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1 – 9 of 9Vipin Gupta, Barak M.S. and Soumik Das
This paper addresses a significant research gap in the study of Rayleigh surface wave propagation within a piezoelectric medium characterized by piezoelectric properties, thermal…
Abstract
Purpose
This paper addresses a significant research gap in the study of Rayleigh surface wave propagation within a piezoelectric medium characterized by piezoelectric properties, thermal effects and voids. Previous research has often overlooked the crucial aspects related to voids. This study aims to provide analytical solutions for Rayleigh waves propagating through a medium consisting of a nonlocal piezo-thermo-elastic material with voids under the Moore–Gibson–Thompson thermo-elasticity theory with memory dependencies.
Design/methodology/approach
The analytical solutions are derived using a wave-mode method, and roots are computed from the characteristic equation using the Durand–Kerner method. These roots are then filtered based on the decay condition of surface waves. The analysis pertains to a medium subjected to stress-free and isothermal boundary conditions.
Findings
Computational simulations are performed to determine the attenuation coefficient and phase velocity of Rayleigh waves. This investigation goes beyond mere calculations and examines particle motion to gain deeper insights into Rayleigh wave propagation. Furthermore, this investigates how kernel function and nonlocal parameters influence these wave phenomena.
Research limitations/implications
The results of this study reveal several unique cases that significantly contribute to the understanding of Rayleigh wave propagation within this intricate material system, particularly in the presence of voids.
Practical implications
This investigation provides valuable insights into the synergistic dynamics among piezoelectric constituents, void structures and Rayleigh wave propagation, enabling advancements in sensor technology, augmented energy harvesting methodologies and pioneering seismic monitoring approaches.
Originality/value
This study formulates a novel governing equation for a nonlocal piezo-thermo-elastic medium with voids, highlighting the significance of Rayleigh waves and investigating the impact of memory.
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This study aims to examine the impacts of higher memory dependencies on a novel semiconductor material that exhibits generalized photo-piezo-thermo-elastic properties…
Abstract
Purpose
This study aims to examine the impacts of higher memory dependencies on a novel semiconductor material that exhibits generalized photo-piezo-thermo-elastic properties. Specifically, the research focuses on analyzing the behavior of the semiconductor under three distinct temperature models.
Design/methodology/approach
The study assumes a homogeneous and orthotropic piezo-semiconductor medium during photo-thermal excitation. The field equations have been devised to encompass higher order parameters, temporal delays and a specifically tailored kernel function to address the problem. The eigenmode technique is used to solve these equations and derive analytical expressions.
Findings
The research presents graphical representations of the physical field distribution across different temperatures, higher order plasma heat conduction models and time. The results reveal that the amplitude of the distribution profile is markedly affected by factors such as the memory effect, time, conductive temperature and spatial coordinates. These factors cannot be overlooked in the analysis and design of the semiconductor.
Research limitations/implications
Specific cases are also discussed in detail, offering the potential to advance the creation of precise models and facilitate future simulations.
Practical implications
The research offers valuable information on the physical field distribution across various temperatures, allowing engineers and designers to optimize the design of semiconductor devices. Understanding the impact of memory effect, time, conductive temperature and spatial coordinates enables device performance and efficiency improvement.
Originality/value
This manuscript is the result of the joint efforts of the authors, who independently initiated and contributed equally to this study.
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Anand Kumar Yadav, M.S. Barak and Vipin Gupta
This paper aims to study the impact of pyro-electricity, moisture and temperature diffusivity on the energy distribution of plane waves at the free surface of an orthotropic…
Abstract
Purpose
This paper aims to study the impact of pyro-electricity, moisture and temperature diffusivity on the energy distribution of plane waves at the free surface of an orthotropic piezo-hygro-thermo-elastic medium.
Design/methodology/approach
This study presents the novel creation of governing equations for an anisotropic piezothermoelastic medium with moisture impact, which is a significant contribution of this paper.
Findings
In addition to providing numerical data for the amplitude ratios and energy ratios of reflected waves, this study identifies five different kinds of coupled reflected plane waves, namely, quasi-longitudinal P wave, quasi-thermal wave, quasi-transverse wave, quasi-moisture wave and electric potential wave.
Research limitations/implications
The graphical analysis examines the impact of various factors, such as the angle of incidence, moisture and temperature diffusivity, pyro-electricity and frequency, on energy distribution.
Practical implications
This paper's results significantly impact the development of more efficient piezoelectric materials and their applications in geophysics.
Originality/value
The authors of the submitted document initiated and produced it collectively, with equal contributions from all members.
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Mallikarjun S. Bhandiwad, B.M. Dodamani and Deepak M.D.
The present work involves analytical and experimental investigation of sloshing in a two-dimensional rectangular tank including the effect of porous baffles to control and/or…
Abstract
Purpose
The present work involves analytical and experimental investigation of sloshing in a two-dimensional rectangular tank including the effect of porous baffles to control and/or reduce the wave motion in the sloshing tank. The purpose of this study is to assess the analytical solutions of the drag coefficient effect on porous baffles performance to track free surface motion variation in the sloshing tank by comparison with experimental shake table tests under a range of sway excitation.
Design/methodology/approach
The linear second-order ordinary differential equations for liquid sloshing in the rectangular tank were solved using Newmark’s beta method and obtained the analytical solutions for liquid sloshing with dual vertical porous baffles of full submergence depths in a sway-oscillated rectangular tank following the methodology similar to Warnitchai and Pinkaew (1998) and Tait (2008).
Findings
The porous baffles significantly reduce wave elevation in the varying filled levels of the tank compared to the baffle-free tank under the range of excitation frequencies. It is observed that the Reynolds number-dependent drag coefficient for porous baffles in the tank can significantly reduce the sloshing elevations and is found to be effective to achieve higher damping compared to the porosity-dependent drag coefficient for porous baffles in the sloshing tank. The analytical model’s response to free surface elevation variations in the sloshing tank was compared with the experiment’s test results. The analytical results matched with shake table test results with a quantitative difference near the first resonant frequency.
Research limitations/implications
The scope of the study is limited to porous baffles performance under range sway motion and three different filling levels in the tank. The porous baffle performance includes Reynolds number dependent drag coefficient to explore the damping effect in the sloshing tank.
Originality/value
The porous baffles with low-level porosities in the sloshing tank have many engineering applications where the first resonant mode of sloshing in the tank is more important. The porous baffle drag coefficient is an important parameter to study the baffle’s damping effect in sloshing tanks. Hence, obtained analytical solution for liquid sloshing in the rectangular tank with Reynolds number as well as porosity-dependent drag coefficient (model 1) and porosity-dependent drag coefficient porous baffles (model 2) performance is discussed. The model’s test results were validated using a series of shake table sloshing experiments for three fill levels in the tank with sway motion at various excitation frequencies covering the first four sloshing resonant modes.
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Mehdi Mohamadi and AmirMahdi Tahsini
The purpose of this study is to investigate the combustion of the n-Heptane droplets in the supersonic combustor with a cavity-based fuel injection configuration. The focus is on…
Abstract
Purpose
The purpose of this study is to investigate the combustion of the n-Heptane droplets in the supersonic combustor with a cavity-based fuel injection configuration. The focus is on the impacts of the droplet size on combustion efficiency.
Design/methodology/approach
The finite volume solver is developed to simulate the two-phase reacting turbulent compressible flow using a single step reaction mechanism as finite rate chemistry. Three different fuel injection settings are studied for the considered physical geometry and flow conditions: the gas fuel injection, small droplet liquid fuel injection and big droplet fuel. The fuel is injected as a slot wall jet from the bottom of the cavity.
Findings
The results show that using the small droplet size, the complete fuel consumption and combustion efficiency can be achieved but using the big droplet sizes, most fuel exit the combustor in the liquid phase and gasified unburned fuel. It is also demonstrated that the cavity's temperature distribution of the liquid fuel case is different from the gas fuel, and two flame branches are observed there due to the droplet evaporation and combustion in the cavity.
Originality/value
To the best of the authors’ knowledge, this study is performed for the first time on the combustion of the n-Heptane fuel droplets in scramjet configuration, which is promising propulsion system for the future economic flights.
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Yi Xie and Baojin Zheng
This paper aims to apply the novel numerical model to analyze the effect of pillar material on the response of compound quartz crystal resonator (QCR) with an array of pillars…
Abstract
Purpose
This paper aims to apply the novel numerical model to analyze the effect of pillar material on the response of compound quartz crystal resonator (QCR) with an array of pillars. The performance of the proposed device compared to conventional QCR method was also investigated.
Design/methodology/approach
A finite element method model was developed to analyze the behavior of QCR coupled with an array of pillars. The model was composed of an elastic pillar, a solution and a perfectly matched layer. The validation of the model was performed through a comparison between its predictions and previous experimental measurements. Notably, a good agreement was observed between the predicted results and the experimental data.
Findings
The effect of pillar Young’s modulus on the coupled QCR and pillars with a diameter of 20 µm, a center-to-center spacing of 40 µm and a density of 2,500 kg/m3 was investigated. The results indicate that multiple vibration modes can be obtained based on Young’s modulus. Notably, in the case of the QCR–pillar in air, the second vibration mode occurred at a critical Young’s modulus of 0.2 MPa, whereas the first mode was observed at 3.75 Mpa. The vibration phase analysis revealed phase-veering behavior at the critical Young’s modulus, which resulted in a sudden jump-and-drop frequency shift. In addition, the results show that the critical Young’s modulus is dependent on the surrounding environment of the pillar. For instance, the critical Young’s modulus for the first mode of the pillar is approximately 3.75 Mpa in air, whereas it increases to 6.5 Mpa in water.
Originality/value
It was concluded that the performance of coupled QCR–pillar devices significantly depends on the pillar material. Therefore, choosing pillar material at critical Young’s modulus can lead to the maximum frequency shift of coupled QCR–pillar devices. The model developed in this work helps the researchers design pillars to achieve maximum frequency shift in their measurements using coupled QCR–pillar.
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Asif Ur Rehman, Kashif Azher, Abid Ullah, Celal Sami Tüfekci and Metin Uymaz Salamci
This study aims to describe the effects of capillary forces or action, viscosity, gravity and inertia via the computational fluid dynamics (CFD) analysis. The study also includes…
Abstract
Purpose
This study aims to describe the effects of capillary forces or action, viscosity, gravity and inertia via the computational fluid dynamics (CFD) analysis. The study also includes distribution of the binder droplet over the powder bed after interacting from different heights.
Design/methodology/approach
Additive manufacturing (AM) has revolutionized many industries. Binder jetting (BJT) is a powder-based AM method that enables the production of complex components for a wide range of applications. The pre-densification interaction of binder and powder is vital among various parameters that can affect the BJT performance. In this study, BJT process is studied for the binder interaction with the powder bed of SS316L. The effect of the droplet-powder distance is thoroughly analysed. Two different droplet heights are considered, namely, h1 (zero) and h2 (9.89 mm).
Findings
The capillary and inertial effects are predominant, as the distance affects these parameters significantly. The binder spreading and penetration depth onto the powder bed is influenced directly by the distance of the binder droplet. The former increases with an increase in latter. The binder distribution over the powder bed, whether uniform or not, is studied by the stream traces. The penetration depth of the binder was also observed along the cross-section of the powder bed through the same.
Originality/value
In this work, the authors have developed a more accurate representative discrete element method of the powder bed and CFD analysis of binder droplet spreading and penetration inside the powder bed using Flow-3D. Moreover, the importance of the splashing due to the binder’s droplet height is observed. If splashing occurs, it will produce distortion in the powder, resulting in a void in the final part.
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Rainald Löhner, Lingquan Li, Orlando Antonio Soto and Joseph David Baum
This study aims to evaluate blast loads on and the response of submerged structures.
Abstract
Purpose
This study aims to evaluate blast loads on and the response of submerged structures.
Design/methodology/approach
An arbitrary Lagrangian–Eulerian method is developed to model fluid–structure interaction (FSI) problems of close-in underwater explosions (UNDEX). The “fluid” part provides the loads for the structure considers air, water and high explosive materials. The spatial discretization for the fluid domain is performed with a second-order vertex-based finite volume scheme with a tangent of hyperbola interface capturing technique. The temporal discretization is based on explicit Runge–Kutta methods. The structure is described by a large-deformation Lagrangian formulation and discretized via finite elements. First, one-dimensional test cases are given to show that the numerical method is free of mesh movement effects. Thereafter, three-dimensional FSI problems of close-in UNDEX are studied. Finally, the computation of UNDEX near a ship compartment is performed.
Findings
The difference in the flow mechanisms between rigid targets and deforming targets is quantified and evaluated.
Research limitations/implications
Cavitation is modeled only approximately and may require further refinement/modeling.
Practical implications
The results demonstrate that the proposed numerical method is accurate, robust and versatile for practical use.
Social implications
Better design of naval infrastructure [such as bridges, ports, etc.].
Originality/value
To the best of the authors’ knowledge, this study has been conducted for the first time.
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Nurul Amira Zainal, Najiyah Safwa Khashi'ie, Iskandar Waini, Abdul Rahman Mohd Kasim, Roslinda Nazar and Ioan Pop
The evaluation of high thermal efficiency has actively highlighted the unique behaviour of hybrid nanofluid. Thus, the purpose of this paper is to emphasize the hybrid nanofluid’s…
Abstract
Purpose
The evaluation of high thermal efficiency has actively highlighted the unique behaviour of hybrid nanofluid. Thus, the purpose of this paper is to emphasize the hybrid nanofluid’s stagnation point in three-dimensional flow with magnetic field.
Design/methodology/approach
The defined ordinary differential equations systems are addressed using the bvp4c solver.
Findings
The results indicate that using dual solutions is possible as long as the physical parameters remain within their specified ranges. Hybrid nanofluid flow has been recognised for its superior heat transfer capabilities in comparison to both viscous flow and nanofluid flow. Furthermore, it has been demonstrated in the current study that augmenting the volume concentration of nanoparticles leads to a corresponding enhancement in the rate of heat transfer. When the velocity gradients ratio is augmented, there is a corresponding reduction in the thermal performance. The separation value grows as the magnetic parameter rises, which signifies the expansion of the boundary layer.
Originality/value
The originality of the paper highlights the general mathematical hybrid model of the three-dimensional problem with the magnetohydrodynamics (MHD) effect in the stagnation point flow. The comprehensive examination of the suggested model has not yet been thoroughly addressed in prior research.
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