancy ratio parameters on the velocity and temperature fields are discussed through graphs. It is found that the velocity increases with increasing radiation parameter whereas it decreases with increasing magnetic field parameter for buoyancy assisted flows.

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22

Levin, Lev, Mikhail Semin, Stanislav Maltsev, Roman Luzin, and Andrey Sukhanov. "Numerical Analysis of the Impact of Variable Borer Miner Operating Modes on the Microclimate in Potash Mine Working Areas." Computation 13, no. 4 (2025): 85. https://doi.org/10.3390/computation13040085.

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This paper addresses the numerical simulation of unsteady, non-isothermal ventilation in a dead-end mine working of a potash mine excavated using a borer miner. During its operations, airflow can become unsteady due to the variable operating modes of the borer miner, the switching on and off of its motor cooling fans, and the movement of a shuttle car transporting ore. While steady ventilation in a dead-end working with a borer miner has been previously studied, the specific features of air microclimate parameter distribution in more complex and realistic unsteady scenarios remain unexplored. Our experimental studies reveal that over time, air velocity and, particularly, air temperature experience significant fluctuations. In this study, we develop and parameterize a mathematical model and perform a series of numerical simulations of unsteady heat and mass transfer in a dead-end working. These simulations account for the switching on and off of the borer miner’s fans and the movement of the shuttle car. The numerical model is calibrated using data from our experiments conducted in a potash mine. The analysis of the first factor is carried out by examining two extreme scenarios under steady-state ventilation conditions, while the second factor is analyzed within a fully unsteady framework using a dynamic mesh approach in the ANSYS Fluent 2021 R2. The numerical results demonstrate that the borer miner’s operating mode notably impacts the velocity and temperature fields, with a twofold decrease in maximum velocity near the cabin after the shuttle car departed and a temperature difference of about 1–1.5 °C between extreme scenarios in the case of forcing ventilation. The unsteady simulations using the dynamic mesh approach revealed that temperature variations were primarily caused by the borer miner’s cooling system, while the moving shuttle car generated short-term aerodynamic oscillations.

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23

Gorbunov, A.D., and S.V. Uklеina. "Engineering method of calculation temperature fields and thermal stresses in the initial stage of radiation convection heating (cooling) body with variable heat transfer coefficient, and the temperature at environment." Problemele Energeticii Regionale 2(31) (August 15, 2016): 69–76. https://doi.org/10.5281/zenodo.1208208.

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Existing solutions of radiant and convective heating (cooling) body problems at the initial stage at unsteady heat transfer coefficients and temperatures are rather cumbersome. The purpose of this work is getting simpler dependencies. Decisions are based on the analysis of relations between the cause (heat flow) and the effect (surface temperature) in the initial period of heating. Two simple and effective engineering methods of calculation of unsteady temperature fields, and axial thermal stresses at the initial stage of heating (cooling) of body of canonical form for both convection and radiation heat transfer at variable ambient temperature and environmental factors have been developed. Some of the solutions are generic in nature, which allows significantly reducing the number of variables and thus using the graphical method of problem solving. The formulas for calculating the bulk and central temperature in the initial stage are provided; other researchers of nonlinear heat conduction problems did not usually do this. It has been found that the axial thermal stresses are determined entirely by the heat flow on the surface. The adequacy of the developed techniques is based on five cases of calculation of heating (cooling) plates under various conditions of its thermal loading. It is shown that the error in determining the surface temperature does not exceed 6%, and that the developed method can be used up to Fourier numbers Fo \(\leq\)0,4.

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24

Mubarra Abbass and Iram Naz. "Effect of Ternary Hybrid Nanoparticles on Brinkman Type Fluid Flow between Two Walls." Mathematical Sciences and Applications 3, no. 1 (2024): 19–59. http://dx.doi.org/10.52700/msa.v3i1.24.

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The research delves into the intricate study of the fractional model of unsteady and incompressible MHD Brinkman fluid between vertical plates. Various fractional derivatives, along with appropriate boundary conditions, such as Caputo, Caputo-Fabrizio, Antangna Baleanu, and Prabhakar are applied. The non-dimensional equations are skillfully tackled using the Laplace transform method. The resulting solution for energy and momentum is presented in a series form. The study also delves into the intriguing influence of memory parameters on the temperature and velocity field, visually representing the mathematical outcomes for temperature and velocity fields across different parameters. Furthermore, the study provides insightful comparisons between different fractional derivatives, shedding light on their respective impacts on the temperature and velocity fields.

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25

Sazal, Md Labib, and Dr Md Mahmud Alam. "PARTIALLY ANALYTICAL SOLUTION OF UNSTEADY IONIZED FLUID FLOW WITH INDUCED MAGNETIC FIELD." International Journal of Engineering Applied Sciences and Technology 09, no. 06 (2024): 01–04. https://doi.org/10.33564/ijeast.2024.v09i06.001.

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Analytical studies have been conducted on combined heat and mass transfer in unsteady ionized fluid flow passing through a vertically oscillating electrically non-conducting plate under an induced magnetic field. Through the application of similarity transformations to coupled ordinary differential equations, an analytical solution for velocity fields, induced magnetic fields, and temperature distribution is obtained. The resulting graphs illustrate variations in the obtained results with different parameter values, highlighting the effects of ionized fluid flow under the influence of the induced magnetic field.

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26

Formalev, V. F., S. A. Kolesnik, and B. A. Garibyan. "Heat Transfer with Absorption in Anisotropic Thermal Protection of High-Temperature Products." Herald of the Bauman Moscow State Technical University. Series Natural Sciences, no. 5 (86) (October 2019): 35–49. http://dx.doi.org/10.18698/1812-3368-2019-5-35-49.

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The purpose of the research was to study the non-stationary heat transfer in anisotropic thermal protection under the action of unsteady heat flows distributed along the body, when there are thermal energy sinks inside the body, the energy being proportional to temperature, due to endothermic physical and chemical transformations. Thermal protection is made of anisotropic material, such as phenol-formaldehyde fiberglass, asboplastics, carbon-carbon plastics, etc. A new analytical solution has been obtained for the problem of plate heating under the action of unsteady heat flows distributed along the body. Using this solution, we studied the temperature fields when the components and orientation angles of the main axes of the thermal conductivity tensors of anisotropic heat-shielding materials were changed. Findings of research show that with increasing time, the temperature field inside the plate is localized and does not extend further than the limiting isotherm.

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27

Wei, P. S., S. C. Wang, and M. S. Lin. "Transport Phenomena During Resistance Spot Welding." Journal of Heat Transfer 118, no. 3 (1996): 762–73. http://dx.doi.org/10.1115/1.2822697.

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Unsteady, axisymmetric transport of mass, momentum, energy, species, and magnetic field intensity with a mushy-zone phase change in workpieces and temperature, and magnetic fields in electrodes during resistance spot welding, are systematically investigated. Electromagnetic force, joule heat, heat generation at the electrode–workpiece interface and faying surface between workpieces, different properties between phases, and geometries of electrodes are taken into account. The computed results show consistencies with observed nugget growth, electrical current, and temperature fields. The effects of the face radius and cone angle of the electrode, parameters governing welding current, electrical contact resistance, magnetic Prandtl number, electrical conductivity ratio, and workpiece thickness on transport phenomena are clearly provided.

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28

Wei, P. S., and F. B. Yeh. "Factors Affecting Nugget Growth With Mushy-Zone Phase Change During Resistance Spot Welding." Journal of Heat Transfer 113, no. 3 (1991): 643–49. http://dx.doi.org/10.1115/1.2910613.

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An unsteady, axisymmetric model is first proposed to investigate extensively effects of the physical, thermal, and metallurgical properties and welding conditions on nugget growths with mushy-zone phase change during resistance spot welding. The electromagnetic force, joule heat and interfacial heat generation, and cooling effects of electrodes are taken into account. Fluid patterns, temperature fields, and solute distributions in the liquid, solid, and mushy zones are determined. Results show that the computed nugget growths and temperature fields are consistent with experimental data. Variations of properties strongly affect the nugget growth. The maximum velocity in the weld nugget is found to be small and around 5 mm/s.

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29

Umavathi, J. C., A. J. Chamkha, A. Mateen, and A. Al-Mudhaf. "Unsteady Oscillatory Flow and Heat Transfer in a Horizontal Composite Porous Medium Channel." Nonlinear Analysis: Modelling and Control 14, no. 3 (2009): 397–415. http://dx.doi.org/10.15388/na.2009.14.3.14503.

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The problem of unsteady oscillatory flow and heat transfer in a horizontal composite porous medium is performed. The flow is modeled using the Darcy-Brinkman equation. The viscous and Darcian dissipation terms are also included in the energy equation. The partial differential equations governing the flow and heat transfer are solved analytically using two-term harmonic and non-harmonic functions in both regions of the channel. Effect of the physical parameters such as the porous medium parameter, ratio of viscosity, oscillation amplitude, conductivity ratio, Prandtl number and the Eckert number on the velocity and/or temperature fields are shown graphically. It is observed that both the velocity and temperature fields in the channel decrease as either of the porous medium parameter or the viscosity ratio increases while they increase with increases in the oscillation amplitude. Also, increasing the thermal conductivity ratio is found to suppress the temperature in both regions of the channel. The effects of the Prandtl and Eckert numbers are found to decrease the thermal state in the channel as well.

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30

Pankratov, V. M., M. A. Barulina, A. V. Golikov, E. V. Pankratova, and M. V. Efremov. "Practical modeling of non-stationary temperature fields of fiber-optic gyroscopes in space flight conditions." E3S Web of Conferences 224 (2020): 02007. http://dx.doi.org/10.1051/e3sconf/202022402007.

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Based on the mathematical model presented in the first part of this paper, specialized software was created and computer modeling of nonstationary inhomogeneous temperature fields in a fiber-optic gyroscope was performed. The simulation aimed to analyze the temperature distribution in the gyroscope structural elements, especially in the fiber-optic coil and the electronics unit, since temperature fluctuations in them are one of the main sources of device errors. To achieve this goal, a three-dimensional unsteady field was calculated in a fiber-optic gyroscope. Based on the results of computer modeling, comparative data on the temperature distribution in the gyroscope structural elements on earth and orbital flight conditions, and the degree of influence of space and zero-gravity conditions are obtained.

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31

Hayat, Tasawar, Yusra Saeed, Sadia Asad, and Ahmed Alsaedi. "Soret and Dufour Effects in the Flow of Williamson Fluid over an Unsteady Stretching Surface with Thermal Radiation." Zeitschrift für Naturforschung A 70, no. 4 (2015): 235–43. http://dx.doi.org/10.1515/zna-2014-0252.

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AbstractThis paper looks at the simultaneous effects of heat and mass transfer in the flow of Williamson fluid over an unsteady stretching surface. The effects of thermal radiation and viscous dissipation are considered in an energy equation. Besides, the energy and concentration equations are coupled with the combined effects of Soret and Dufour. The convective conditions for both temperature and mass concentration are employed. The transformation procedure reduces the time-dependent boundary layer equations of momentum, energy, and concentration to the non-linear ordinary differential equations. Through graphs and numerical values, the velocity, temperature, and concentration fields are discussed for different physical parameters. It is found that the thermal and concentration Biot numbers have an increasing impact on both temperature and concentration fields, respectively.

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32

KATAMINE, Eiji, and Shinya IMAI. "J1240201 Solution to Shape Identification of Unsteady Natural Convection Fields to Control Temperature Distribution." Proceedings of Mechanical Engineering Congress, Japan 2015 (2015): _J1240201——_J1240201—. http://dx.doi.org/10.1299/jsmemecj.2015._j1240201-.

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33

Vatutin, I. A., V. F. Vinokurov, O. G. Martynenko, P. P. Khramtsov, and I. A. Shikh. "VORTICAL STRUCTURES AND TEMPERATURE FIELDS IN UNSTEADY-STATE NATURAL CONVECTION WITHIN A HORIZONTAL TUBE." Experimental Heat Transfer 6, no. 1 (1993): 69–81. http://dx.doi.org/10.1080/08916159208945370.

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34

Ha, Man Yeong, In-Kyu Kim, Hyun Sik Yoon, and Sangsan Lee. "Unsteady fluid flow and temperature fields in a horizontal enclosure with an adiabatic body." Physics of Fluids 14, no. 9 (2002): 3189–202. http://dx.doi.org/10.1063/1.1497168.

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35

Seyed‐Yagoobi, Jamal. "Advanced viscometric thermometer: Steady and unsteady state temperature measurement in electric or magnetic fields." Review of Scientific Instruments 62, no. 1 (1991): 249–50. http://dx.doi.org/10.1063/1.1142272.

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36

Attia, H. A. "Hall current effects on the velocity and temperature fields of an unsteady Hartmann flow." Canadian Journal of Physics 76, no. 9 (1998): 739–46. http://dx.doi.org/10.1139/cjp-76-9-739.

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37

Kuznetsov, G. V., M. V. Piskunov, R. S. Volkov, and P. A. Strizhak. "Unsteady temperature fields of evaporating water droplets exposed to conductive, convective and radiative heating." Applied Thermal Engineering 131 (February 2018): 340–55. http://dx.doi.org/10.1016/j.applthermaleng.2017.12.021.

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38

Pullepu, Bapuji, K. Ekambavanan, and A. J. Chamkha. "Unsteady Laminar Free Convection from a Vertical Cone with Uniform Surface Heat Flux." Nonlinear Analysis: Modelling and Control 13, no. 1 (2008): 47–60. http://dx.doi.org/10.15388/na.2008.13.1.14588.

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Numerical solutions of, unsteady laminar free convection from an incompressible viscous fluid past a vertical cone with uniform surface heat flux is presented in this paper. The dimensionless governing equations of the flow that are unsteady, coupled and non-linear partial differential equations are solved by an efficient, accurate and unconditionally stable finite difference scheme of Crank-Nicolson type. The velocity and temperature fields have been studied for various parameters Prandtl number and semi vertical angle. The local as well as average skin-friction and Nusselt number are also presented and analyzed graphically. The present results are compared with available results in literature and are found to be in good agreement.

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Antonov, Volkov, and Strizhak. "Gas-Vapor Mixture Temperature in the Near-Surface Layer of a Rapidly-Evaporating Water Droplet." Entropy 21, no. 8 (2019): 803. http://dx.doi.org/10.3390/e21080803.

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Mathematical modeling of the heat and mass transfer processes in the evaporating droplet–high-temperature gas medium system is difficult due to the need to describe the dynamics of the formation of the quasi-steady temperature field of evaporating droplets, as well as of a gas-vapor buffer layer around them and in their trace during evaporation in high-temperature gas flows. We used planar laser-induced fluorescence (PLIF) and laser-induced phosphorescence (LIP). The experiments were conducted with water droplets (initial radius 1–2 mm) heated in a hot air flow (temperature 20–500 °С, velocity 0.5–6 m/s). Unsteady temperature fields of water droplets and the gas-vapor mixture around them were recorded. High inhomogeneity of temperature fields under study has been validated. To determine the temperature in the so called dead zones, we solved the problem of heat transfer, in which the temperature in boundary conditions was set on the basis of experimental values.

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Uwanta, I. J., and M. M. Hamza. "Unsteady Flow of Reactive Viscous, Heat Generating/Absorbing Fluid with Soret and Variable Thermal Conductivity." International Journal of Chemical Engineering 2014 (2014): 1–15. http://dx.doi.org/10.1155/2014/291857.

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This study investigates the unsteady natural convection and mass transfer flow of viscous reactive, heat generating/absorbing fluid in a vertical channel formed by two infinite parallel porous plates having temperature dependent thermal conductivity. The motion of the fluid is induced due to natural convection caused by the reactive property as well as the heat generating/absorbing nature of the fluid. The solutions for unsteady state temperature, concentration, and velocity fields are obtained using semi-implicit finite difference schemes. Perturbation techniques are used to get steady state expressions of velocity, concentration, temperature, skin friction, Nusselt number, and Sherwood number. The effects of various flow parameters such as suction/injection (γ), heat source/sinks (S), Soret number (Sr), variable thermal conductivityδ, Frank-Kamenetskii parameterλ, Prandtl number (Pr), and nondimensional timeton the dynamics are analyzed. The skin friction, heat transfer coefficients, and Sherwood number are graphically presented for a range of values of the said parameters.

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Bitter, Martin, Michael Hilfer, Tobias Schubert, Christian Klein, and Reinhard Niehuis. "An Ultra-Fast TSP on a CNT Heating Layer for Unsteady Temperature and Heat Flux Measurements in Subsonic Flows." Sensors 22, no. 2 (2022): 657. http://dx.doi.org/10.3390/s22020657.

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In this paper, the authors demonstrate the application of a modified Ru(phen)-based temperature-sensitive paint which was originally developed for the evaluation of unsteady aero-thermodynamic phenomena in high Mach number but short duration experiments. In the present work, the modified TSP with a temperature sensitivity of up to −5.6%/K was applied in a low Mach number long-duration test case in a low-pressure environment. For the demonstration of the paint’s performance, a flat plate with a mounted cylinder was set up in the High-Speed Cascade Wind Tunnel (HGK). The test case was designed to generate vortex shedding frequencies up to 4300 Hz which were sampled using a high-speed camera at 40 kHz frame rate to resolve unsteady surface temperature fields for potential heat-transfer estimations. The experiments were carried out at reduced ambient pressure of p∞ = 13.8 kPa for three inflow Mach numbers being Ma∞=[0.3;0.5;0.7]. In order to enable the resolution of very low temperature fluctuations down to the noise floor of 10−5 K with high spatial and temporal resolution, the flat plate model was equipped with a sprayable carbon nanotube (CNT) heating layer. This constellation, together with the thermal sensors incorporated in the model, allowed for the calculation of a quasi-heat-transfer coefficient from the surface temperature fields. Besides the results of the experiments, the paper highlights the properties of the modified TSP as well as the methodology.

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Pullepu, B., E. Ekambavanan, and A. J. Chamkha. "Unsteady Laminar Natural Convection from a Non-Isothermal Vertical Cone." Nonlinear Analysis: Modelling and Control 12, no. 4 (2007): 525–40. http://dx.doi.org/10.15388/na.2007.12.4.14684.

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Natural convection effects of the numerical solution for unsteady, laminar, free convection flow over an incompressible viscous fluid past a non-isothermal vertical cone with surface temperature T′w(x) = T′∞ + axn varying as power function of distance from the apex (x = 0) is presented here. The dimensionless governing equations of the flow that are unsteady, coupled and non-linear partial differential equations are solved by an efficient, accurate and unconditionally stable finite difference scheme of Crank-Nicolson type. The velocity and temperature fields have been studied for various parameters Prandtl number, semi vertical angle 0◦ < φ < 90◦ and n. The local as well as average skin-friction and Nusselt number are also presented and analyzed graphically. The present results are compared with available results in literature and are found to be in good agreement.

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O.A., Ajala, Ogundiran S.D., and Salawu S.O. "Unsteady Mixed Convective Flow of Casson Nanofluid in a Darcy-Forchheimer Medium with Slip and Temperature Jump Condition." Unsteady Mixed Convective Flow of Casson Nanofluid in a Darcy-Forchheimer Medium with Slip and Temperature Jump Condition 9, no. 1 (2024): 11. https://doi.org/10.5281/zenodo.10598742.

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Sequel to the need to improve output, there is a growing demand to optimize the thermal conductivity and proficiency of industrial-based fluids. Consequently, viscous non-Newtonian fluids carrying nanoparticles may be utilized as a material to satisfy engineering and industrial demands for increased productivity. This may be applicable to electronic devices, technological devices, biomedical sciences, and other fields. As a result, this work examined unsteady mixed convective flow of Casson nanofluid in a non-Darcy channel with slip and temperature jump constraints. Shooting approach and fourth-order Runge-Kutta method were used to provide the solution to the dimensionless formulated model. Examined are the effects of the ingrained relevant dynamical terms on the flow characteristics, and graphs and tabular presentations of the calculated outcomes are used to elucidate the findings. The study's findings showed that the diffusion of small particles into a fluid boosted thermal conductivity. In addition, the flow rate decreased as the Hartmann number and Forchheimer dynamical term increased. The findings of this study have applications in manufacturing, engineering, and other fields of sciences and technologies. Keywords:- Casson Nanofluid; Darcy-Forchheimer Medium; Mixed Convection; Temperature Jump; Unsteady; Velocity Slip.

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Faisal Khan, Mohammad, Abdulaziz Alorainni, and Rajeev Jha. "Soret and Dufour Effects on an Unsteady MHD Flow through Porous Medium with Hall Current." International Journal of Advance Research and Innovation 4, no. 1 (2016): 191–201. http://dx.doi.org/10.51976/ijari.411629.

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Aim of this paper to investigate Soret (thermal-diffusion) and Dufour (diffusion-thermo) effects on unsteady MHD flow through porous medium in the presence of a magnetic field with hall current. The similarity solutions were obtained using suitable transformations and the resulting similarity ordinary differential equations were solved by finite difference method. The influences of different flow parameters on velocity, temperature and concentration fields are investigated. The skin frictions at the plate due to tangential and lateral velocity fields are obtained in non-dimensional form. The effects of the physical parameters like Dufour number (Du) and Soret number (Sr) on these fields are discussed through graphs and results are physically interpreted.

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Zhou, Shiyu, Jiaqi Cao, Zhili Zhang, Haibo Wang, and Jiying Liu. "Thermal properties of radiant floor surface materials and numerical evaluation of the thermal performance." BioResources 18, no. 2 (2023): 3909–22. http://dx.doi.org/10.15376/biores.18.2.3909-3922.

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A Hot Disk thermal constant analyzer was used to obtain the thermal parameters of composite boards, solid wood floor, and ceramic tiles (CT). FLUENT software was used for the model establishment and the temperature field simulation, and the effects caused by different surface materials were analyzed. A 2D unsteady model was constructed to analyze floor surface temperature and indoor temperature fields in an enclosure space. Comparison of temperature fields caused by different materials showed that both steady indoor temperature and surface temperature of CT were the highest, which is due to its good thermal properties. Thermal conductivity and thermal capacity are the two main factors affecting floor thermal performance in the initial hours, while thermal conductivity is the key factor in the steady period. For the compared floor materials, CT and Sindora glabra (SG) are the optimal choices from the perspective of thermal performance, while composite boards are almost the same in thermal performance.

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Redal, Héctor, Jaime Carpio, Pablo A. García-Salaberri, and Marcos Vera. "DynamFluid: Development and Validation of a New GUI-Based CFD Tool for the Analysis of Incompressible Non-Isothermal Flows." Processes 7, no. 11 (2019): 777. http://dx.doi.org/10.3390/pr7110777.

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A computational fluid dynamics software (DynamFluid) based on the application of the finite element method with the characteristic-based-split algorithm is presented and validated. The software is used to numerically integrate the steady and unsteady Navier–Stokes equations for both constant-density and Boussinesq non-isothermal flows. Benchmark two-dimensional computations carried out with DynamFluid show good agreement with previous results reported in the literature. Test cases used for validation include (i) the lid-driven cavity flow, (ii) mixed convection flow in a vertical channel with asymmetric wall temperatures, (iii) unsteady incompressible flow past a circular cylinder, and (iv) steady non-isothermal flow past a circular cylinder with negligible buoyancy effects. The new software is equipped with a graphical user interface that facilitates the definition of the fluid properties, the discretization of the physical domain, the definition of the boundary conditions, and the post-processing of the computed velocity, pressure and temperature fields.

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Muthucumaraswamy, Rajamanickam, Kailasam Sathappan, and Ramasamy Natarajan. "Diffusion and heat transfer effects on exponentially accelerated vertical plate with variable temperature." Thermal Science 14, no. 1 (2010): 73–77. http://dx.doi.org/10.2298/tsci1001073m.

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An exact solution of unsteady flow past an exponentially accelerated infinite vertical plate with variable temperature has been presented in the presence of uniform mass diffusion. The plate temperature is raised linearly with time and species concentration level near the plate is made to rise Cw. The dimensionless governing equations are solved using Laplace-transform technique. The velocity profiles fields are studied for different physical parameters like thermal Grashof number, mass Grashof number, Schmidt number, a and time. It is observed that the velocity increases with increasing values of a or t.

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LI, Y. R., S. Y. WU, P. LAN, and C. H. FENG. "NATURAL CONVECTION DURING CZOCHRALSKI SINGLE CRYSTAL GROWTH OF SUPERCONDUCTING MATERIALS." Modern Physics Letters B 18, no. 30 (2004): 1533–36. http://dx.doi.org/10.1142/s0217984904008006.

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To understand the characteristics of the flow, heat and mass transfer in the Ba - Cu - O melt for superconducting material YBa 2 Cu 3 O 2-x ( Y 123) single crystal growth by Czochralski method, this paper presents the numerical simulations of the two-dimension unsteady flow, thermal and Y concentration fields in the Ba - Cu - O melt for Y123 single crystal growth. The results show that the flow is steady at a small temperature difference. As the temperature difference in the radial direction increases, the simulation can predict oscillatory flow.

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Wang, Jintang, Baojiang Sun, Weiqing Chen, Jianchun Xu, and Zhiyuan Wang. "Calculation model of unsteady temperature–pressure fields in wellbores and fractures of supercritical CO2 fracturing." Fuel 253 (October 2019): 1168–83. http://dx.doi.org/10.1016/j.fuel.2019.05.111.

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Li, Ming, Guo Qiang Lv, Wen Hui Ma, Hua Wang, and Xi Yang. "Numerical Simulation of an Unsteady Thermal Process in Vacuum Induction Furnace for Metallurgical Grade Silicon Refining." Applied Mechanics and Materials 444-445 (October 2013): 981–85. http://dx.doi.org/10.4028/www.scientific.net/amm.444-445.981.

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The temperature and velocity distribution of melting pool fields is very important effect to the silicon purification in vacuum induction furnace. A numerical model for the electromagnetic-thermal hydrodynamic coupling field has been developed by using the finite element method (FEM) and a two-dimension numerical simulation for temperature of metallurgical-grade silicon melting in vacuum induction furnace was carried out by using a software Multi-physics Comsol 4.2 in this paper. The results showed that the temperature field was dependent on induction heating times and melting pool position and the maximum temperature grads was 400K in constant temperature stage. With the silicon was molted gradually two vortexes were come into being for electromagnetic stirring in the smelting poor.

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