International Journal of Modeling, Simulation, and Scientific Computing

In this study, a numerical approach is established to design a beam coupled to a Voice Coil Motor (VCM) with the aim to maximize the displacement in the inductive transducer. A finite element model is developed to simulate a VCM with different beams applying a harmonic analysis. The VCM is extracted from a recycled hard disk drive (HDD) and a parametric modal analysis is performed to identify the material parameters of the HDD and the beam. These parameters are obtained comparing the real vibration modes and natural frequencies (VCM-beam) with those determined from the finite element model. A numerical-experimental case study is carried out to demonstrate that if a beam is designed for a specific low frequency vibration between 0 and $10\mathrm{\text{Hz}}$, the displacements are maximized in the VCM. For this purpose, real acceleration measurements taken from three individuals are used to provide the vibration signals in the numerical model. A beam is designed for one of the individuals using the natural frequency values determined from the measured signals. Results show that the displacements are maximized in the model which coincides with the natural frequency of the chosen individual. The main purpose of this research is to establish a design tool for energy harvesting purposes with VCM based on low frequency vibration sources as for example gait motions.

In this paper, a model of an ungrounded reactor winding is developed for transient voltage studies. The developed model is a black box model where the state-space model is developed using the directly measured admittance matrix of the reactor winding. Furthermore, an improved model is developed, where the accuracy of the admittance matrix measurement set in the low frequency band is obtained indirectly using an additional set of voltage ratio measurements. When the measured admittances are low, the accuracy of the diagonal admittance vectors in the low frequency band is low as well. However, the accuracy at low frequencies obtained using the indirect measurements is improved at nodes with the lowest admittances. In this paper, different approaches for indirect measurements are studied and the most accurate method is identified considering the physical structure of windings.

The purpose of this work is to determine the best analytical approximation of the differential cross-sections, used in Monte Carlo simulation, to study the electron and positron slowing down in solid targets in the energy range up to 10keV. For this, our comparative study has been carried out on the angular distribution of the scattering angle, the elastic total and the first transport cross-sections which are the essential quantities used generally in both the electron and the positron transport studies by using either stochastic or deterministic methods. Indeed, the obtained results using the relativistic partial wave expansion method and the backscattering coefficient (BSC) experimental data are used as criteria to evaluate the used model.

A fluid jet ejected from micron size nozzle is a commonly occurring phenomenon in biomedical engineering, printing technology and micro-fluidic applications. Disintegration of a jet into drops occurs due to disturbances induced by external sources. This work explores the various sources of perturbation and their effect on jet disintegration through numerical simulation of a two-dimensional non-isothermal model. The mathematical approach uses a novel technique to combine analytical solutions for the energy balance equation in the radial direction to solve the complete two dimensional problem. The two dimensional energy balance equation is simultaneously solved together with the axi-symmetric Navier–Stokes equations using the slender-jet approximation to predict jet velocity. The energy balance takes into account of peripheral heat transfer to the environment through analytical expressions derived from radial approximations. The model helps in understanding the factors in dynamic temperature variations that eventually render the jet unstable. The distinguishing aspect of this work is the analysis of the effect of a periodic thermal perturbation applied at any point in the domain of a progressive jet, a situation typically encountered in thermal inkjet printers and not considered previously. Results presented for non-isothermal jets which are both stationary and moving illustrate the effect of jet velocity in propagation of perturbation and subsequent drop formation. The major contribution of this numerical study is that it provides an insight on novel ways of controlling droplet formation in bubble jet printers. This study demonstrates that thermal disturbance propagating from periodic heating can be manipulated to shape the droplets and control their breakage point along the jet.

A mathematical model is presented here to investigate the effects of environmental pollution, intensified by urbanization, on the density of human population. Here, urbanization is assumed to grow with constant rate and also, induced through growing population and the corresponding population pressure. The model analysis, qualitatively and numerically, show that though the growth of population or population pressure is responsible for the growing urbanization, but for very large increase of urbanization, the population may not survive in the long run due to environmental pollution driven by urbanization.

The paper describes a novel mathematical model to study the physics of fully ionized plasma flow through MPD thrusters otherwise known as magnetoplasmadynamic thrusters. The developed model consists of a set of differential equations obtained by coupling the Navier–Stokes equations with Maxwell’s equations. The model developed was tested for various 1D and 1.5D cases. These simulations have been carried out for a special case of geometries called Tikhonov fitted geometries for alleviating the instability phenomenon commonly known as onset phenomenon in self-field MPD thrusters. The work was also extended to applied field MPD thrusters. A new equation for magnetic field was introduced to incorporate a virtual cathode. All the computations were carried out using a higher order integration scheme. The results obtained were found to be in good agreement with the previous work done on similar models.

Healthcare systems engineering in emergency departments (EDs) are developing rapidly in the world nowadays. Fast track (FT) as a rapid treatment system is considered to facilitate ED patient flow. To know how FT can improve the performance of ED, one should study the best configuration of resources for implementation of FT. This research presents a pattern for implementation of FT systems in hospital EDs using healthcare simulation paradigms. Simulation-based optimization model uses modeling and simulation capabilities to generate configurations of FT resources and its patient prioritization pattern with Arena${}^{\mathrm{\text{®}}}$ simulation software. A decision making method is used to select the optimal configuration based on pre-specified performance indicators. The results imply that the proposed FT implementation pattern is efficient and capable of improving patient flow.

Numerical simulation results of the Coulomb explosion pathways of cooled water and heated glycol droplets electrically charged to the critical Rayleigh limit are presented, calculated using an axi-symmetric finite element scheme previously used for the same problem [Radcliffe A. J., Non-conforming finite elements for axisymmetric charged droplet deformation dynamics and Coulomb explosions, Int. J. Num. Meth. Fluids 71:249–268, (2013), doi:10.1002/fld.3667.] which has been adapted to use arbitrary Lagrangian–Eulerian (ALE) methods and a novel tip reconstruction technique in order to greatly improve its accuracy in matching available experimental data.

Commutator free method is an effective method for solving rotating integration. Numerical examples show that the use of the proposed combining method can achieve the same order accuracy with less computation than other geometry integration method. However, it is difficult to be directly applied to mechanic dynamics solutions. In this paper, commutator free method which is often applied to rotation integration and classical Runge–Kutta (RK) method which is usually operated in Linear space are combined to solve the multi-body dynamic equations. The explicit Runge–Kutta coefficients are reconstructed to meet different order accuracy integration methods. The reconstruction method is discussed and coefficients are given. With this method, the dynamic equations can be solved accurately and economically without much modification on the classical numerical integration. Moreover, CG method and CF method can also be combined with adaptive RK method without many changes. Finally, the results of the examples show that with less computation, fourth-order combining method is as accurate as fourth-order Crouch–Grossman algorithm.

The underwater acoustics is primary and most effective method for underwater object detection and the complex underwater acoustics battlefield environment can be visually described by the three-dimensional (3D) energy field. Through solving the 3D propagation models, the traditional underwater acoustics volume data can be obtained, but it is large amount of calculation. In this paper, a novel modeling approach, which transforms two-dimensional (2D) wave equation into 2D space and optimizes energy loss propagation model, is proposed. In this way, the information for the obtained volume data will not be lost too much. At the same time, it can meet the requirements of data processing for the real-time visualization. In the process of volume rendering, 3D texture mapping methods is used. The experimental results are evaluated on data size and frame rate, showing that our approach outperforms other approaches and the approach can achieve better results in real time and visual effects.

With the development of computer technique, performance evaluation of complex products is playing an increasingly critical role in ensuring product quality and improving development process. An extensible comprehensive performance evaluation framework with the integration of effective group decision-making algorithms could be a supporting tool to achieve an efficient evaluation process and reduce comprehensive evaluation difficulty. This paper aims to provide a evaluation framework with friendly interactive operation and extensive expansibility, which adopts a multi-expert evaluation approach based on fuzzy, analytical hierarchy process (FAHP) and Dempstere–Shafer (DS) theory (FADS) in order to consider experts’ relative importance degree. In addition, an extensible evaluation process and related auxiliary functions are implemented in the framework, including the establishment of an assessment index system, integration and calls of multiple types of testing data preprocessing methods and index assessment methods suitable for small sample data, graphical result display and data analysis, etc. Finally, performance evaluation cases of two models of airborne radar anti-jamming are presented to verify the feasibility and expansibility of our assessment framework. The group decision-making method shows its effectiveness compared with the experimental evaluation results by the FAHP researched method.

The simulation on benchmarks is a very simple and efficient method to evaluate the performance of the algorithm for solving flexible job shop scheduling model. Due to the assignment and scheduling decisions, flexible job shop scheduling problem (FJSP) becomes extremely hard to solve for production management. A discrete multi-objective particle swarm optimization (PSO) and simulated annealing (SA) algorithm with variable neighborhood search is developed for FJSP with three criteria: the makespan, the total workload and the critical machine workload. Firstly, a discrete PSO is designed and then SA algorithm performs variable neighborhood search integrating two neighborhoods on public critical block to enhance the search ability. Finally, the selection strategy of the personal-best individual and global-best individual from the external archive is developed in multi-objective optimization. Through the experimental simulation on matlab, the tests on Kacem instances, Brdata instances and BCdata instances show that the modified discrete multi-objective PSO algorithm is a promising and valid method for optimizing FJSP with three criteria.

This paper proposes a novel integrated guidance and control (IGC) method combining dynamic surface control (DSC) and active disturbance rejection control (ADRC) for the guidance and control system of hypersonic reentry missile (HRM) with bounded uncertainties. First, the model of HRM is established. Second, the proposed IGC method based on DSC and ADRC is designed. The stability of closed-loop system is proved strictly. It is worth mentioning that the ADRC technique is used to estimate and compensate the disturbance in the proposed IGC system. This makes the closed-loop system a better performance and reduces the chattering caused by lumped disturbances. Finally, a series of simulations and comparisons with a 6-DOF non-linear missile that includes all aerodynamic effects are demonstrated to illustrate the effectiveness and advantage of the proposed IGC method.

An advanced erosion model that correlates two model parameters—the energies required to remove unit mass of target material during cutting wear and deformation wear, respectively, with particle velocity, particle size and density, as well as target material properties, is proposed. This model is capable of predicting the erosion rates for a material under solid-particle impact over a specific range of particle velocity at the impingement angle between $0^{\circ }$ and $90^{\circ }$, provided that the experimental data of erosion rate for the material at a particle velocity within this range and at impingement angles between $0^{\circ }$ and $90^{\circ }$ are available. The proposed model is applied on three distinct types of materials: aluminum, perspex and graphite, to investigate the dependence behavior of the model parameters on particle velocity for ductile and brittle materials. The predicted model parameters obtained from the model are validated by the experimental data of aluminum plate under Al₂O₃ particle impact. The significance and limitation of the model are discussed; possible improvements on the model are suggested.

Simulation is a powerful technique in evaluating and improving the performance of complex systems. In order to improve the efficiency of simulation experiment design, analysis and evaluation, auxiliary tools are required. Unfortunately, existing tools are usually not meeting the requirements of simulation. Moreover, the restricted interfaces, reusability and expandability influence their efficiency to a certain extent. In this paper, an integrated software environment, HIT-SEDAES, is designed for solving these problems. A process model of simulation experiment design, analysis and evaluation is introduced to guide the development of the software environment. And several solutions are proposed to solve key problems in this development. Finally, an application is used to illustrate how the software environment works for the problems of model validation, effectiveness evaluation and performance analysis.

The main aim of this paper is to develop an approach based on trapezoidal fuzzy numbers to optimize transportation problem in fuzzy environment. The present algorithm has representation of availability, demand and transportation cost as trapezoidal fuzzy numbers. This algorithm is found quicker in terms of runtime as comparison to fuzzy VAM discussed in [Kaur A., Kumar A., A new method for solving fuzzy transportation problem using ranking function, Appl. Math. Model. 35:5652–5661, 2011; Ismail Mohideen S., Senthil Kumar P., A comparative study on transportation problem in fuzzy environment, Int. J. Math. Res. 2:151–158, 2010]. On the other hand this technique gives much better results than some classical methods like north-west corner and least cost method. Another benefit of this algorithm is that for certain transportation problems it directly gives optimal solution. It is one of the simplest methods to apply and perceive. Practical usefulness of the new method over other existing methods is demonstrated with two numerical examples.

To resimulate a customized fluid derived product by analyzing an existing fluid is significant and difficult. This paper proposes a driven model recovery method, which is challenging in fluid resimulation customization. First, fluid physical properties are calculated under the constraints of appearance and dynamic behavior of the example water. Second, a hybrid particle lattice Boltzmann method for shallow water (LBMSW) is recovered from the dynamic geometry on fluid surface. As it is found that the resimulation details fade gradually with LBMSW auto-advection, a physically-based enhancement scheme is presented. A nonlinear algorithm is introduced to stretch the faded density to retain resimulation details. Experiments show that the proposed approach can obtain more realistic resimulation products in several challenging scenarios.

It is hard to model a complex system by simply combining its partial characteristics. This paper presents a multi-view collaborative modeling method for complex system. Multi users, multi subjects, multi granularities and multi models in complex system modeling are unified to multi views. The principles and schemes for the decomposition of complex systems are introduced. According to the principle of separation of concerns, a complex system can be decomposed to a variety of model views. Collaborative modeling means that the views can be associated and integrated to form complete system model through their semantic. According to the form of representation, the models are generalizes to three kinds, i.e., view models, semantic models and storage models, which provides a unified framework for conversion and mapping between the models. Under the guidance of the method, a tool for the modeling of warship C2 system is developed. Applications show that the tool can support collaborative modeling and design for C2 system outstandingly.

In advanced gas turbine technology, lean premixed combustion is an effective strategy to reduce peak temperature and thus, NO${}_X$ emissions. The swirler is adopted to establish recirculation flow zone, enhancing mixing and stabilizing the flame. Therefore, the swirling flow is dominant in the combustor flow field and has impact on the vane. This paper mainly investigates the swirling flow effect on the turbine first stage vane cooling system by conducting a group of numerical simulations. Firstly, the numerical methods of turbulence modeling using RANS and LES are compared. The computational model of one single swirl flow field is considered. Both the RANS and LES results give reasonable recirculation zone shape. When comparing the velocity distribution, the RANS results generally match the experimental data but fail to at some local area. The LES modeling gives better results and more detailed unsteady flow field. In the second step, the RANS modeling is incorporated to investigate the vane film cooling performance under the swirling inflow boundary condition. According to the numerical results, the leading edge film cooling is largely altered by the swirling flow, especially for the swirl core-leading edge aligned case. Compared to the pressure side, the suction side film cooling is more sensitive to the swirling flow. Locally, the film cooling jet is lifted and turned by the strong swirling flow.

This paper mainly studies the comparison of the global vehicle models and the effects of the inertial parameters due to the center of gravity (CG) positions when we consider that the vehicle has only one CG. This paper proposes a new nonlinear model vehicle model which considers both unsprung mass and sprung mass CG. The CG positions and inertial parameters effects are analyzed in terms of the published vehicle dynamics models. To this end, two 14 degree-of-freedom (DOF) vehicle models are developed and compared to investigate the vehicle dynamics responses due to the different CG height and inertial parameters concepts. The proposed models describe simultaneously the vehicle motion in longitudinal, lateral and vertical directions as well as roll, pitch and yaw of the vehicle about corresponding axis. The passive and active moments and the forces acting on the vehicle are also described and they are considered as a direct consequence of acceleration, braking and steering maneuvers. The proposed model $M_1$ takes both the CG of sprung mass, unsprung mass and total vehicle mass into account. The second model $M_2$ assumes that the vehicle is one solid body which has a single CG as reported in majority of literature. The two vehicle models are compared and analyzed to evaluate vehicle ride and handling dynamic responses under braking/acceleration and cornering maneuvers. Simulation results show that the proposed model $M_1$ could offer analytically some abilities and driving performances, as well as improved roll and pitch in a very flexible manner compared to the second model $M_2$.

The detection capabilities of passive electronic warfare reconnaissance equipment have substantially increased during recent years. Correspondingly, the radar equipment is required to take various means to improve the radio frequency (RF) stealth performance to ensure the transmitted RF signal does not get intercepted. However, traditional evaluation methods on RF stealth performance cannot accurately evaluate the RF stealth capabilities of new system radar. In this study, a joint interception probability evaluation model on RF stealth performance was established, which divided the interception process into two parts: front interception and system interception. Various RF stealth means adopted by different radar equipment were taken into consideration to improve the applicability of this model. Simulation results show that this model is able to effectively characterize almost all the aspects of the RF stealth features and can serve as a good reference to evaluate RF radar stealth performance comprehensively.

The performance of AlInSb/InSb heterostructure with various parameters is considered with T-Cad simulation. As the heterojunctions are having more advantageous properties that is a real support for so many application such as solar cells, semiconductor cells and transistors. Special properties of semiconductors are discussed here with various parameters that are depending up on the performance of accurate device [Pardeshi H., Pati S. K., Raj G., Mohankumar N., Sarkar C. K., J. Semicond. 33(12):124001-1–124001-7, 2012]. The maximum drain current density is achieved with improving the density of two-dimensional electron gas (2DEG) and with high velocity. High electron mobility transistor (HEMT) structure is used with the different combinations of layers which have different bandgaps. Parameters such as electron mobility, bandgap, dielectric constant, etc., are considered differently for each layer [Zhang A., Zhang L., Tang Z., IEEE Trans. Electron Devices 61(3):755–761, 2014]. The high electron mobility electrons are now widely used in so many applications. The proposed work of AlInSb/InSb heterostructure implements the same process which will be a promise for future research works.