Preface
Many people have not heard about microfluidics. This is somewhat astonishing as microfluidics surrounds us.
Microfluidics is the scientific disciplines that studies and employs the fluid physics at the micro- and nanometer scale. Fluids do interesting things when probed in such miniaturized systems. Capillarity is one of these effects we are familiar with. If you ever dipped a tissue paper in water and watched the water penetrate it you may have wondered what forces drive it. This is microfluidics. However, nowadays, there is an ample number of technical systems which make use of microfluidics ranging from analytical devices in biomedical engineering and the life sciences all the way to systems such as inkjet printers.
Microfluidics shares many of its fundamentals with classical fluid mechanics. Many students struggled with fluid mechanics during their studies because it is a discipline that requires a quite sound understanding of engineering mathematics. As a consequence, students (as well as established scientists) often take rather heuristic approaches when designing microfluidic systems. A system is characterized and optimized solely on experimental data. Very often, the findings are published omitting pretty much all fluid mechanical fundamentals and (very often) without any theoretical model. Equations are often copied from textbooks and simply applied without real understanding of what the equations actually describe. Whenever a more complex fluidic system is to be designed many researchers default to numerical software packages for providing an assessment of the system prior to device manufacturing. Very often, these extensive calculations are not necessary as there would have been a very simple theoretical model which would have been sufficient to understand the fluid mechanics of the system.
This book is intended for all students and researchers who want to understand the fundamentals of fluid mechanics. The book does not simply state the most important equations, it derives them. I believe that by providing the derivation of an equation, it will be significantly simpler to understand its meaning and its applicability. The reader will require very little prior knowledge when starting with this book. All mathematical concepts, tricks and methods used will be introduced and explained. The book will elucidate analytical techniques as well as numerical methods. It serves as a practical coursebook for those who want to deepen their knowledge, e.g., of numerical methods as well as for those who are already very experienced in fluid mechanics but simply want to understand where a specific formula (such as, e.g., the velocity distribution in a given channel cross-section) actually comes from.
The book comes with a number of worksheets written in Maple. These worksheets serve as templates to experiment with the equations derived and visually check which changes in the fluid mechanics are induced by changing certain variables. They can be used as basis for theoretical assessment of many microfluidic systems. This book contains many listings written in C which elucidate the numerical methods commonly used in fluid mechanics and microfluidics. In the supplementary you will also find a compiled DLL with exports functions that can be used to solve three-dimensional flow problems numerically. These functions are developed within this book together will all necessary numerical fundamentals. By following the book chapter-by-chapter you will gain a very detailed understanding of engineering mechanics, fluid mechanics and numerical methods.
Have fun exploring the fluid mechanics of microfluidics!
November 2016