Fluid is the state of matter which has the ability to flow. It takes the shape of the container and it deforms without applying any force unlike solids. Fluid mechanics is a branch of science which deals with fluid statics, fluid dynamics and properties of fluid. Fluid includes liquids, gases and plasmas but from civil engineering point of view, our scope includes liquids (mostly water) only. From engineering point of view, fluid mechanics includes manometry, hydrostatic forces, buoyancy and floatation, fluid kinematics, fluid dynamics, flow measurements, viscous flow of incompressible fluid, flow through pipes, vortex motion, boundary layer theory, laminar flow, turbulent flow, dimensional analysis, open channel flow, fluid machinery which further includes impact of jets, turbines, hydraulic pumps etc. We all know we have water scarcity and limited oil reserves as challenges which are to be dealt with effectively thus one should possess good knowledge about fluid mechanics in order to develop future technologies so as to use the available water in potable form or develop some new fuels by using the basic knowledge. Ships, submarines, boats, cruises etc. have to be suitably designed in order to be stable, to resist the forces and to provide comfort to passengers. Besides dead and live loads, the water load has to be considered appropriately so as to design a safe and a stable utility so one has to understand the basic properties of a fluid first. These properties include density, pressure, effect of temperature, viscosity etc. Since the change in density is negligible with respect to change in pressure so we assume water as an incompressible fluid. For stability, engineer should make sure that the metacenter should be above the center of gravity of the body. As the land resources are limited and observing the recent changes in climate due to global warming we should take the challenge of building structures in the water resources. For an instance, Burj Al Arab was built on an artificial island and it’s one of the most luxurious hotels of the world offering top class facilities. This was a very challenging project because it was built in the water so one has to account for dynamic effects of water with respect to daily and seasonal variations, executing such a massive project was itself a challenge without disturbing the marine life and the environment in general. This project also demanded a connecting link from the hotel to the mainland which was itself a challenge. As an engineer, one has to take all the factors in to account and fluid mechanics is one of them. A fluid can do magic and even destruction if not handled properly. You can witness the magic of fluid in fountains at some places where the turbulent flow is changed to laminar flow so as to get an aesthetic view. Destruction includes dam failures, floods etc. An engineer has the responsibility of improving lives by his/her innovative ideas, bringing new technologies, making things simpler. We build hydraulic structures like dams and a failure of such structures will be catastrophic. One has to understand fluid mechanics so as to consider all the possible factors including hydrodynamic pressure and also consider the effects of combination of factors. The main catch here is we should always know the context in which we are using the assumptions we make. One such example is elevated water tanks which are the lifelines of people’s life especially in the plain areas. Earlier, engineers only used to consider the hydrostatic forces of water in design but in the events of earthquake most of the tanks failed. This was due to the fact that dynamic effect of fluid was not considered in design. Thus a fluid may not behave same in all the conditions. Fluid machineries like turbines, pumps, hydraulic devices etc. utilizes the knowledge of basic properties of fluid, fundamental energy conservation laws, continuity equation and are vital resources of any nation’s economy which act as one of a measure to know how well a nation utilizes its water resources. Flow measurement devices like venture meter, orifice meter works on the principle of Bernoulli’s law, continuity equation and by using manometric fluid (mercury). Any country’s food requirements are fulfilled through agriculture but agriculture is a water intensive activity. Climate change has disturbed the monsoon arrival and departure significantly and farmers can’t depend on rainfall only. We need to develop artificial sources of water for agriculture like canals etc. Canals comes under open channel flow so a proper knowledge of this subject is required so as to ensure required discharge reaches to the farmers. More importantly, the fluid (water) has to travel long distance before it reaches to the fields so one has to study the flow profiles, calculate the losses etc. These losses has to be considered while designing a canal system so that sufficient quantity can be stored and released from the canal to ensure required discharge to the farmers. Thus, we can find the application of fluid mechanics in everyday life ranging from water to oil, boats to cruises etc. In fact around 71% of earth’s surface is covered with water and our infrastructure runs on oil so we must know about this basic state of matter to understand its significance in engineering.
Indian Institute of Technology Kanpur
National Institute of Technology Jamshedpur
INDIAN INSTITUTE OF TECHNOLOGY GUWAHATI