scanned by Fahid PDF created by AAZSwapnil A TextBook of Fluid Mechanics and Hydraulic Machines -Dr. R. K. Bansal Scanned by Fahid Converted to PDF. book is. I have kept the original concept throughout all editions and there is There is now a companion volume Solved Problems in Fluid Mechanics, which. This book was written as a textbook or guidebook on fluid mechanics for students or Fluid mechanics has hitherto been divided into 'hydraulics', dealing with.
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PDF | Fluid Mechanics 1 | ResearchGate, the professional network for scientists. Download full-text PDF. Citations (0). References (0). PDF | This book should be used by many different engineering disciplines. This book describes Download full-text PDF. Content uploaded by Bar-Meir, Genick, “Basics of Fluid Mechanics”, Last modiﬁed: Version March. 17, A Textbook of Fluid Mechanics. By R. K. Bansal. About this book · Shop for Books on Google Play. Browse the world's largest eBookstore and start reading today.
Geometrical similarity requires that the two systems have the same shape geometry , and dynamical similarity requries them to be operating in the same dynamic regime i. This will be expanded upon later. The number of dimensionless groups is invariably less than the number of original variables involved in the problem.
For example, a relation between two variables x vs. Relating four variables would obviously require many books or volumes.
Thus, reducing the number of variables from, say, four to two would dramatically simplify any problem involving these variables. It is important to realize that the process of dimensional analysis only replaces the set of original dimensional variables with an equivalent smaller set of dimensionless variables i.
However, dimensional analysis is a very powerful tool in that it can rovide a direct guide for 24 Chapter 2 experimental design and scale-up and for expressing operating relationships in the most general and useful form.
Another classic approach, which involves a more direct application of the law of conservation of dimensions, is attributed to Lord Rayleigh. Numerous variations on these methods have also been presented in the literature.
The one thing all of these methods have in common is that they require a knowledge of the variables and parameters that are important in the problem as a starting point.
This can be determined through common sense, logic, intuition, experience, or physical reasoning or by asking someone who is more experienced or knowledgeable. They can also be determined from a knowledge of the physical principles that govern the system e. These equations may be macroscopic or microscopic e.
Many problem statements, as well as solutions, involve assumptions that are implied but not stated. One should always be on the lookout for such implicit assumptions and try to identify them wherever possible, since they set corresponding limits on the applicability of the results.
The method we will use to illustrate the dimensional analysis process is one that involves a minimum of manipulations. It does require an initial knowledge of the variables and parameters that are important in the system and the dimensions of these variables. The objective of the process is to determine an appropriate set of dimensionless groups of these variables that can then be used in place of the original individual variables for the purpose of describing the behavior of the system.
Summary PDF Request permissions. PDF References Request permissions. PDF Request permissions. Tools Get online access For authors. Email or Customer ID. Forgot password? Old Password. New Password. Your password has been changed. This is because the fluid in this region is flowing slower than in the neck, and the pressure is increased over that in the neck, causing the vapor to become liquid again.
The phenomenon described in the above experiment is calledcavitation. Cavitation can strongly affect the performance of pumps and turbines, to the extent that in extreme cases it can cause mechanical damage to components and even stop the operation of the device. When gas bubbles formed by cavitation strike a solid surface the gas bubble tends to collapse, forming a liquid jet that in turn impacts the solid surface. This can result in erosion of the surface, thereby damaging pumps, turbines, and propellers, and eventually leading to the repair or replacement of parts.
Surface tension At the interface between a liquid and another liquid or a gas, the difference in the molecular structure of the two substances results in an imbalance of the molecular forces.
These forces can be quite strong, but they decay very rapidly with distance from the interface. From a continuum mechanical point of view, the interface behaves as if it were a very thin elastic film, or layer, with this film possessing elastic properties.
Familiar examples of this inter-facial effect are soap bubbles, the rise of oil in wicks and of water in soil, the wetting of paper, the breakup of jets, and the ability of small insects to walk on water. The amount of force per unit length necessary to deform this interfacial surface is called the surface tension, and is denoted by the Greek letter 0. Representative values are given in Appendix B for various fluids. Example 1. Lay a straight wire on top of the U so that it makes a right angle with the two legs of the U.