7R45. Micro Flows: Fundamentals and Simulation. - GEM Karniadakis (Div of Appl Math, Brown Univ, 182 George St, Providence RI 02912) and A Beskok (Dept of Mech Eng, Texas A&M Univ, TAMU 3123, College Station TX 77843-3123). Springer-Verlag, New York. 2002. 340 pp. ISBN 0-387-95324-8. $69.95.
Reviewed by M Gad-el-Hak (Dept of Aerospace and Mech Eng, Univ of Notre Dame, Notre Dame IN 46556).
Fluid flows in or around microdevices is the subject of the present book. Microelectromechanical systems (MEMS) refer to devices that have characteristic length of less than 1 mm, but more than 1 micron that combine electrical and mechanical components, and that are fabricated using integrated circuit batch-processing technologies. Electrostatic, magnetic, pneumatic, and thermal actuators, motors, valves, ducts, gears, and tweezers of less than 100-micron size have been fabricated. These have been used as sensors for pressure, temperature, mass flow, velocity and sound, as actuators for linear and angular motions, and as simple components for complex systems such as micro-heat-engines and micro-heat-pumps. The multidisciplinary field of MEMS has witnessed explosive growth during the last decade, and the technology is progressing at a rate that far exceeds that of our understanding of the physics involved in the operation as well as the manufacturing of those minute machines. The present book attempts to bridge this gap, focusing exclusively on flow physics within microdevices. It is perhaps the first of the genre to do so.
Microdevices often involve mass, momentum, and energy transport. Modeling gas and liquid flows through MEMS may necessitate including slip, rarefaction, compressibility, intermolecular forces, electrokinetics, dielectrophoreses, and other unconventional effects. In this book, the two authors, both renowned authorities in the modeling and numerical simulation of microflows, provide a methodical approach to flow modeling for a broad variety of microdevices. The continuum-based Navier–Stokes equations—with either the traditional no-slip or slip-flow boundary conditions—work only for a limited range of Knudsen numbers above which alternative models must be sought. These include molecular dynamics (MD), Boltzmann equation, direct simulation Monte Carlo (DSMC), and other deterministic or probabilistic molecular models. The book broadly surveys available methodologies to model and compute transport phenomena within microdevices. It includes a pretty inclusive list of numerical strategies. Considering the extensive microflow research conducted by the authors, the coverage here emphasizes their own work—including previously unpublished material—although other research is covered as well. The book’s preface indicates that the original draft was based largely on the doctoral thesis of the junior author.
The book contains 10 chapters: basic concepts and technologies; governing equations; shear-driven and separated flows; pressure-driven flows in the slip regime; pressure-driven flows in the transition and free-molecular regimes; thermal effects; prototype applications; electrokinetically driven liquid flows; numerical methods for continuum simulations; and numerical methods for atomistic simulations. It seems that the last two chapters would have been better placed right after the governing equations. The authors constantly refer to Chapters 9 and 10 in their Chapters 3–8. The chapter on applications of gas microflows is too terse and would perhaps have fit the flow of the book better as part of the introduction. As compared to gas flows in microdevices, much less is known about liquid microflows, and the book reflects well this state of affairs. One should add that selecting the material for a monograph when the research field is so new as well as active is never an easy task, and the present authors should be complimented for a job well done.
Among recent books that addressed the physics of microdevices, the present one—covering only one branch of that physics— is perhaps the best of the bunch. This is a graduate-level monograph which is rigorous yet readable. The book covers both theoretical and numerical approaches to microflow problems, including ones with heat transfer. The writing is lucid and focused, never winding or verbose. The text is complemented with plenty of appropriate line drawings, sketches, and photographs. The list of references at the end is comprehensive. All chapters have good prologues, but unfortunately, none has a graceful epilogue. Finishing a particular chapter, a reader may end up wondering, so what?
This reviewer was not impressed with the production job performed by Springer-Verlag. As is more likely today for obvious cost-saving reasons, it appears that the book was published from an author-supplied, camera-ready manuscript, without the benefit of a dainty copy editor or a fastidious typesetter. Numerous typographical and grammatical errors crept through the final product and blemished what could have been an outstanding book. The book title and the table of contents each contain one glaring misshape. Units are italicized when they should not be. Hyphens, en dashes, and em dashes are confused with each other. Those are all minor quibbles, but when one is looking at a masterpiece painting, a scratch or two on the frame can be an easily avoided eye sore.
Despite the few negatives, Micro Flows: Fundamentals and Simulation has a lot to offer and is certainly recommended as a good place to start for MEMS students interested in flow physics. Every library should acquire this book, and for personal bookshelves, the price is not too excessive, at least by today’s standards.
