Preface

Nowadays mathematical modeling and numerical simulations play an important role in life and natural science. Numerous researchers are working in developing different methods and techniques to help understand the behavior of very complex systems, from the brain activity with real importance in medicine to the turbulent flows with important applications in physics and engineering. This book presents an overview of some models, methods, and numerical computations that are useful for the applied research scientists and mathemati‐ cians, fluid tech engineers, and postgraduate students.

The first section of the book presents models and simulations for the analysis of the behav‐ ior of some parts of the human body. In Chapter 1, Chen and Calhoun discuss some imag‐ ing (fMRI) aspects of brain functional (BOLD) activity. In Chapter 2, Bauer and Paulus study the biomechanical behavior of a lumbar spine model that take the spinal structures with their specific material properties into account. In Chapter 3, Kitajima et al. investigate some aspects of computational neuroscience by using RC and RCL circuits to model the neurons and the cell membrane. The last chapter of this section, Chapter 4 by Jackowska-Zduniak, introduces a two-coupled van der Pol equation model to describe the heart action potential to recreate some pathological behavior, such as the most common (AVNRT) tachycardia.

The second section of the book presents some mathematical and numerical methods to inte‐ grate different types of differential equations. In Chapter 5, Khan et al. simulate fractional differential equations by using Chebyshev- and Legendre (ChSANN and LSANN)-simulat‐ ed annealing neural networks. In Chapter 6, Sweilam and Assiri introduce and numerically study some real-life model problems that can be formulated as ordinary differential equa‐ tions. In Chapter 7, Motsa et al. explore the application of a novel multi-domain spectral collocation method for solving general nonlinear Lane-Emden-type differential equations. Finally, in Chapter 8, Khan et al. provide a comprehensive discussion of systems of fuzzy fractional differential models in imprecise environment.

The third section of the book presents different problems of heat transfer where fluids are involved. In Chapter 9, Castro et al. analyze the convection heat transfer in an experimental heat exchanger using experimental and numerical simulation data. In Chapter 10, Ludowski et al. propose solving steady-state inverse heat transfer problems using Computational Flu‐ id Dynamics (CFD) software. In Chapter 11, Lopes addresses the physical principles and numerical models implemented in the software package EasyCFD. In the last chapter of this section, Chapter 12, Shateyi et al. analyze the problem of magnetohydrodynamic (MHD) mi‐ cro-polar fluid, heat and mass transfer over unsteady stretching sheet through a porous me‐ dium.

The final section of the book presents some models and techniques for turbulent flows. In Chapter 13, Alonzo-García et al. provide an overview of the technical, theoretical, and nu‐ merical applications of Computational Fluid Dynamics (CFD) using the finite volume tech‐ nique, restricted to incompressible turbulent flows. In Chapter 14, Lauk et al. investigate a novel 3D model based on the Reynolds Turbulence Stress Model (RSTM) closure of equa‐ tions of carrier and particulate phases for channel turbulent flows. In Chapter 15, Ketabdari discusses and evaluates different free surface simulation methods based on computational grid. Finally, in Chapter 16, Mejía et al. address the use of Large Eddy Simulation (LES) for analyzing transport and mixing of passive and reactive scalars at high Schmidt regimes.

As the editor of this book, I would like to thank all the authors who have contributed to this volume as well as the reviewers for their assessment. Also, I express my gratitude to the InTech editorial staff for their invitation to be editor of an initial book project that, with the particular help of Ms. Iva Lipovic, the publishing process manager (PPM), we have arrived to convert in this new InTech book. Finally, at this moment where my father recently passed away, I dedicate all this effort to his memory and to him, Ricardo López-Barasoain (1935– 2015), from Villafranca, Navarra, Spain. Of course, the rest of my family and all my friends and advisors are not forgotten in this dedicatory final paragraph.

> **Ricardo López-Ruiz** University of Zaragoza Spain

**Models and Applications in Medicine**

The final section of the book presents some models and techniques for turbulent flows. In Chapter 13, Alonzo-García et al. provide an overview of the technical, theoretical, and nu‐ merical applications of Computational Fluid Dynamics (CFD) using the finite volume tech‐ nique, restricted to incompressible turbulent flows. In Chapter 14, Lauk et al. investigate a novel 3D model based on the Reynolds Turbulence Stress Model (RSTM) closure of equa‐ tions of carrier and particulate phases for channel turbulent flows. In Chapter 15, Ketabdari discusses and evaluates different free surface simulation methods based on computational grid. Finally, in Chapter 16, Mejía et al. address the use of Large Eddy Simulation (LES) for analyzing transport and mixing of passive and reactive scalars at high Schmidt regimes.

As the editor of this book, I would like to thank all the authors who have contributed to this volume as well as the reviewers for their assessment. Also, I express my gratitude to the InTech editorial staff for their invitation to be editor of an initial book project that, with the particular help of Ms. Iva Lipovic, the publishing process manager (PPM), we have arrived to convert in this new InTech book. Finally, at this moment where my father recently passed away, I dedicate all this effort to his memory and to him, Ricardo López-Barasoain (1935– 2015), from Villafranca, Navarra, Spain. Of course, the rest of my family and all my friends

> **Ricardo López-Ruiz** University of Zaragoza

> > Spain

and advisors are not forgotten in this dedicatory final paragraph.

X Preface
