Thought Provoking Applications of Fluid Mechanics to Non-fluid Systems

Study of liquids and gases at rest or in motion comprise the most common and majority of applications of fluid mechanics. To a lesser extent principles of fluid mechanics have also been applied to non-fluid systems which can be modeled to mimic fluids. Examples of such systems include avalanche, land and debris slide, mudflow, hurricane, sand dune, airborne sand transport, microbial locomotion, and volcanic lava flow to name a few. Such systems are not commonly studied by fluid mechanists in natural sciences, i.e., mathematicians and physicists. This paper describes few applications of fluid mechanics to non-fluid systems in order to stimulate dialogue and discussion amongst pure fluid mechanists with a possibility of opening up new windows on fluid mechanics for research and teaching. Fluid mechanics principally deals with liquids and gases at rest or in motion referred to as fluid statics and fluid dynamics respectively. When applied to water these are termed as hydrostatics and hydrodynamics respectively. Fluid statics deals with designing of dam walls, dykes, flood gates, fluid storage tanks etc. Fluid dynamics has a much wider range of applications. The most common ones are the pipe flow problems with applications to chemical industry, crude oil pipe lines, oil refinery, water distribution network, sewerage disposal system and blood flow through arteries and capillaries to name a few. Width and length of pipes may vary over a broad range from few micron diameter and short length for application to blood flow to over one meter wide pipes and several hundred kilometers in length in case of a crude oil pipe line. The pipe line could be a single or multiple pipe system of varying widths. Other applications of fluid dynamics include open channel flow, ground water circulation and seepage, fluid discharge from underflow and sluice gates, river and harbour engineering, windmill and turbine engineering, atmospheric and water pollution transport, radiation transport from nuclear accidents, atmospherics dynamics, designing of streamlined automobiles, high speed trains, airplanes, and ocean liners to minimize drag and fuel consumption, etc. These applications involveonly either liquids or gases under varying initial and boundary conditions, and constitute the bulk of work by fluid