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Ebook Fundamentals of fluid mechanics: Part 2

(BQ) Part 2 book "Fundamentals of fluid mechanics" has contents: Dimensional analysis, similitude, and modeling; viscous flowin pipes, flow over immersed bodies, open-channel flow, compressible flow, turbomachines. | JWCL068_ch07_332-382.qxd 9/23/08 10:46 AM Page 332 7D imensional Analysis, Similitude, and Modeling CHAPTER OPENING PHOTO: Flow past a circular cylinder with Re ϭ rVDրm ϭ 2000: The pathlines of flow past any circular cylinder 1regardless of size, velocity, or fluid2 are as shown provided that the dimensionless parameter called the Reynolds number, Re, is equal to 2000. For other values of Re, the flow pattern will be different 1air bubbles in water2. (Photograph courtesy of ONERA, France.) Learning Objectives After completing this chapter, you should be able to: ■ apply the Buckingham pi theorem. ■ develop a set of dimensionless variables for a given flow situation. ■ discuss the use of dimensionless variables in data analysis. ■ apply the concepts of modeling and similitude to develop prediction equations. Experimentation and modeling are widely used techniques in fluid mechanics. V7.1 Real and model flies 332 Although many practical engineering problems involving fluid mechanics can be solved by using the equations and analytical procedures described in the preceding chapters, there remain a large number of problems that rely on experimentally obtained data for their solution. In fact, it is probably fair to say that very few problems involving real fluids can be solved by analysis alone. The solution to many problems is achieved through the use of a combination of theoretical and numerical analysis and experimental data. Thus, engineers working on fluid mechanics problems should be familiar with the experimental approach to these problems so that they can interpret and make use of data obtained by others, such as might appear in handbooks, or be able to plan and execute the necessary experiments in their own laboratories. In this chapter we consider some techniques and ideas that are important in the planning and execution of experiments, as well as in understanding and correlating data that may have been obtained by other experimenters. An obvious .