Triangular Corrugations Research Articles

Design and analysis of D-shaped fiber optic plasmonic sensors using triangular corrugation of silver: transmittance and field analysis

In this study, the wave optics module of COMSOL Multiphysics is used to simulate a D-shaped optical fibre plasmonic sensor with triangular corrugation structures made of silver. The transmittance and electric field-based performance defining parameters i.e., resonance wavelength (λ r), shift in resonance wavelength (∆λ r), minimum transmittance (Tmin), bandwidth (BW), penetration depth (PD), and propagation length (PL) are examined. The obtained sensitivity of the proposed sensor is 10.2 μm RIU−1. It is seen that the proposed sensor structure increases the sensitivity by 41% with respect to planar Ag and 40.2% with respect to rectangular grating of Ag. Also, the PD increases 36.6% with respect to planar Ag and 30% with respect to rectangular grating Ag.

A case study on entropy generation in MHD nanofluid flow in L- shaped triangular corrugated permeable enclosure

Enclosure with irregular boundaries by providing surface corrugations is considered an efficient strategy to elevate the heat transfer mechanism in laser technology, cooling of electronic instrument, photonic systems in material processing, magnetic resonance, and the automobile industry are few to mention. In view of such mesmerizing utilization present work is articulated by considering L-shaped corrugated enclosure saturated with water and copper (Cu) nanoparticles are included. The physical impacts of a horizontally oriented magnetic field and permeable medium are accounted along with measurement of entropy. Mathematical modelling of the problem is attained in dimensionless version through a set of similar variables. Computational experiments are conducted through the application of commercial software (COMSOL) based on the finite element approach. A grid independence and comparison tests are also accounted to ensure credibility of simulations. Impact of parameters is revealed through sketches. Quantities of interest, including local and average Nusselt numbers, Bejan number, and total entropy, are also evaluated for flat and correlated surfaces. Induction of nanoparticles in the base fluids tends to reduce the entropy generation by up to 12.45 %. Growth in NuAvg (3.08 % approx.) is attained by increasing the frequency of imposed triangular waved corrugation.

Numerical investigation of three-dimensional natural convection heat transfer on corrugated plates of variable height

PurposeThe purpose of this study is to numerically investigate the geometric influence of different corrugation profiles (rectangular, trapezoidal and triangular) of varying heights on the flow and the natural convection heat transfer process over isothermal plates.Design/methodology/approachThis work is an extension and finalization of previous studies of the leading author. The numerical methodology was proposed and experimentally validated in previous studies. Using OpenFOAM® and other free and open-source numerical-computational tools, three-dimensional numerical models were built to simulate the flow and the natural convection heat transfer process over isothermal corrugation plates with variable and constant heights.FindingsThe influence of different geometric arrangements of corrugated plates on the flow and natural convection heat transfer over isothermal plates is investigated. The influence of the height ratio parameter, as well as the resulting concave and convex profiles, on the parameters average Nusselt number, corrected average Nusselt number and convective thermal efficiency gain, is analyzed. It is shown that the total convective heat transfer and the convective thermal efficiency gain increase with the increase of the height ratio. The numerical results confirm previous findings about the predominant effects on the predominant impact of increasing the heat transfer area on the thermal efficiency gain in corrugated surfaces, in contrast to the adverse effects caused on the flow. In corrugations with heights resulting in concave profiles, the geometry with triangular corrugations presented the highest total convection heat transfer, followed by trapezoidal and rectangular. For arrangements with the same area, it was demonstrated that corrugations of constant and variable height are approximately equivalent in terms of natural convection heat transfer.Practical implicationsThe results allowed a better understanding of the flow characteristics and the natural convection heat transfer process over isothermal plates with corrugations of variable height. The advantages of the surfaces studied in terms of increasing convective thermal efficiency were demonstrated, with the potential to be used in cooling systems exclusively by natural convection (or with reduced dependence on forced convection cooling systems), including in technological applications of microelectronics, robotics, internet of things (IoT), artificial intelligence, information technology, industry 4.0, etc.Originality/valueTo the best of the authors’ knowledge, the results presented are new in the scientific literature. Unlike previous studies conducted by the leading author, this analysis specifically analyzed the natural convection phenomenon over plates with variable-height corrugations. The obtained results will contribute to projects to improve and optimize natural convection cooling systems.

Boosting storage collector efficiency with new corrugated absorbers: A numerical simulation approach

This paper presents a numerical investigation of the performance of a rectangular storage solar collector with three different absorber plate shapes: smooth, parabolic, and triangular. The research employs three-dimensional, unsteady modeling using COMSOL software version 5.5 to simulate a solar storage collector system in Kufa-Najaf's climatic conditions. Two days in November and July were selected to evaluate the system's performance under various atmospheric conditions. The results showed that the highest water temperature for a no-load condition was 36.2 °C in November and 51.7 °C in July. For a triangular corrugation absorber storage collector under load, the largest temperature difference between the outflow and inflow temperatures was 14.9 °C at 1 p.m. and 11.9 °C at sunset in November, while the maximum temperature difference was 13.4 °C at 4 p.m. in July. The study also found that the total efficiency of the triangular corrugation absorber storage collector was higher than that of the other designs, and generally, the total efficiency under no-load conditions was lower than the load. The present work offers a novel solar storage collector configuration with a parabolic or triangular roughened integrated plate absorber, which enhances heat transfer, promoting energy efficiency and improving outlet water temperature.

The Effect of Random Roughness on the Electromagnetic Flow in a Micropipe.

The features of stationary random processes and the small parameter expansion approach are used in this work to examine the impact of random roughness on the electromagnetic flow in cylindrical micropipes. Utilizing the perturbation method, the analytical solution until second order velocity is achieved. The analytical expression of the roughness function ζ, which is defined as the deviation of the flow rate ratio with roughness to the case having no roughness in a smooth micropipe, is obtained by integrating the spectral density. The roughness function can be taken as the functions of the Hartmann number Ha and the dimensionless wave number λ. Two special corrugated walls of micropipes, i.e., sinusoidal and triangular corrugations, are analyzed in this work. The results reveal that the magnitude of the roughness function rises as the wave number increases for the same Ha. The magnitude of the roughness function decreases as the Ha increases for a prescribed wave number. In the case of sinusoidal corrugation, as the wave number λ increases, the Hartmann number Ha decreases, and the value of ζ increases. We consider the λ ranging from 0 to 15 and the Ha ranging from 0 to 5, with ζ ranging from -2.5 to 27.5. When the λ reaches 15, and the Ha is 0, ζ reaches the maximum value of 27.5. At this point, the impact of the roughness on the flow rate reaches its maximum. Similarly, in the case of triangular corrugation, when the λ reaches 15 and the Ha is 0, ζ reaches the maximum value of 18.7. In addition, the sinusoidal corrugation has a stronger influence on the flow rate under the same values of Ha and λ compared with triangular corrugation.

An experimental and numerical approach for optimization of internal and external corrugations with various geometries in cylindrical thin-walled concertina energy absorbers under quasi-static axial load

Thin-walled tubes have been extensively used as energy absorbers in many engineering structures that are under dynamic or quasi-static loads. In this article, the effect of corrugation and its geometry on the collapse characteristics of aluminum concertina tubes under quasi-static axial load is investigated both experimentally and numerically. The numerical simulations were performed with the use of LS-Dyna commercial software. Then, several chosen samples were tested experimentally to verify the results of the simulation. Forty different samples with four different corrugation geometries including singly isosceles triangular corrugation, continual isosceles triangular corrugation, continual scalene triangular corrugation, and continual semi-circular corrugation, and each with 10 different size dimensions were simulated. Among all of these simulations, six of them, each with two replicates were subjected to experimental tests. Experimental examples are aluminum cylindrical thin-walled tubes with the same thickness, height, and diameter that corrugations with different geometries are applied to them by the use of the cold rolling method. Finally, to describe the findings in more theoretical terms, a comparison between our obtained results and earlier theoretical investigations is made. The results show a significant influence of corrugations application on the improvement of the collapse characteristics of the cylindrical tubes so that the collapse style of intact tubes can be controlled by applying corrugations. The results show that by increasing the amplitude and number of corrugations, the absorbed energy, and the initial maximum force decrease. It is also found that among the different corrugation geometries, the corrugations with singly isosceles triangular geometry have the highest energy absorption as well as the lowest initial maximum force.

Numerical and experimental study of natural convection heat transfer on flat and corrugated plates

PurposeThe purpose of this study is to numerically and experimentally investigate the natural convection heat transfer in flat plates and plates with square, trapezoidal and triangular corrugations.Design/methodology/approachThis work is an extension of the previous studies by Verderio et al. (2021a, 2021b, 2021c, 2021d, 2022a). An experimental apparatus was built to measure the plates’ temperatures during the natural convection cooling process. Several physical parameters were evaluated through the experimental methodology. Free and open-source computational tools were used to simulate the experimental conditions and to quantitatively and qualitatively evaluate the thermal plume characteristics over the plates.FindingsThe numerical results were experimentally validated with reasonable accuracy in the range of studied for the different plates. Empirical correlations of , and , with good accuracy and statistical representativeness, were obtained for the studied geometries. The convective thermal efficiency of corrugated plates (Δη), as a function of , was also experimentally studied quantitatively. In agreement with the findings of Oosthuizen and Garrett (2001), the experimental and numerical results proved that the increase in the heat exchange area of the corrugations has a greater influence on the convective exchange and the thermal efficiency than the disturbances caused in the flow (which reduce ). The plate with trapezoidal corrugations presented the highest convective thermal efficiency, followed by the plates with square and triangular corrugations. It was also proved that the thermal efficiency of corrugated plates increases with .Practical implicationsThe results demonstrate that corrugated surfaces have greater thermal efficiency than flat plates in heating and/or cooling systems by natural convection. This way, corrugated plates can reduce the dependence on auxiliary forced convection systems, with application in technological areas and Industry 4.0.Originality/valueThe empirical correlations obtained for the corrected Nusselt number and thermal efficiency for the corrugated plate geometries studied are original and unpublished, as well as the experimental validation of the developed three-dimensional numerical code.

Impact of dimensions and optimized dimensions of corrugation of solar air heater for an indirect solar dryer for better heat transfer

Triangular corrugations were used on the absorber surface of the solar air heater (SAH) of an indirect solar dryer to enhance the heat transfer between the working fluid and the plates. A computational approach was dealt with to optimize the configuration of SAH (pitch, p; height, e and corrugation angle, θ) for better thermal performance parameters such as Nusselt number (Nu), thermo-hydraulic performance parameter (THPP) and friction factor (fr). The p and e were varied and hence θ was also varied. There were 25 computer models of SAH generated and a set of simulations were run to identify the impact of p and e. The flow behaviors (velocity, temperature and turbulence parameters) were determined for different p and e. The Nu, Nu ratio, fr and fr ratio were determined for all the models. The Nu was improved from 118.4 to 174.26 % in comparison to the smooth surface when the p and e (and hence θ) were varied. The highest THPP was observed as 1.878 at p = 130 mm, e = 10 mm and θ = 20°. This result is an innovative outcome for SAH industries.

Numerical study on the strength enhancement of circular castellated steel beams with triangular corrugations and casing assembly

Modern buildings utilize steel-castellated beams to support extensions and reduce dead weight. However, the presence of castellations weakens the structure and creates additional failure mechanisms. Corrugations and castellations were combined in this study to strengthen the web. Using the ABAQUS software, a circular castellated-triangular corrugated steel beam with a perforated casing was modeled and analyzed. Triangular corrugations with corrugation angles of 30° and 45° and circular castellations with S/D ratios of 0, 1.1, 1.5 and 2 were used. The beam sections had a span of 2000 mm, depth of 300 mm, flange width of 150 mm, flange thickness of 16 mm and web thickness of 5 mm. The ultimate load of the beam assembly was determined using GMNIA on a simply supported beam with mid-point loading. A study on a flat web beam with the same dimensions and S/D ratios was conducted to understand and compare the behavior of the new corrugated–castellated assembly with and without casing. 22 configurations in the proposed castellated-corrugated assemblage, including a plain web, were modeled and analyzed. The results show that, compared with castellations in plain web beams, more than 60% of the load-carrying capacity was observed on a 30° corrugated-castellated beam with a casing assembly. In addition, the mass-to-capacity ratio of the same beam was higher.

Corrugation geometry effect on jet mixing

An experimental investigation was carried out to assess the mixing promoting efficiency of rectangular, semicircular, and triangular corrugations at the edges of rectangular tabs. Mixing promoting capability of two rectangular tabs with aspect ratio of 1.0, 1.5, and 2.0, with rectangular, semicircular, and triangular corrugations over their edges, located diametrically opposite at the exit of a convergent–divergent Mach 1.73 nozzle was studied. Pressure measurements and optical flow visualization were carried out. The nozzle pressure ratios (NPRs) studied were 4, 5, 6, 7 and 8, in order to cover different levels of expansion at the nozzle exit. At NPR 4, Mach 1.73 nozzle is overexpanded, with about 23% adverse pressure gradient. At NPR 5, the adverse pressure gradient is just 3%. At NPR 6, 7, and 8, the jet is underexpanded with favorable pressure gradients of 16%, 36%, and 55%, respectively. The corrugated tabs were found to be efficient mixing promoters, leading to shorter core and weaker shocks in the core than the uncontrolled jet. The mixing effectiveness of the corrugated tab is found to increase with increase in NPR. The core length reduction associated with all the corrugations is found to increase with increase in tab aspect ratio. At the almost correctly expanded state, for aspect ratio 1, rectangular corrugation is found to be the most efficient mixing promoter, causing a core length reduction of almost 100%, followed by the triangular and semicircular corrugations, leading to a 77% and 73% reduction, respectively. For aspect ratios 1.5 and 2.0, triangular corrugation is found to be the most efficient mixing promoter, causing a core length reduction of almost 100%, followed by the rectangular and semicircular corrugations. The shadowgraph images of the controlled and uncontrolled jets demonstrate the effectiveness of the corrugated tabs in weakening the waves in the jet core.

Insert Misalignment Studies of a Coaxial-Cavity Gyrotron—Full-Wave Approach

Insert misalignment studies are carried out for a coaxial-cavity gyrotron with triangular corrugations on the insert wall using the full-wave approach, space harmonics method (SHM). By applying electromagnetic boundary conditions, dispersion relation is derived for a coaxial-cavity with misaligned insert. Misalignment of the insert caused by axial displacement as well as tilting of the insert axis from the outer resonator axis are taken into consideration in the study. As the electromagnetic fields in the interaction space vary with the insert misalignment, due to this the mathematical formulations of the beam-coupling coefficient, wall losses, RF interaction efficiency, and output power are modified. For a 2-MW, 220-GHz gyrotron, the insert misalignment studies are carried out using the proposed full-wave model with the help of our in-house code Gyrotron Design Suite. For validation, the results obtained using the SHM approach are compared with that of the surface impedance model (SIM) approach. In addition, comparison studies between SIM and SHM approaches are performed for the practically developed 170-GHz, 2-MW coaxial-cavity gyrotron with both triangular and rectangular corrugations in the insert.

The Effect of Shear Span on the Behavior of Triangularly Corrugated Web Steel Girders

Built-up steel girders have many applications in structural engineering, both in bridges and buildings. Flat web steel girders, which are the traditional choice, involve several weaknesses. Girders with corrugated webs were found to be more effective in their load-carrying capacity and deflection than girders with flat webs. In light of this, an effort is made in this work to examine how the addition of triangular corrugated webs influences the load-bearing capacity and deflection of steel girders. This study aimed to determine whether or not the strength of built-up steel with corrugated webs could be improved. A concentrated midspan load was applied to six simply supported steel beams of varying span-to-depth ratios (1.0, 1.833, and 2.5) and web corrugation amplitudes (30 and 60 mm). An increase in ultimate strength of 15.7% to 35.1% was found for webs with triangular corrugations of 30 mm and from 2% to 29.1% for webs with corrugations of 60 mm. A reduction in deflection of up to 35.3% can be attained when using triangular corrugated webs. It was also found that using webs with 30 mm corrugations was more efficient than using webs with 60 mm corrugations. The effect of corrugation was found to fade when the span-to-depth ratio increased to 2.5. This led to the conclusion that using webs of 30 mm amplitude of triangular corrugation could improve the strength and serviceability of steel girders. Doi: 10.28991/CEJ-2023-09-02-09 Full Text: PDF

Mixing of Fluid Phase in Layers of Regular Packing Made of Mesh with Triangular Corrugations

Mixing of Fluid Phase in Layers of Regular Packing Made of Mesh with Triangular Corrugations

Slow light generation by using one-dimensional photonic crystals for quantum memory applications

In this study, an efficient and compact optical device for slowing light in corrugated photonic crystals with different corrugation patterns are discussed. The proposed structure shows relatively large group delay with wide bandwidth and approximately zero group velocity dispersion in near-infrared region. Also, due to the zero group velocity dispersion applied on transmitted pulse, high quality pulse can be obtained by using this approach. For comparison, three different photonic crystal structures containing triangular, sinusoidal and graded sinusoidal corrugation patterns were investigated. The group index as much as 5 with the bandwidth about 50 nm is achieved in the sinusoidal corrugated photonic crystal with 8 μm length. This slow-light structure is very promising for application in quantum memories.

Heat Transfer and Flow of a Gel Fuel in Corrugated Channels

For propulsion systems using gel fuels, reducing the gel fuel viscosity is essential for achieving better atomization and combustion. In this paper, we investigate the flow and heat transfer in a water-gel with a temperature and shear dependent viscosity. We consider several different channels, mimicking the transport of gelled fuels in propulsion systems, and we also look at corrugation, which is a way of enhancing fluid mixing and thus improving the heat transfer characteristics. The rheological parameters in the constitutive model of the gel are fitted with experimental data. The influence of different corrugation profiles, corrugation configuration parameters and the Reynolds number on the mean apparent viscosity and the pressure drop are investigated. It was found that the flow recirculation formed in the valley of the corrugations enhances the heat transfer and thus the temperature of the main flow. We also noticed an increase in the pressure drop due to the stronger viscous dissipation. Furthermore, it was observed that the sinusoidal corrugation can achieve lower viscosity with a lower pressure drop compared with triangular and trapezoidal corrugations. A shorter wavelength and a deeper wave amplitude of the corrugation seemed to be better for reducing the gel fuel viscosity, while we must consider the adverse consequence of increased pressure drop. A larger Reynolds number was helpful for both lowering the pressure drop and for reducing the viscosity. In addition, compared with a smooth straight pipe, a Y-shape corrugated channel with a constant inlet velocity reduced the mean apparent viscosity by 70.8%, and this value increased to 72.6% by further applying a pulsed inlet velocity, which can greatly enhance the gel fuel atomization and thus improve the combustion efficiency.

Numerical solution of solar air heater with triangular corrugations for indirect solar dryer: Influence of pitch and an optimized pitch of corrugation for enhanced performance

A numerical attempt was carried out for enhancing the heat transfer phenomena of the solar air collector (SAC) by providing triangular corrugations over the SAC using the commercial software ANSYS fluent. Totally ten domains of SAC were created with different pitches (p) such as 55 (continuous corrugation), 60, 65, 70, 75, 95, 115, 135, 155 and 175 mm. The flow parameters such as velocity, temperature, turbulent kinetic energy, turbulent intensity and performance parameters such as Nusselt number (Nu), Nu ratio, friction factor (f), f ratio and thermo-hydraulic performance parameter (THPP) were estimated for both smooth and corrugated surfaces for different Reynold number (Re) of 3000 to 18000. The f and f ratio decreased continuously with Re. An increment of 199.95% in Nu was noticed at p of 55 mm and Re of 3000 compared to a smooth plate. A maximum Nu and THPP of 124.75 and 1.726, respectively, were noticed at p = 135 mm at Re = 18000 and further increase or decrease in p created low Nu and THPP and hence the optimized p was 135 mm. The numerical results were validated with previous research on a similar domain and found good agreement.

Performance Evaluation of Composite Wall with Boundary Column Having Triangular Corrugation

Abstract: Composite wall is an innovation in the field of Civil Engineering that enhances the constructability by eliminating reinforcing bars and formwork. Double skin composite wall consist of a concrete core is placed between outer steel plates. By providing corrugation in the steel plate improves the seismic behavior and also stability against buckling. This paper aims to the performance evaluation of corrugation on composite wall with boundary column. For this study, four FE models of composite wall with boundary column having triangular corrugation were analyzed using Ansys 2022 R1. Composite wall with different height of corrugation ie., 25 mm, 30 mm, 40 mm and 45 mm is evaluated under monotonic loading to understand the total deformation and equivalent stress. Also perform buckling analysis on the better model obtained from different geometry of corrugation. Study shows that model with 45 mm height of corrugation shows maximum load carrying capacity

Hydrodynamically induced helical particle drift due to patterned surfaces

Advances in microfabrication enable the tailoring of surfaces to achieve optimal sorting, mixing, and focusing of complex particulate suspensions in microfluidic devices. Corrugated surfaces have proved to be a powerful tool to manipulate particle motion for a variety of applications, yet the fundamental physical mechanism underlying the hydrodynamic coupling of the suspended particles and surface topography has remained elusive. Here, we study the hydrodynamic interactions between sedimenting spherical particles and nearby corrugated surfaces, whose corrugations are tilted with respect to gravity. Our experiments show three-dimensional, helical particle trajectories with an overall drift along the corrugations, which agree quantitatively with our analytical perturbation theory. The theoretical predictions reveal that the interaction of the disturbance flows, induced by the particle motion, with the corrugations generates locally a transverse anisotropy of the pressure field, which explains the helical dynamics and particle drift. We demonstrate that this dynamical behavior is generic for various surface shapes, including rectangular, sinusoidal, and triangular corrugations, and we identify surface characteristics that produce an optimal particle drift. Our findings reveal a universal feature inherent to particle transport near patterned surfaces and provide fundamental insights for future microfluidic applications that aim to enhance the focusing or sorting of particulate suspensions.

Mixed Convection in a Lid‐Driven Cavity with Triangular Corrugations and Built‐in Triangular Block

The influence of triangular surface corrugations on the mixed convection characteristics in a tall lid-driven cavity for non-Newtonian power-law fluids is reported. In particular, numerical experimentations are executed for a range of parameters, such as aspect ratio of cavity, number of triangular corrugations, Richardson numbers, Prandtl numbers (Pr), power-law indexes, and at a constant Grashof number. The corrugation number seems to be the maximum impact for higher Prandtl number fluids. For taller cavities, higher Nusselt number values were obtained for Pr = 100. Triangular corrugations showed a modest change in the heat transfer augmentation in most of the considered parameters.

Thermohydraulic performance enhancement using novel hybrid corrugation configuration channels in thermal systems

High heat generation in the electronic components results in dire performance if it is not dissipated efficiently. The dissipation of heat from these components can be made efficient by adopting corrugated channels in the heat sink. The present work uses novel designs of the corrugation configurations to enhance the heat transfer rate. The considered corrugation configurations with three different shapes arc, trapezoidal, and triangular are inward-only (no outward configuration), non-hybrid (inward and outward configurations are same), and hybrid (inward and outward configurations are different). Numerical simulations are performed to analyze entropy generation, heat transfer, and fluid flow in the corrugated channels. Different uniform inlet velocities corresponding to Reynold numbers 15,000, 22,500, 30,000, and 37,500 are considered. All the corrugation configuration channels help in improving convective heat transfer as compared to the simple channel. The Nu is highest in the case of inward arc-outward triangular hybrid corrugation configuration at the highest considered Re. But at the same time, inward trapezoidal-outward triangular hybrid corrugation configuration channel results in the highest increment in the Nu as compared to the simple channel at the lowest Re and this increment is 68.46%. When all these channels are analyzed for the friction factor, inward trapezoidal-outward trapezoidal corrugation configurations result in the highest friction factor at all the flow rates. In terms of entropy generation assessment, the simple channel has the highest Sgen while the inward arc-outward triangular hybrid corrugation configuration has the least Sgen among the considered cases. The inward trapezoidal-outward triangular hybrid configuration is recommended at low Re over other configurations based on lowest Ns,a equals to 0.594.