Vertical Plate Research Articles

A Wideband Circularly Polarized Dipole Antenna with Compact Size and Low-Pass Filtering Response.

This paper presents a compact wideband circularly polarized cross-dipole antenna with a low-pass filter response. It consists of two pairs of folded cross-dipole arms printed separately on both sides of the top substrate, and the two dipole arms on the same surface are connected by an annular phase-shifting delay line to generate circular polarization. A bent metal square ring and four small metal square rings around the cross-dipoles are employed to introduce new resonant frequencies, effectively extending the impedance and axial-ratio bandwidth. Four square patches printed on the middle substrate are connected to the ground plane by the vertical metal plates in order to reduce the antenna height. Thus, a compact wideband circularly polarized antenna is realized. In addition, a transmission zero can be introduced at the upper frequency stopband by the bent metal square rings, without using extra filter circuits. For verification, the proposed model is implemented and tested. The overall size of the model is 90mm×90mm×33mm (0.37λ0×0.37λ0×0.14λ0; λ0 denotes the center operating frequency). The measured impedance bandwidth and 3 dB axial-ratio (AR) bandwidth are 53.3% and 41%, respectively. An upper-band radiation suppression level greater than 15 dB is realized, indicating a good low-pass filter response.

Analytical calculation method of circular-section rocking steel piers under horizontal cyclic load

The research object of this paper is to investigate the mechanical behavior and develop an analytical model of the prestressed circular-section rocking steel piers with external energy-dissipating devices under the horizontal cyclic load. Based on the method of monolithic beam analogy under monotonic loading, the concept of generalized rotation angle and intercept strain in the pre-decompression state was introduced. The geometrical equations for the pre- and post-decompression stages are deduced. The calculation formulas for internal forces of each component and the analytical calculation method for the entire process of the rocking steel pier under horizontal cyclic loading are established in detail. To reproduce the hysteresis curve of the test, some special test conditions, such as the retraction effect of prestressed tendons and increase of the compressed area due to the vertical plates, were considered in the analytical model. The results show that the analytical method based on generalized rotation angle and intercept strain can ensure an ideal transition of the hysteresis curve of the pier in pre- and post-decompression stages. Except for the pier with particularly severe local buckling and ovalization deformation, the calculated results obtained from the proposed analytical model agrees well with the test results for the rocking steel bridge piers. The effect of prestressed tendons and the P–Δ effect on the lateral load–displacement curve of rocking steel bridge biers was further analyzed through parametric study using the proposed model. The analytical calculation method presented in this paper provides a theoretical tool for seismic design of the rocking steel pier in engineering practice. This paper provides important guidance for the establishment of seismic design method of rocking steel piers.

Influences of thermal stratification and chemical reaction on MHD free convective flow along an accelerated vertical plate with variable temperature and exponential mass diffusion in a porous medium

AbstractThis study examines the impacts of thermal stratification and chemical reaction on magnetohydrodynamic (MHD) free convective flow along an accelerated vertical plate with variable temperature and exponential mass diffusion, set within a porous medium. Analytical solutions, utilized, are obtained through the Laplace transform technique to accurately represent the flow's physical mechanism. The research employs advanced mathematical models to analyze the intricate interplay between MHD and convective processes under varying thermal and exponential mass diffusion conditions, offering insights into fluid dynamics that closely simulate real‐world conditions. The study draws a significant conclusion by contrasting the effects of thermal stratification with a nonstratified environment. It has been noted that when stratification is applied to the flow, the steady state is achieved more quickly. The study reveals that thermal stratification reduces fluid velocity and temperature but increases skin friction and the Nusselt number, diverging from nonstratified conditions. It also shows that parameters, like, , and significantly influence velocity, temperature, and concentration in fluid dynamics. This research could be driven by a need to enhance the understanding of fluid flow in various engineering and environmental contexts, where such conditions are prevalent, including geothermal energy extraction, thermal management, chemical processing industries, and environmental control technologies. This novel approach enhances understanding of flow processes in both natural and engineered porous environments.

Soret and Dofour effects on unsteady MHD convection flow over an infinite vertical porous plate

In this paper, the computational examination is carried out on the heat generation, Soret and Dufour’s influence on the unsteady MHD convection flow of an incompressible viscous fluid with chemical reaction. It is due to the exponentially accelerated vertical porous plate embedded in a permeable medium with ramped wall temperature together with surface concentration and also with thermal radiation impacts. The basic governing set of the equations of the fluid dynamics to the flow is converted into nondimensional form by inserting suitable nondimensional parameters and variables. In addition, the resultant equations are solved computationally with the efficient Crank–Nicolsons implicit finite difference methodology. The influences for several imperative substantial parameters for the model on the velocity, temperature and concentration for the fluids, the skin friction coefficient, Nusselt and Sherwood number for together thermal situations have been explored with the help of graphical profiles and tabular forms. It is found that, the increasing quantities of the Dufour, temperature generation and thermal radiation parameters, the fluid temperature as well as velocity enhances. Similarly, it is noted that an escalating Soret parameter causes the fluid’s velocity and concentration whereas the chemical reaction parameter notifies reversal outputs.

Semi-analytical approach to study wave interaction with a pair of obliquely submerged heterogeneous flexible structures

ABSTRACT Analyzing inclined flexible plates of varying thickness is crucial for optimising and attaining precise control over wave reflection and transmission. This is particularly significant in the context of breakwater construction. In contrast to horizontal breakwaters, inclined barriers can penetrate multiple layers of fluid with varying particle velocities, facilitating interactions and causing wave breaking, which results in the dissipation of wave energy. Moreover, compared to vertical structures, inclined ones demonstrate more effective wave attenuation. In the context of the present study, we investigate the interaction of water waves with a pair of obliquely submerged flexible thin plates characterised by non-uniform thickness. In order to model this complex physical scenario, we employ the principles of linear water wave theory in conjunction with Kirchhoff's thin plate theory. By employing repeated integration and Green's integral theorem, we reduce the boundary value problem to a system of coupled integral equations. Through appropriate approximations, we solve this system and obtain numerical values for various hydrodynamic quantities. This model provides comprehensive results for both horizontal and vertical plates, making it highly versatile. We examine the impact of varying thickness and the inclination of the two flexible plates to understand their roles in the wave scattering process and the associated physical parameters. The results obtained from this study shed light on the intricate dynamics involved in wave-structure interactions and can inform the design and optimisation of breakwater systems.

Computational workflow to monitor the electroosmosis of nanofluidic flow in the vicinity of a bounding surface

This investigation studies the flow of a boundary layer with electroosmotic forces on a nanofluid with gyrotactic microorganisms along the vertical Riga plate. This sort of fluid movement necessitates specific mathematical techniques and numerical simulations. In addition, the boundary-layer flow is induced by the mass and heat transfer, Joule heating, and viscous dissipation. A mathematical model is simulated by non-linear partial differential equations (PDEs). The combination of PDEs is turned into a set of non-linear ordinary differential equations using proper transformations. Some analysis tools are used to investigate the morphological characteristics of the problem while applying suitable boundary conditions. The influence of parameters on the derived solutions is numerically and visually explained through sets of figures. It is elucidated that the concentration of the microorganisms reduces due to an increase in Lewis number which leads to a decrease in the motile microorganism’s density profile. It is seen that the temperature distribution is improved when the chemical reaction and Casson parameter increase. In addition, we find that the application of electro-osmotic forces applied to the surfaces helps to dewater and separate microorganisms from incompressible solid and liquid mixtures.

Vibration responses of vertical coupling plates considering elastic boundary and flexible joint connection using traveling wave approach

Complex structures are usually assembled by basic structure components, such as beams, plates, with different boundaries. It is necessary to study the vibration responses of coupling structures considering the connection effects between plates, which is the basis for structural vibration suppression and high-precision control of complex structures. In this work, the vibration responses of vertical coupling finite-length plates considering elastic boundary and flexible joint connection are investigated using numerical methodology. First, the theoretical model of the vertical coupling plates is established using the traveling wave method, in which the plate boundary is considered as elastic support, and the connection between vertical coupling plates is considered as flexible connection joint. The mathematical model of flexible connection between vertical coupling plates as well as the elastic boundary is introduced by using equivalent spring-damper model. Then, the influence of boundary conditions, connection conditions and excitation on the vibration responses are investigated by different case studies. The numerical simulation results indicate that boundary conditions, connection conditions and excitation have significant effects on the vibration responses of the vertical coupling plates. This investigation provides a theoretical basis for vibration response predication and vibration suppression and high-precision control of complex structures, which plays important theoretical significance and engineering application prospect.

Convective heat loss from a modified solar cavity receiver with vertical plate fins: An experimental assessment

AbstractExperimental investigations have been conducted to study the convective heat transfer from a cylindrical solar cavity receiver with vertical fins. The experiments were performed under varying surface heat flux levels and at seven inclination angles, ranging from −90° (upward facing) to +90° (downward facing) at 30° intervals. The impact of fins on the heat transfer process was studied by conducting experiments in two scenarios, namely, finned and unfinned cavities. The findings of the study showed that with an increase in cavity inclination, the magnitude of convective heat loss decreased in both finned and unfinned cavities, while the cavity surface temperature increased. At +90° inclination, the convective heat loss and Nusselt number were observed to have the lowest value, while the surface temperature had the highest value. For a downward‐facing cavity, the fins reduced convective heat loss, leading to an increase in cavity surface temperature. The finned cavity performed better for a vertically downward‐facing inclination (+90°) as it had a contribution of only 11% for convection heat loss compared with the unfinned cavity, which had a contribution of 21% for the same. Furthermore, an empirical model was developed based on the experimental results for the Nusselt number, which correlates experimental data with an error margin of ±15%. This model can be used to predict the Nusselt number for different inclination angles and surface heat flux levels. The presence of vertical fins in the cavity was found to be effective in reducing convective heat loss, especially for downward‐facing cavities. Understanding the influence of fin and cavity inclination on convective heat transfer can lead to enhanced efficiency and performance of solar receivers, thereby increasing the overall energy output of the system.

Analytical investigation of heat and mass transfer in MHD nano fluid flow past a moving vertical plate

This study aims to derive analytical expressions for temperature, concentration, and velocity in an unsteady MHD convective nanofluid flow past a moving vertical plate. The governing nonlinear differential equations are solved analytically using the Homotopy Analysis Method (HAM). The resulting solutions are presented as concentration, temperature, and velocity profiles, allowing for the analysis of various physical parameters' influence on the flow behavior. Furthermore, our analytical results are validated by comparing them with existing numerical solutions using MATLAB. The impact of these parameters on skin friction, the Nusselt number, and the Sherwood number is presented, demonstrating good agreement with previously reported data. The findings of this research hold significance for industries involving heat transfer processes, such as thermal management systems, electronic cooling, and energy generation applications.

Application of fractional derivative on nanofluid with magnetic field

The study investigates the combined impact of heat and mass transfer on a vertical plate, considering factors such as an applied magnetic field, thermal radiation, heat absorption, and a first-order chemical reaction. The fluid under examination is assumed to be an electrically conducting Cu-nanofluid based on water. Thermophysical properties are derived from Table 1 for both the base fluid (water) and nanoparticles (Cu), with the nanoparticle volume fraction chosen within the range of 0.01 to 0.02. A novel aspect of this study involves considering both passive and active control of the Maxwell nanofluid. The governing equations are solved using the Laplace transform technique to obtain uniform closed-form solutions. Graphical representations illustrate the velocity, temperature, concentration, and Bio-Convection profiles under various flow parameters. Remarkably, the velocity profile exhibits consistent behavior for both stationary η = 0 and moving η = 1 plates, as depicted in Figures 2–10. The obtained semi-analytical solutions successfully fulfill all initial and boundary conditions. Moreover, manipulating the nanoparticle volume fraction demonstrates significant control over the flow and heat transfer characteristics.

On the natural transition of the natural convection boundary layer under a constant heat flux condition

This study investigates the thermo-fluidic characteristics of a natural convection boundary layer over a vertical plate heated under a constant heat flux condition. We used particle image velocimetry to observe the surface convection velocity at the proximity of the plate, which is submerged in a water chamber with Rayleigh number, Ra=7×109 and Prandtl number, Pr = 8.1. The velocity distributions indicated the presence of distinct stripe-like flow structures in the early transition (upstream) region and that of distinct negative–positive Λ-shaped flow structures in the downstream region. In addition, the temporal variation of spanwise and streamwise velocity components was presented. Furthermore, proper orthogonal decomposition (POD) analysis was used to reduce the complexity of the flow structure and retain the most salient characteristics of the flow field. Our results confirmed the existence of a very weak inceptive oscillation in the behaviour of POD time coefficients in the upstream region.

Mechanical and microstructural characterization of AISI SAE 4130 steel welded joints made by robotic gas metal arc welding process: influence of electrode work angle in 'T' welded joints

Microstructural variations within welded metals, specifically in terms of phases and their corresponding volume fractions, play a crucial role in influencing weld strength and other mechanical properties. Welded joints in a ‘T’ configuration pose a unique challenge due to the dynamic heat distribution caused by changes in the electrode work angle (EWA) between perpendicularly aligned plates. This study focuses on characterizing the microstructure and micro-hardness of ‘T’ welded joints in a 6 mm thick plate of AISI SAE 4130, welded using the robotic gas metal arc welding process. The examination covers three distinct zones: the base material (BM), the fusion zone (FZ), and the heat-affected zone (HAZ). The extent of the HAZ is meticulously measured on both the vertical and horizontal plates within the weld zones. The x-ray diffraction (XRD) analysis results indicated that the average crystallite size of the base metal and fusion zone is 25.75 nm and 24.51 nm respectively. As per the scanning electron microscope (SEM) image observations, the higher wire feed rate yields to brittle fracture surface. The torch angles notably influence the dimensions of the HAZ on the vertical and horizontal plates of a ‘T’-Joint. Welding at higher EWA and contact-tip-work-distance, results in a larger HAZ on the vertical plate. Conversely, employing a flattened EWA and an increased contact-tip-work-distance leads to a greater extent of the HAZ on the horizontal plate. Furthermore, the micro-hardness of the fusion zone and heat-affected zone demonstrates an increase at higher settings of wire feed rate and travel speed. This phenomenon is attributed to the elevated heat inputs, which contribute to the formation of a finer microstructure within the weldment.

Cyclic behavior of the reinforced concrete shear walls with opening retrofitted with steel plate

AbstractThe reinforced concrete (RC) shear walls are widely used as the lateral load‐resisting system due to their adequate ductility and great energy dissipation capacity. On the other hand, use of these walls can reduce the size of the beams and columns and also, decreases the lateral displacements. However, presence of the openings in the shear walls alters the behavior of the wall and therefore, the dimensions and position of the opening play a key role in the performance of this structural system. In this study, an RC shear wall with eccentric opening was verified using ABAQUS software. This model, which is called the reference model, a wall and a pier have been created according to aspect ratios given by ACI318‐14. This model was retrofitted with the steel plates arranged in various patterns and effect of each pattern on the system's performance was investigated and the best one was selected. The best steel plate arrangement increased the ultimate strength, maximum strength, cracking strength, and energy dissipation capacity by 127.3%, 13.42%, 22.53%, and 16.8%, respectively. To practically use this retrofit technique, three low, mid, and high‐rise buildings designed based on the old and new versions of the Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard 2800) were upgraded with this technique and their performance was evaluated and performance of the substandard and standard buildings were compared with each other. The research results showed the ST52 steel plates do not considerably increase the maximum and cracking strength and could enhance the ultimate strength insignificantly. By retrofitting the edges of the openings by the diagonal steel plates and preventing spread of the cracks at the edges and corners, satisfactory results could be attained. Simultaneous use of the vertical and horizontal plates is an effective solution to increase the flexural and shear capacity of the structure.

Convective heat and mass transfer in inclined parallel plates with fractional model: Dusty hybrid nanofluid

AbstractThis paper investigates the flow of a second‐grade viscoelastic fluid with dust particles under hydromagnetic effects between vertical plates. This study investigates the effects of the left plate's oscillations, which induce fluid motion, on heat and mass transfer, and particle temperature. The study also considers the variable temperature and concentration. Mathematical models are developed using partial differential equations to represent the flow regime. To generalize energy and concentration Fick's and Fourier's laws are employed. Laplace and finite Fourier‐Sine transforms are then used to solve the resulting system of dimensionless equations. Finally, Zakian's numerical technique is used in MATHCAD software to compute the Laplace inverse and obtain the final solution. The research concludes that the fractional approach is more realistic and practical than the classical approach. Changes in mass and heat transfer rates, as well as skin friction on the left plate, are observed over time across various physical parameters. Additionally, dust particles can be employed in various applications, including agriculture. In this sector, they can be mixed with water to create a dust suspension, which is subsequently sprayed over crops to enhance the effectiveness of pesticide application.

MHD Casson ternary hybrid nanofluid flow through a vertical porous plate with thermal radiation: A finite difference approach

AbstractThis entire study aims to investigate the impacts of linear thermal radiation and MHD Casson ternary hybrid nanofluid flows over a vertical porous plate for comparison of nanofluid, hybrid, and tri‐hybrid nanofluids with Newtonian and non‐Newtonian fluids. We used a ternary hybrid nanofluid, Blood contains three types of oxides and metals: spherical ferric oxide (Fe3O4), platelet‐shaped zinc (Zn), and cylindrically‐shaped gold (Au) nanoparticles. The coupled nonlinear dual partial differential equations (PDEs) are turned into PDEs using nondimensional quantities. The Finite Difference Method (FDM) and the Perturbation Method are then used to solve the PDEs. The impacts of different parameters on temperature, velocity, Nusselt number, and Skin friction profiles have been discussed. The increase in viscosity occurs because an increase in Gr also causes an increase in the velocity field for nanofluid, hybrid, and tri‐hybrid nanofluids. A tri‐hybrid nanofluids performs better among the three, such as nanofluid, hybrids and tri‐hybrid nanofluids. As the volume fractions (Fe3O4) increase, the temperature increase for both Newtonian and non‐Newtonian fluids. The increase in temperature is due to the thermal conductivity of nanoparticles, which is enhanced by growth estimates of the nanoparticle volume fraction. The high temperature of the fluid is observed for large estimates of nanoparticle volume fraction. An increase gold (Au) also increases the temperature for shapes (cylinder, platelet, and spherical). A spherical shape performs better among the three, such as cylinder, platelet, and spherical. In this model, biomedical applications such as antiviral and therapeutic, treatment of the COVID‐19 virus, cancer treatment, and anticancer medication delivery systems.

Modeling heat and mass transfer in granular flows between vertical parallel plates

Gravity-driven granular flows between vertical parallel plates at elevated temperatures are integral in the development of the next generation of particle-based heat exchangers for concentrated solar power. Efficient modeling methodologies that accurately captures the heat transfer mechanisms of temperature-dependent granular flows are essential to effectively design and evaluate these heat exchangers. Transient, pseudo-one-dimensional heat and mass transfer models were developed for inlet flow temperatures between 473 and 1073 K. The mass transfer models for the granular flows were resolved using discrete element method simulation, providing detailed temporal and spatial distributions of flow parameters in good agreement with experimental measurements. The heat transfer model employed a one-dimensional, two-phase, continuum approach, and a system of non-linear differential equations was solved via finite difference method. The particle-to-wall contact heat transfer was determined with an effective thermal conductance model. Radiative heat transfer between particles and walls was also considered. The predicted particle and wall temperatures for two different channel widths of 6.4 and 2 mm were well-correlated to previously obtained experimental measurements with Pearson’s correlation coefficients greater than 0.91. A significant disparity in particle temperature of up to 72 K was observed when radiative heat transfer was omitted, and a maximum temperature difference of 11 K was observed when temperature-dependent granular flow properties were not considered. The model revealed that radiative heat transfer potentially contributed to > 30 % of heat losses in wider channels at high inlet temperatures, and conduction was the dominated heat transfer mechanisms in narrower channels (∼70 %) due to increased particle-to-wall contact. This accurate model, leveraging discrete element method in a streamlined approach, advances the understanding and modeling of heat transfer in granular flows at elevated temperatures, enabling more efficient and reliable solar thermal energy storage and transport.

Solar radiation and heat sink impact on fluctuating mixed convective flow and heat rate of Darcian nanofluid: Applications in electronic cooling systems

One of the most effective techniques for electronic-cooling devices involves the use of nanofluid, a substance known for its superior heat transfer capabilities. The main challenge in modern production engineering lies in the efficient cooling of electronic devices. Nanofluids have attracted widespread interest in various technical fields due to their exceptional characteristics, which enable effective cooling of electronic devices while improving energy efficiency. In the field of electronic systems, engineers are exploring the potential of nanofluids in a range of applications and phenomena. Choosing the right heat transfer fluid to dissipate heat is crucial in managing electronic component temperatures. This study examines the effects of heat sinks and thermal radiation on the flow of Darcy-Forchheimer nanofluid over a vertical plate, with the aim of enhancing the thermal durability of electronic components. The governing mathematical model has been refined to accurately represent the physical coefficients. To develop a relevant algorithm in the FORTRAN environment, primitive variables are employed in steady-state and oscillatory models, nanomaterial and heat sink. Outputs are presented numerically and graphically using Tecplot 360, revealing that an increase in heat sink capacity leads to a reduction in surface temperature due to the heat sink's ability to absorb excess thermal energy. The use of porous Darcy-Forchheimer material is shown to lower the fluid temperature. The study also shows that the heat transfer rate decreases with an increase in the heat sink coefficient, and the oscillatory frequency of heat transfer reduces with a decrease in the Prandtl number. Decreasing behavior of heat transfer is depicted for maximum thermophoretic factor due to heat sink impact.

Limiting behaviours of unsteady mixed convection flow past a vertical flat plate in a porous medium

The study of the limiting behaviours of a mathematical model is crucial for understanding the stability of the model, gaining insight into asymptotic properties, predicting the long-term behaviour of system as well as validating the model. However, most of the research studies focus on numerical solutions but overlook the asymptotic solutions. In this paper, the limiting behaviours of unsteady mixed convection over a vertical flat plate in a porous medium is studied. The transformed similarity ordinary differential equations are solved both numerically and asymptotically for an unsteadiness parameter and a mixed convection parameter. It is found that the existence of critical value of mixed convection parameter for decelerating flow results in the two branches of possible solutions. For large values of the mixed convection parameter, the results for asymptotic solution agreed well with the numerical solutions especially for accelerating flow.

Effect of vertical stiffeners on the seismic performance of T‐shaped CFST column to steel beam joint

SummarySpecial‐shaped concrete‐filled steel tubular (SCFST) columns have recently been developed for efficient steel‐concrete composite construction. In this study, a novel vertical stiffener joint for the SCFST column and steel beam frame structure is proposed. Five SCFST columns with H‐section beam joints were investigated under cycling loading. The test parameters mainly consider the column stiffening form, vertical stiffener type, and the column axial load. The failure pattern, hysteretic curves, and strain development of specimens are analyzed. Experimental results demonstrate the proposed joint with vertical stiffeners can develop the steel beam's full plastic flexural capacity and exhibit favorable seismic performance. In addition, a finite element (FE) model is developed to explore the effects of the following parameters on the hysteretic performance: vertical stiffener sizes, width‐to‐thickness ratio of column steel tube, and the column axial load. Based on the experimental and FE analyses, a stress and deformation model of the joint steel tube was established. To facilitate the practical applications, a calculation formula for joint strength was also put forward, considering the contribution of vertical stiffener, and front and side steel plates of the joint steel tube.

Моделирование турбулентной естественной конвекции на основе 2-жидкостного подхода

The paper provides mathematical modeling of turbulent natural air convection at a heated vertical plate based on a fairly recently developed two-liquid turbulence model. The considered problem, despite its relative simplicity, contains all the main elements characteristic of the currents near the wall due to buoyancy forces. A significant disadvantage of the RANS turbulence models used to solve such problems is that for their numerical implementation it is necessary to set the laminar-to-turbulent transition point, which must be determined experimentally. Thus, all RANS models are unable to describe a laminar-to-turbulent transition zone. Therefore, the main purpose of the work is to test the ability of the two-liquid turbulence model to describe the transition zone. Well-known publications have shown that the two-liquid model has high accuracy and stability, and is also able to adequately describe anisotropic turbulence. The turbulence model used in this work is supplemented with an additional thermal force, which can be ignored in many flows with forced convection. However, in the natural convection currents, it is this force that contributes to the transition of the flow regime. To validate the model, as well as to verify the computational procedure, the numerical results obtained are compared with the results of the well-known RANS turbulence models (the one-parameter Spalart-Allmaras (SA) model and the Reynolds stress transfer (RSM) model), as well as with the available experimental data. It is shown that the two-liquid model adequately reproduces the laminar-to-turbulent transition zone, and the numerical results obtained are in good agreement with experimental data.