Preface

In many fields, modelling and simulation are integral and therefore essential to business and research. Modelling and simulation provide the capability to enter fields that are either inaccessible to traditional experimentation or where carrying out traditional empirical inquiries is prohibitively expensive. The role of modelling and simulation in engineering and various applications such as computational fluid dynamics, finite element analysis, and others has been underestimated for a long time. However, with a growing complexity of application scenarios as well as numerical algorithms and hardware architectures, the need for sophisticated methods from numerical analysis and computer science has become more important. The growth in computing power has revolutionized the use of realistic mathematical models in science and engineering, and numerical analysis is required to implement these detailed models of the world.

A computer simulation is the execution of a model, represented by a computer program that gives information about the system being investigated. The simulation approach of analyzing a model is opposed to the analytical approach, where the method of analyzing the system is purely theoretical. As this approach is more reliable, the simulation approach gives more flexibility and convenience. Modelling and simulation offer people the chance to develop an understanding of their problem domain by building a simulation of the problem space in which they are interested.

The modelling and simulation identify more key stages in a successful simulation cycle: implementation, exploration and visualization, validation, and embedding.

The book provides and discusses different examples from engineering, as well as where and how numerical methods contribute to more efficient simulation environments. There are 7 chapters in the book, covering different aspects of modelling and simulation in engineering and technology.

In Chapter 1, a three-dimensional simulation technology for physical processes in concentric hydraulic brakes with a throttling-groove partly filled hydraulic cylinder is considered. The technology is based on the numerical solution of a system of Navier-Stokes equations. Free surface tracking is provided by the volume of fluid method. The results of hydraulic brake simulations in the counter-recoil regime are reported and compared to experimental data. The performance of the hydraulic brake is studied as a function of the fluid mass and firing elevation of the gun.

Chapter 2 addresses the behavior of functionally graded solids under dynamic impact loading within the framework of linear elasticity using the parallel explicit algorithm. Numerical examples are presented that verify the dynamic explicit finite element code and demonstrate the dynamic response of graded materials. A threepoint bending beam made of epoxy and glass phases under low velocity impact is studied. Finite element modeling and simulation discussed herein can be a critical tool in helping to understand the physics behind the dynamic events.

Chapter 3 discusses the case studies that revealed premature failures of stiffer elements prior to utilising the full capacity of more deformable elements within the same system. From a design perspective, it is important to understand that the dynamic-load capacity of a ground support system depends not only on the capacity of its reinforcement elements but also, and perhaps most importantly, on their compatibility with other elements of the system and on the strength of the connections. The failure of one component of the support system usually leads to the failure of the system.

Chapter 4 estimates criteria for mathematical descriptions in the form of ordinary differential equations. Adequate mathematical descriptions can increase the objectivity of the results of mathematical modeling for future use. These descriptions make it possible and reasonable to use the results of mathematical modeling to optimize and predict the behavior of physical processes. Interrelations between criteria are considered. The proposed criteria are easily transferred to mathematical descriptions in algebraic form.

In Chapter 5, the power flow model of a power system is built using the relevant network, load, and generation data. Outputs of the power flow model include voltages at different buses, line flows in the network, as well as system losses. These outputs are obtained by solving nodal power balance equations. Since these equations are nonlinear, iterative techniques are commonly used to solve this problem. The chapter will provide an overview of different techniques used to solve the power flow problem.

Chapter 6 shows how different approaches can be adopted to model three emerging semiconductor devices namely, silicon-on-insulator four gate transistor, single photon avalanche diode, and insulator-metal transistor device.

In Chapter 7, the results of numerical simulation of heat transfer on a 5-inch hemispherical concave nose at a Mach number of 2 are reported and compared with the available experimental data. Different turbulence models and different discretization schemes are also examined.

The book promotes open discussion between research institutions, academia, and industry from around the globe on research and development of enabling technologies. The book covers many aspects of theory and practice, which deliver essential contributions and provide their input and support to the cooperative efforts.

> Dr. Konstantin Volkov MEng. MSc. PhD. DSc. CEng. MIMechE. MinstP. FHEA., Department of Mechanical and Automotive Engineering, School of Engineering and the Environment, Faculty of Science, Engineering and Computing, Kingston University, London, United Kingdom

### Chapter 1
