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Готові списки джерел за темами / (p/e); Relative roughness height / Статті в журналах

Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: (p/e); Relative roughness height.

Статті в журналах з теми "(p/e); Relative roughness height"

Автор: Grafiati

Опубліковано: 3 червня 2025

Оновлено: 31 липня 2025

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1

Yadav, Anil Singh, and J. L. Bhagoria. "Modeling and Simulation of Turbulent Flows through a Solar Air Heater Having Square-Sectioned Transverse Rib Roughness on the Absorber Plate." Scientific World Journal 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/827131.

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Анотація:

Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. Use of artificial roughness on a surface is an effective technique to enhance the rate of heat transfer. A CFD-based investigation of turbulent flow through a solar air heater roughened with square-sectioned transverse rib roughness has been performed. Three different values of rib-pitch (P) and rib-height (e) have been taken s

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2

Mishra, Arin, Aman Mehrotra, and S. Senthur Prabu. "Study on Performance Analysis of a Solar Air Heater with Aerofoil Shaped Rib Roughness Using CFD." ECS Transactions 107, no. 1 (2022): 16065–79. http://dx.doi.org/10.1149/10701.16065ecst.

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Анотація:

Present study investigates the heat transfer, friction factor and fluid flow characteristics of fully developed turbulent flow in a rectangular duct of solar air heater having aerofoil shaped rib-roughness on underside of absorber plate. ANSYS 14.5 has been used to simulate air flow through roughened air heater duct. Effect of relative roughness height and roughness pitch on Nusselt number and friction factor of roughened duct have been investigated and compared with that of smooth duct. It is found that the Nusselt number improves by attaching the roughness. Maximum enhancement in Nusselt num

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3

Ajay, Jain, and H. S. Sahu Prof. "CFD Analysis of Solar Air Heater for Enhancenment of Heat Transfer Through Inclined Rib Roughness." International Journal of Trend in Scientific Research and Development 3, no. 1 (2018): 662–67. https://doi.org/10.31142/ijtsrd19057.

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A 3 dimensional CFD analysis has been carried out of solar air heater to study heat transfer and fluid flow behavior in a rectangular duct of a solar air heater with one roughened wall having combination of circular and square transverse wire rib roughness. The effect of Reynolds number, roughness height, roughness pitch, relative roughness pitch and relative roughness height on the heat transfer coefficient and friction factor have been studied. In order to validate the present numerical model, results have been compared with available experimental results under similar flow conditions. CFD I

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4

Stalin, P. Michael Joseph, R. Lokanadham, Gaddam Naveen, et al. "Innovative cinque rib-roughened stimulators on performance improvement in triangular channel solar air heater." International Journal of Low-Carbon Technologies 19 (2024): 224–32. http://dx.doi.org/10.1093/ijlct/ctae002.

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Abstract Present study investigates application of cinque-faced rib roughening to improve the efficiency of solar air heaters (SAHs). Research focuses on a novel design, the cinque-faced rib-roughened triangular channel SAH (CFRTCSAH), which incorporates five-faced wire ribs on the absorber plate’s underside. By breaking down the laminar sublayer and enhancing flow separation and reattachment, - ribs significantly enhance heat transfer. It establishes a comprehensive theoretical model to analyze the thermal and hydraulic performance of the CFRTCSAH. The study considers the influence of paramet

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5

Rana, Jitesh, Anshuman Silori, Rajesh Maithani, and Sunil Chamoli. "Computational fluid dynamics analysis of a V-rib with gap roughened solar air heater." Thermal Science 22, no. 2 (2018): 963–72. http://dx.doi.org/10.2298/tsci160831010r.

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Анотація:

A CFD analysis of a solar air heater has been carried out using V-shaped ribs as artificial roughness on the absorber plate. The relative roughness pitch, P/e = 6-12, Reynolds number of 3800-18000, relative roughness height, e/D = = 0.042, and angle of attack, ? = 30?-75?, have been selected as design variables of V-shaped rib for analysis. The ANSYS FLUENT 15.0 with renormalization group k-? turbulence model is selected for the analysis of computational domain of solar air heater. The enhancement of Nusselt number and friction factor with Reynolds number for different values of a relative rou

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6

Childs, P. R. N., and M. B. Noronha. "1997 John P. Davis Award: The Impact of Machining Techniques on Centrifugal Compressor Impeller Performance." Journal of Turbomachinery 121, no. 4 (1999): 637–43. http://dx.doi.org/10.1115/1.2836715.

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A large proportion of modern centrifugal impellers are machined from solid forgings rather than made from cast metal. The CNC milling process offers options to manufacturers to minimize manufacturing costs while also enhancing the performance of the impeller. Efficient manufacturing can result in cutter tool marks and paths and associated roughness remaining on the hub and blade surfaces of impellers as a result of minimizing passes and maximizing the cut. The goal of manufacturers is to allow these marks to be as deep as possible to minimize machining costs, but without any negative effects o

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7

Placidi, M., and B. Ganapathisubramani. "Effects of frontal and plan solidities on aerodynamic parameters and the roughness sublayer in turbulent boundary layers." Journal of Fluid Mechanics 782 (October 9, 2015): 541–66. http://dx.doi.org/10.1017/jfm.2015.552.

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Experiments were conducted in the fully rough regime on surfaces with large relative roughness height ($h/{\it\delta}\approx 0.1$, where $h$ is the roughness height and ${\it\delta}$ is the boundary layer thickness). The surfaces were generated by distributed LEGO® bricks of uniform height, arranged in different configurations. Measurements were made with both floating-element drag balance and high-resolution particle image velocimetry on six configurations with different frontal solidities, ${\it\lambda}_{F}$, at fixed plan solidity, ${\it\lambda}_{P}$, and vice versa, for a total of twelve r

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8

Ritter, Severin, Kaspar Staub, and Patrick Eppenberger. "Associations between relative body fat and areal body surface roughness characteristics in 3D photonic body scans—a proof of feasibility." International Journal of Obesity 45, no. 4 (2021): 906–13. http://dx.doi.org/10.1038/s41366-021-00758-w.

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Abstract Introduction A reliable and accurate estimate of the percentage and distribution of adipose tissue in the human body is essential for evaluating the risk of developing chronic and noncommunicable diseases. A precise and differentiated method, which at the same time is fast, noninvasive, and straightforward to perform, would, therefore, be desirable. We sought a new approach to this research area by linking a person’s relative body fat with their body surface’s areal roughness characteristics. Materials and methods For this feasibility study, we compared areal surface roughness charact

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9

Khimsuriya, Yogeshkumar D., D. K. Patel, Vivek Patel, Hitesh Panchal, and Lav Kumar Kaushik. "Experimental study of the thermal efficiency of Solar air heater equipped with rotating spiral shape baffles: Using Solar Simulator." Journal of Physics: Conference Series 2818, no. 1 (2024): 012022. http://dx.doi.org/10.1088/1742-6596/2818/1/012022.

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Abstract This study investigates the thermal performance of a Solar Air Heater (SAH) equipped with rotating spiral-shaped baffles, utilizing a solar simulator. Parameters such as relative roughness pitch (P/e) and Reynolds number (Re) were varied within the ranges of 4-10 and 4000-12000, respectively, with a fixed relative roughness height (e/H) of 0.8. The fabricated solar simulator, adhering to EN-12975-2 standards, demonstrated excellent irradiance homogeneity at approximately 10.47%, resulting in an average solar irradiance of 955 W/m2. The introduction of artificial roughness on the absor

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10

Sumit, Kumar*1 and Dr. Manikant Paswan2. "COMPUTATIONAL INVESTIGATION OF THERMAL PERFORMANCE OF SOLAR AIR HEATER HAVING ROUGHNESS ELEMENTS AS TRANSVERSE WIRE ON THE TWO SIDE ABSORBER PLATE." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 7, no. 2 (2018): 664–74. https://doi.org/10.5281/zenodo.1184046.

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An Analytical investigation has been carried out to study the heat transfer and friction characteristics by using a transverse wire on the absorber plate of a solar air heater. The Analytical investigation consist the Reynolds number (Re) ranges from 3000 to 14 000, relative roughness pitch (p/e) 10–30 and relative roughness height (e/D) 0.0135-0.0225. The effect of these parameters on the heat transfer coefficient and friction factor has been discussed in the present paper and correlations for Nusselt number and friction factor has been developed within above limits. A procedure to comp

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11

Alam, Tabish, Chandan Swaroop Meena, Nagesh Babu Balam, Ashok Kumar, and Raffaello Cozzolino. "Thermo-Hydraulic Performance Characteristics and Optimization of Protrusion Rib Roughness in Solar Air Heater." Energies 14, no. 11 (2021): 3159. http://dx.doi.org/10.3390/en14113159.

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Анотація:

To enhance the thermal performance of solar air heaters (SAHs), protrusion ribs on the absorber are considered to be an attractive solution due to their several advantages. These ribs do not cause a significant pressure drop in the SAH duct and help to enhance the heat transfer to flowing air. On the other hand, a degree of roughness of the protrusion rib on the absorber can be produced by pressing the indenting device without adding additional mass. In this paper, the thermo-hydraulic performances of different roughnesses of the conical protrusion rib on the absorber plate have been evaluated

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12

Alaskari, Mustafa, Arwa M. Kadhim, Ammar A. Farhan, Moustafa Al-Damook, and Mansour Al Qubeissi. "Performance Evaluation of Roughened Solar Air Heaters for Stretched Parameters." Clean Technologies 4, no. 2 (2022): 555–69. http://dx.doi.org/10.3390/cleantechnol4020034.

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Artificial roughness applied to a Solar Air Heater (SAH) absorber plate is a popular technique for increasing its total thermal efficiency (ηt−th). In this paper, the influence of geometrical parameters of V-down ribs attached below the corrugated absorbing plate of a SAH on the ηt−th was examined. The impacts of key roughness parameters, including relative pitch p/e (6–12), relative height e/D (0.019–0.043), angles of attack α (30–75°), and Re (1000–20,000), were examined under real weather conditions. The SAH ηt−th roughened by V-down ribs was predicted using an in-house developed conjugate

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13

Piragnolo, M., S. Grigolato, and F. Pirotti. "PLANNING HARVESTING OPERATIONS IN FOREST ENVIRONMENT: REMOTE SENSING FOR DECISION SUPPORT." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-3/W1 (March 1, 2019): 33–40. http://dx.doi.org/10.5194/isprs-annals-iv-3-w1-33-2019.

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<p><strong>Abstract.</strong> The goal of this work is to assess a method for supporting decisions regarding identification of most suitable areas for two types of harvesting approaches in forestry: skyline vs. forwarder. The innovative aspect consists in simulating the choices done during the planning in forestry operations. To do so, remote sensing data from an aerial laser scanner were used to create a digital terrain model (DTM) of ground surface under vegetation cover. Features extracted from the DTM are used as input for several machine learning predictors. Features are

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14

Om, Prakash Srivastava1 K. K. Jain2 Shailesh Gupta3*. "EFFECT OF RIB ATTACK ANGLE ON HEAT TRANSFER AND FRICTION FACTOR IN A SQUARE CHANNEL ROUGHENED BY V SHAPED RIBS WITH A GAP." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 6, no. 12 (2017): 236–44. https://doi.org/10.5281/zenodo.1116631.

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Анотація:

An experimental study was carried out to investigate the effect of angle of attack on forced convection heat transfer and friction factor of an artificially roughened duct. The test section of the square duct (<em>AR</em>=1) was roughened on its top and bottom wall with  V shaped square ribs having a gap on its length. The ratio of the width to height of the duct (<em>W/H</em>) was 1, the relative roughness height (<em>e/D</em><sub>h</sub>) was 0.060, relative roughness pitch (<em>p/e</em>) was 10, relative gap width (<em>g/e</em>) was 1and relative gap position (<em>d/W</em>) was taken a

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15

Dr., Ashwini Kumar*. "A REVIEW REPORT FOR HEAT TRANSFER AND FLUID FLOW CHARECTRISTICS." Global Journal of Engineering Science and Research Management 4, no. 10 (2017): 98–120. https://doi.org/10.5281/zenodo.1034495.

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Анотація:

Solar air heaters are one of the simplest and cost effective solar energy utilization systems for various drying applications. The thermal efficiency of solar air heaters is found to be low due to low heat transfer coefficient on the air side. Attempts have been made to enhance the heat transfer rate from the absorber plate to air by using different roughness elements. Enhancement of heat transfer coefficient is achieved by providing artificial roughness, always goes with an increment of pressure drop and more pumping power is required. So, there is a need to optimize the system parameters to

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16

Ayalew, Yewondwosen Gzate. "Experimental Investigation of Heat and Fluid Flow Characteristics on Expanded Metal Mesh Roughened Solar Collector." Trends in Sciences 19, no. 22 (2022): 6326. http://dx.doi.org/10.48048/tis.2022.6326.

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Solar air heater is used for agricultural grain products drier, curing of industrial products and for other systems requiring low grade thermal energy. Their usefulness and quantitative energy collections has been limited. This is because of low thermal efficiency with primarily as a result of low convective heat transfer coefficient, between the absorber plate and air leading to higher plate temperature. This results greater thermal energy losses. Experimental investigation has been conducted to study heat transfer enhancement by using small diameter wire ribs on absorber plate of solar air h

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17

Gawande, Vipin B., A. S. Dhoble, and D. B. Zodpe. "CFD Analysis to Study Effect of Circular Vortex Generator Placed in Inlet Section to Investigate Heat Transfer Aspects of Solar Air Heater." Scientific World Journal 2014 (2014): 1–11. http://dx.doi.org/10.1155/2014/567257.

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Анотація:

CFD analysis of 2-dimensional artificially roughened solar air heater duct with additional circular vortex generator, inserted in inlet section is carried out. Circular transverse ribs on the absorber plate are placed as usual. The analysis is done to investigate the effect of inserting additional vortex generator on the heat transfer and flow friction characteristics inside the solar air heater duct. This investigation covers relative roughness pitch in the range of 10 ≤P/e≤ 25 and relevant Reynolds numbers in the range of 3800 ≤ Re ≤ 18000. Relative roughness height (e/D) is kept constant as

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18

Kant, Chander, Prashant Kumar, Ankur Gill, and Dhiraj Parkash Dhiman. "Thermal Performance of Three Sided Artificially Roughened Double Duct Parallel Flow Solar Air Heater." Asian Journal of Engineering and Applied Technology 7, no. 1 (2018): 5–15. http://dx.doi.org/10.51983/ajeat-2018.7.1.976.

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Анотація:

A solar air heater is basically a heat exchanger, which intercepts the incident solar radiation, converts it into heat and finally transfers this heat to a working fluid for an end use system. The mode of air flowing in the ducts of a solar air heater is one of the most significant aspects concerned with solar air heater which dominantly affect. A double duct parallel flow artificially roughened solar air heater with three sides of the absorber plate is investigated in the current study. Unlike the conventional model of solar air heater with only one sided roughened absorber plate, a novel sol

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19

Kalpana, Soni*1 &. Surendra Bharti2. "CFD ANALYSIS OF SOLAR AIR HEATER FOR ENHANCEMENT OF HEAT TRANSFER." INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY 6, no. 6 (2017): 430–44. https://doi.org/10.5281/zenodo.814587.

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Анотація:

Energy is the basic ingredient to sustain life and development. Work means moving or lifting something, warming or lighting something. There are many sources of energy that help to run the various machines invented by man.A 3-dimensional CFD analysis has been carried out to study heat transfer and fluid flow behavior in a rectangular duct of a solar air heater with one roughened wall having combination of circularand square transverse wire rib roughness. The effect of Reynolds number, roughness height, roughness pitch, relative roughness pitch and relative roughness height on the heat transfer

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20

Wang, Hong Cai, and Yang Wang. "The Height Amplitudes of Surface Roughness Based on Area-Direction Character and Relative Assessed Indexes." Advanced Materials Research 482-484 (February 2012): 1150–54. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1150.

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To study the relationship among the height amplitude of surface roughness , assessed area and assessed direction, the height amplitudes SRa, SRq, SRsk and SRku based on area-direction character are defined in the paper. And on the foundation of these parameters, relative assessed area indexes, assessed direction indexes and assessed total indexes are established. SRa, SRq, SRsk and SRku are the natural extension of 2D height amplitudes Ra, Rq, Rsk and Rku. They are different from 3D height amplitudes Sa, Sq, Ssk and Sku. They provide an evidence to study the quantitative relationship among sur

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21

GAMRAT, G., M. FAVRE-MARINET, S. LE PERSON, R. BAVIÈRE, and F. AYELA. "An experimental study and modelling of roughness effects on laminar flow in microchannels." Journal of Fluid Mechanics 594 (December 14, 2007): 399–423. http://dx.doi.org/10.1017/s0022112007009111.

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Three different approaches were used in the present study to predict the influence of roughness on laminar flow in microchannels. Experimental investigations were conducted with rough microchannels 100 to 300μm in height (H). The pressure drop was measured in test-sections prepared with well-controlled wall roughness (periodically distributed blocks, relative roughness k* =k/0.5H≈0.15) and in test-sections with randomly distributed particles anchored on the channel walls (k* ≈0.04–0.13). Three-dimensional numerical simulations were conducted with the same geometry as in the test-section with p

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22

Hu, Yandong, Carsten Werner, and Dongqing Li. "Influence of Three-Dimensional Roughness on Pressure-Driven Flow Through Microchannels." Journal of Fluids Engineering 125, no. 5 (2003): 871–79. http://dx.doi.org/10.1115/1.1598993.

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Surface roughness is present in most of the microfluidic devices due to the microfabrication techniques or particle adhesion. It is highly desirable to understand the roughness effect on microscale flow. In this study, we developed a three-dimensional finite-volume-based numerical model to simulate pressure-driven liquid flow in microchannels with rectangular prism rough elements on the surfaces. Both symmetrical and asymmetric roughness element arrangements were considered, and the influence of the roughness on pressure drop was examined. The three-dimensional numerical solution shows signifi

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23

Behura, Aruna Kumar, Chinmaya Prasad Mohanty, Manas Ranjan Singh, Ashwini Kumar, Emanoil Linul, and Dipen Kumar Rajak. "Performance Analysis of Three Side Roughened Solar Air Heater: A Preliminary Investigation." Materials 15, no. 7 (2022): 2541. http://dx.doi.org/10.3390/ma15072541.

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In recent years, sunlight has been used in several fields such as photovoltaic cells, flat plate collectors, solar cookers, green buildings, and agricultural applications. Improved thermal performance has been seen which comes of three sides absorber plate with glass cover compared to the traditional one. This paper presents the Nusselt (Nu) number, collector efficiency factor (CEF), and collector heat removal factor (CHRF) for the optimal solution of three sides artificially roughened solar air heater. Five input variables such as Reynolds (Re) number, relative roughness pitch, relative rough

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24

YANG, SHANSHAN, HUAHUA FU, and BOMING YU. "FRACTAL ANALYSIS OF FLOW RESISTANCE IN TREE-LIKE BRANCHING NETWORKS WITH ROUGHENED MICROCHANNELS." Fractals 25, no. 01 (2017): 1750008. http://dx.doi.org/10.1142/s0218348x17500086.

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In this work, the effective average height of the roughness elements, the relative increase of the pressure gradients, the relative decrease of the permeability are derived based on the fractal geometry theory and technique for laminar flow through tree-like branching networks with roughened channels. The relationships among the effective average height, the structural parameters and pressure drops as well as permeability are studied. It is found that the total pressure drop across a tree-like branching network with roughened channels is increased by a factor of [Formula: see text], and the pe

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25

Ajay, Jain, and S. Sahu H. "CFD Analysis of Solar Air Heater Provided with Discrete Inclined Rib Roughness on the Absorber Plate A Review." International Journal of Trend in Scientific Research and Development 2, no. 6 (2018): 703–6. https://doi.org/10.31142/ijtsrd18686.

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Heat transfer enhancement is a subject of considerable interest to researchers as it leads to saving in energy and cost. Because of the rapid increase in energy demand in all over The world, both reducing energy lost related with ineffective use and enhancement of energy in the meaning of heat have become an increasingly significance task for design and operation engineers for many system. A 3 dimensional CFD analysis has been carried out to study heat transfer and fluid flow behavior in a rectangular duct of a solar air heater with one roughened wall having discrete inclined rib roughness. Th

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26

Ding, Lei, and Qing-He Zhang. "LATTICE BOLTZMANN SIMULATION TO CHARACTERIZE ROUGHNESS EFFECTS OF OSCILLATORY BOUNDARY LAYER FLOW OVER A ROUGH BED." Coastal Engineering Proceedings 1, no. 32 (2011): 3. http://dx.doi.org/10.9753/icce.v32.sediment.3.

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The 3-D lattice Boltzmann method was applied to characterize roughness effects of oscillatory boundary layer flow over a rough bed. The direct numerical simulation was carried out and the flow resistance of the flat and fixed bed was investigated. The position of the theoretical bed, equivalent roughness height and the behavior of friction factor at small values of relative roughness were obtained using the log-fit method.

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27

Wang, Zhihui, Xuguang Yang, Xiaohua Gu, et al. "Investigating Enhanced Convection Heat Transfer in 3D Micro-Ribbed Tubes Using Inverse Problem Techniques." Energies 17, no. 20 (2024): 5102. http://dx.doi.org/10.3390/en17205102.

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The improved heat dissipation observed in 3D micro-ribbed tubes is primarily influenced by the intricate interplay of multiple structural parameters. Nevertheless, research into the coupling mechanisms of these multi-structural parameters remains constrained by the absence of effective methodology in numerical solutions. In the present work, a new 3D micro-rib structure based on discrete adjoint method is established. Firstly, the research examines the interplay of different parameters (such as arrangement, relative roughness height, angle of attack, and circumferential rows) on the thermo-hyd

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28

Liu, Yanming, Jiahe Li, and Alexander J. Smits. "Roughness effects in laminar channel flow." Journal of Fluid Mechanics 876 (August 15, 2019): 1129–45. http://dx.doi.org/10.1017/jfm.2019.603.

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Анотація:

The effects of roughness on the frictional drag and pressure drop in laminar channel flow are investigated numerically. The inflow is fully developed smooth wall flow, and square rib roughness, aligned normal to the bulk flow direction, is introduced as a step change. The roughness height and spacing are systematically varied, and the flow is examined as it develops over the rough wall and becomes fully developed. The length of the development region depends primarily on the roughness height, although the effects of spacing become more important as the height decreases. In the fully developed

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29

Hans, V. S., R. S. Gill, and Rupinderpal Singh. "Effect of rib roughness pitch on thermal and thermo-hydraulic performance of a solar air heater roughened artificially with arc rib having gap." Journal of Applied and Natural Science 8, no. 1 (2016): 251–56. http://dx.doi.org/10.31018/jans.v8i1.782.

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Анотація:

This experimental study on a solar air heater having absorber plate roughened artificially by providing roughness in the form of arc ribs having gap was carried out in the Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana, India to study the effect of relative roughness pitch on thermal and thermohydraulic performance as well as to compare the performance of arc rib with gap roughened solar air heater with that of continuous arc rib roughened solar air heater. The roughness geometry parameters included relative roughness height of 0.043, angle of attack of 30 degre

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30

Dejam, Morteza, Hassan Hassanzadeh, and Zhangxin Chen. "Shear Dispersion in a Rough-Walled Fracture." SPE Journal 23, no. 05 (2018): 1669–88. http://dx.doi.org/10.2118/189994-pa.

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Summary An expression is analytically presented for the shear dispersion, or Taylor (1953) and Aris (1956) dispersion, of a solute transporting in a coupled system, which consists of a matrix and a rough-walled fracture. To derive a shear-dispersion coefficient in a fracture with rough and porous walls, the continuities of solute concentrations and their fluxes are imposed at the fracture walls. The dispersion coefficient for the coupled system is obtained as a function of the Péclet number and relative roughness, where the latter parameter is defined as the ratio of the maximum height of the

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31

Taniyasu, Kanta, Ryutaro Tanaka, Isaí Espinoza Torres, Israel Martínez Ramírez, Katsuhiko Sekiya, and Keiji Yamada. "Improvement of Prediction Reliability of Tool Edge Contour Position in Turning ― Influence of Boundary Wear on Process of Dividing Roughness Curve into Feed Marks in Estimating Roughness Components." Defect and Diffusion Forum 441 (March 26, 2025): 75–81. https://doi.org/10.4028/p-4pk9w7.

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It is well known that the surface roughness in turning consists of the theoretical roughness, vibration in the depth of cut direction, and overcutting by adhered work material. Some of authors had already proposed the method to calculate surface roughness components. In this method, the approximate arc was used as a representative tool contour of the tool contour to dividing roughness curve into each feed marks. The arc was defined by the height of the intersection of the measured tool contours set at feed intervals horizontally. However, when the boundary wear occurred in the finished surface

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32

Yang, X., R. Y. Gu, D. Y. Xing, Z. D. Wang, and Jinming Dong. "Tunneling Magnetoresistance in Ferromagnet/Insulator/Ferromagnet Junctions." International Journal of Modern Physics B 11, no. 28 (1997): 3375–84. http://dx.doi.org/10.1142/s0217979297001659.

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A δ-type potential with complex prefactor is modeled on the tunneling barrier of a thin insulator (I) film separating two ferromagnetic (FM) films. By matching value and slope of wave functions across the tunneling barrier of a FM/I/FM junction, we obtain a general expression for tunneling conductance as a function of relative orientation θ between magnetizations of the two ferromagnets, barrier height and interface roughness. It is shown that the magnitude of tunneling magnetoresistance is strongly dependent on θ, but much less affected by the barrier height and the interface roughness.

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33

Sayyadi, Keikhosro, Manouchehr Heidarpour, and Zahra Ghadampour. "Effect of Bed Roughness and Negative Step on Characteristics of Hydraulic Jump in Rectangular Stilling Basin." Shock and Vibration 2022 (August 5, 2022): 1–9. http://dx.doi.org/10.1155/2022/1722065.

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Water flow often releases excess energy after passing through gates and spillways. This energy should be reduced to avoid the destruction of downstream structures. The hydraulic jump, a natural phenomenon, inevitably reduces incoming flow energy. The experiments were carried out in this study to investigate the effect of bed roughness and abrupt negative drops on the characteristics of the hydraulic jump. Also, to investigate the effect of geometric and hydraulic parameters on energy dissipation and location of the hydraulic jump, there was a change in the height of the abrupt drop and roughne

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34

Arzikulov, E. U., A. D. Nurimov, S. Q. Axrorov, and N. Mamatqulov. "A study of surface morphology of Fe/p-Si hybrid structure using atom force microscope." Journal of Physics: Conference Series 2573, no. 1 (2023): 012016. http://dx.doi.org/10.1088/1742-6596/2573/1/012016.

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Abstract p-Si substrate was cleaned by chemical means. After the cleaning, iron thin film was deposited on the silicon substrate by electron beam evaporation method with high purity Fe target. Then, the roughness parameters of the sample after chemical cleaning and after obtaining a thin layer were compared. Surface roughness measurement of the iron thin film in the nanometer scale can be accurately determined using the AFM. Apart from the average roughness, all the roughness parameters of the surface increased. The average roughness, average height, root mean square roughness, and other param

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35

Carvalho, Gabriel Ferraz Marcondes de, Marília Fernandes Vidille, Alex Mendonça Bimbato, and Luiz Antonio Alcântara Pereira. "Lagrangian Vortices Interactions Using Large-Eddy Simulation (LES) and Surface Roughness Model—Application for Aircraft Wake Vortices with Crosswind." Applied Sciences 13, no. 22 (2023): 12336. http://dx.doi.org/10.3390/app132212336.

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A new technique for two-dimensional vortex methods is presented. The vorticity field is discretized and represented by vortex blobs. Viscosity and roughness are incorporated into vortex simulations by means of the corrected core-spreading method with LES theory. A deterministic and efficient grid-free method simulates viscous effects by maintaining small vortex core sizes through a splitting algorithm that controls the consistency error. The LES theory also enables the implementation of the roughness model. The effectiveness of this method is shown in calculating vortex interactions and decay

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36

HABIB, Saqib, Norio TANAKA, and Yuta YOSHIZAWA. "OPEN CHANNEL TURBULENCE CHARACTERISTICS IN A ROUGHNESS LAYER FOR SMALL WATER DEPTH RELATIVE TO ROUGHNESS ELEMENTS HEIGHT." Journal of Japan Society of Civil Engineers, Ser. B1 (Hydraulic Engineering) 72, no. 4 (2016): I_511—I_516. http://dx.doi.org/10.2208/jscejhe.72.i_511.

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37

AlSunbul, Hanan, Khold AlAhdal, Arwa AlMashhaf, Hind AlHaidry, and Alhanouf AlAmeel. "Wear and surface roughness of commercially available computer-aided design/computer-aided manufacturing dental ceramic materials." Materials Express 12, no. 10 (2022): 1302–7. http://dx.doi.org/10.1166/mex.2022.2261.

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The study evaluated in vitro two-body wear and surface roughness of the recently introduced CAD/CAM dental materials. Pin-on-disk design was set against each other horizontally at a fixed distance with 5 kg (49 N) in distilled water. CAD/CAM materials used were: Feldspathic ceramic (Vitablocks Mark II), lithium disilicate (IPS e.max CAD), hybrid ceramic (Vita Enamic) and zirconia-reinforced glass ceramic (Vita Suprinity PC). Wear evaluation before and after the chewing cycles were performed by two approaches: weight and vertical height measurements. The surface roughness of the tested material

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38

Prasad, Radha K., and Mukesh K. Sahu. "Entropy generation and thermodynamic analysis of solar air heaters with artificial roughness on absorber plate." Archives of Thermodynamics 38, no. 3 (2017): 23–48. http://dx.doi.org/10.1515/aoter-2017-0014.

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AbstractThis paper presents mathematical modelling and numerical analysis to evaluate entropy generation analysis (EGA) by considering pressure drop and second law efficiency based on thermodynamics for forced convection heat transfer in rectangular duct of a solar air heater with wire as artificial roughness in the form of arc shape geometry on the absorber plate. The investigation includes evaluations of entropy generation, entropy generation number, Bejan number and irreversibilities of roughened as well as smooth absorber plate solar air heaters to compare the relative performances. Furthe

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39

Ahmaddani, Restiawan, and Khusna Dwijayanti. "Design of Experiment for Determining Setting Parameter on Plasma Arc Machining for Stainless Steel Plate Cutting with Full Factorial Design." Key Engineering Materials 978 (March 27, 2024): 11–23. http://dx.doi.org/10.4028/p-bxul3c.

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Plasma Arc Machining is a metal cutting where conductor metal such as sheets metal are cut with plasma arc. Problem in plasma arc machining is the result of cutting has burr which is quite large due to the heat, resulting the surface roughness on the workpiece. This research aim to minimize the surface roughness of the stainless steel plate uses a design of experiment method with full factorial design. In this research, there are three factors, that are torch height, cutting speed, and electric current. Each factor has three levels. By using full factorial design, the number of treatments are

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40

Kanda, M., M. Kanega, T. Kawai, R. Moriwaki, and H. Sugawara. "Roughness Lengths for Momentum and Heat Derived from Outdoor Urban Scale Models." Journal of Applied Meteorology and Climatology 46, no. 7 (2007): 1067–79. http://dx.doi.org/10.1175/jam2500.1.

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Abstract Urban climate experimental results from the Comprehensive Outdoor Scale Model (COSMO) were used to estimate roughness lengths for momentum and heat. Two different physical scale models were used to investigate the scale dependence of the roughness lengths; the large scale model included an aligned array of 1.5-m concrete cubes, and the small scale model had a geometrically similar array of 0.15-m concrete cubes. Only turbulent data from the unstable boundary layers were considered. The roughness length for momentum relative to the obstacle height was dependent on wind direction, but t

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41

Chan, L., M. MacDonald, D. Chung, N. Hutchins, and A. Ooi. "A systematic investigation of roughness height and wavelength in turbulent pipe flow in the transitionally rough regime." Journal of Fluid Mechanics 771 (April 27, 2015): 743–77. http://dx.doi.org/10.1017/jfm.2015.172.

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Direct numerical simulations (DNS) are conducted for turbulent flow through pipes with three-dimensional sinusoidal roughnesses explicitly represented by body-conforming grids. The same viscous-scaled roughness geometry is first simulated at a range of different Reynolds numbers to investigate the effects of low Reynolds numbers and low $R_{0}/h$, where $R_{0}$ is the pipe radius and $h$ is the roughness height. Results for the present class of surfaces show that the Hama roughness function ${\rm\Delta}U^{+}$ is only marginally affected by low Reynolds numbers (or low $R_{0}/h$), and observati

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42

Benabid, Seyfeddine, Sonia Cherhabil, Abdelkader Ouakouak, and Ali Bedjaoui. "Characteristics of hydraulic jump in asymmetrical trapezoidal channel with rough beds: experimental investigations." STUDIES IN ENGINEERING AND EXACT SCIENCES 5, no. 2 (2024): e11610. https://doi.org/10.54021/seesv5n2-630.

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Understanding the dynamics of hydraulic jumps is crucial for optimizing the design of stilling basins in dams, enhancing energy dissipation efficiency, and reducing corrosion risks in hydraulic structures. This work aims to investigate the effect of bed geometry and roughness on the properties of hydraulic jump in an asymmetric trapezoidal channel, including parameters such as sequential depths, roller length and energy loss. Experiments were carried out under open channel flow conditions using three different bottom roughness element heights and mm. The channel's bottom is inclined transverse

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43

Kholil, Ahmad, Eko Arif Syaefuddin, Agung Premono, and Farhan Nugraha. "The Effect of Orientation Angle and Layer Thickness on Surface Roughness of ABS Material on FDM." Materials Science Forum 1057 (March 31, 2022): 3–10. http://dx.doi.org/10.4028/p-m37s90.

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Surface roughness of ABS material on FDM process due to different orientation angle and layer thickness are investigated using an experimental method. The aim of this paper is to determine the effect of orientation angle and layer thickness on surface roughness on 3-dimension FDM printing on ABS material. A rectangle model with 60 mm length,10 mm in width, and 10 mm in height is used in this research. The orientation angle of model is 30, 45, and 60 degrees in layer thickness of 0.15 mm and 0.25 mm. The results indicates that the different orientation angle of the layer thickness causes the ro

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44

Kiran Kumar. B et al.,, Kiran Kumar B. et al ,. "Study of Relative Roughness Pitch and Height on Heat Transfer Coefficient of Solar Air Heater with Artificial Roughness." International Journal of Mechanical and Production Engineering Research and Development 8, no. 5 (2018): 409–16. http://dx.doi.org/10.24247/ijmperdoct201846.

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45

Shiba, Shamiran Jargess, Naeema Thaher Aaref, and Shaker A. Jalil. "Properties of Hydraulic Jump on Horizontal Rough Beds." Zanin Journal of Science and Engineering 1, no. 2 (2025): 01–09. https://doi.org/10.64362/zjse.22.

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Анотація:

Hydraulic jumps are essential for dissipating the kinetic energy of high-velocity flows downstream of hydraulic structures such as spillways, drops, chutes, and gates. Effective energy dissipation is critical to prevent scouring and structural damage, and one of the most influential factors in enhancing this dissipation is the roughness of the stilling basin floor. This study investigates how varying bed roughness affects hydraulic jump characteristics in open channel flow. Five-bed conditions were tested, including a smooth surface and four different gravel bed roughness heights: 1.13 cm, 1.5

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46

Lin, Li Jung, and Bing Yue Tsui. "Influence of Post-Ion-Implantation Annealing Temperature on the Characteristics of Gate Oxide on 4H Silicon Carbide." Materials Science Forum 1090 (May 31, 2023): 107–11. http://dx.doi.org/10.4028/p-se77bl.

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The effect of post-ion implantation annealing on the properties of the SiO2/4H-SiC interface is examined in this paper. It is observed that the surface roughness degrades after the high-temperature Ar annealing, but the oxidation process after the high temperature annealing can improve the surface roughness. To better understand the effect of high-temperature annealing on the gate oxide, the reliability of gate oxide is further studied. The results show that although the surface roughness degrades after high-temperature annealing, the interface state density, tunneling barrier height, breakdow

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47

Singh, Jitendra, and Atul Lanjewar. "Thermal performance of solar air heater having discrete symmetrical arc rib with staggered rib roughness." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, May 15, 2023, 095440622311707. http://dx.doi.org/10.1177/09544062231170706.

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This paper investigates physics of forced flow underneath the absorber plate in solar air heater (SAH) integrated with new arc geometry namely discrete symmetrical arc rib with staggered rib roughness. This article signifies the impact of roughness pitch relative to rib height (p/e) on the thermal performance of rectangular roughened SAH duct having discrete symmetrical arc rib with staggered rib (present study). Novel arc rib geometry (present study) is achieved by providing an additional gap in a significantly long continuous arc segment of existing best arc rib geometry to break the boundar

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48

-, Kalpana, L. Varshney, and sudhakar subudhi. "Heat transfer and pressure drop in a double pass solar air heater with arc shaped artificial roughness." Journal of Solar Energy Engineering, April 21, 2022, 1–37. http://dx.doi.org/10.1115/1.4054397.

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Abstract An experimental and theoretical study has been performed to analyze the heat transfer and pressure drop performance of a double pass solar air heater having arc shaped roughness. The investigations are performed for the Re ranging from 3000-12000, relative roughness pitch (p/e) ranging from 8-12, relative roughness height (e/d) of 0.0433 and the angle of attack (a/90) of 0.3333. The investigation has covered different performance parameters such as Nu, friction factor and thermal performance factor of rough and smooth double pass solar air heater. The significant enhancement is observ

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49

"Performance Evaluation of Solar Collector Having Broken Arc Ribs Of Symmetrical Gap with Staggered Elements." International Journal of Engineering and Advanced Technology 9, no. 1 (2019): 7611–15. http://dx.doi.org/10.35940/ijeat.f9317.109119.

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To experimentally investigate the thermal behaviour of solar collector with broken arc artificial roughness of symmetrical gap and staggered element, a study is conducted with four number of absorber surface of hot rolled steel plate of dimensions 1500 mm x210 mm x1.2 mm (length x width x thickness). The test dimension of plate was 1500 mm x 200 mm (LxW). The test parameters were relative roughness pitch P/e as 8-14, relative roughness height e/Dh as 0.04545, number of gaps Ng as 2, relative gap width g/e as 1, relative staggered length r/e as 4.5, relative staggered pitch p’/p as 0.4 and Reyn

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50

Singh, Dharam, and Vikash Kumar. "Thermohydraulic performance parameter based experimental investigation of frustum shaped roughened solar air heater." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, January 28, 2024. http://dx.doi.org/10.1177/09576509241227754.

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An outdoor experimental investigation was conducted to explore the thermohydraulic characteristic (Nusselt no. and friction factor) of artificial roughened solar air heater (ARSAH) having frustrum shaped roughened element on absorber plate. Data were recorded and further processed to generate Nusselt number and friction factor correlation to predict the effect of flow and roughness parameter on performance of ARSAH. The investigation was conducted by varying Reynolds number in range of 2500–12,500. Dimensionless parameter for Frustrum shaped roughness was relative frustum height (e/Dh) from 0.

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