Introduction To Fluid Mechanics

Terminology description:

Fluid mechanics is the branch of science that deals with behavior of fluids such as liquids, vapors and gases. Branch of fluid mechanics that deals with equilibrium state of fluids which has no shear stress is referred as fluid statistics. In case of static fluid, pressure remains same irrespective of magnitude of direction. Other branch of fluid mechanics that deals with part of the fluid which is in relative motion is referred as fluid dynamics. The understanding of fluid mechanics is essential for chemical engineer as most of the chemical operations are in fluid phase.

Fluids:

Fluid is referred as substance that can be distorted when a shear stress is applied over it. Rate of distortion is dependent on the magnitude of force and viscosity of fluid. No fluid can resist distortion continuously. Fluids are of two types namely compressible fluids and incompressible fluids. Compressible fluids are fluids whose density changes with temperature and pressure. Incompressible fluids are fluids whose density remains constant with change in temperature and pressure. In broad sagacity, fluids are of two types namely liquids and gases.  Generally liquids have more viscosity and density as molecules are very close together. Volumes of liquid remain constant and are independent of size, temperature and pressure. On the other hand, gases have less density and viscosity as the molecules are at distant. Both liquids and gases are extreme possibility cases of fluids.

Physical properties of fluids:

Physical properties of fluids are entirely dependent on particular fluid type. Following are physical properties of fluids.

• Relative density or density of fluid: It depends on individual molecule which occupies unit volume. Mass per unit volume is defined as density.
• Viscosity of fluid: Resistance of fluid to applied shear is referred as viscosity.
• Surface tension of fluid: Liquid which behaves like extended elastic membrane is referred as surface tension.

Questions:

• What are rheological properties of fluids?
• What are fluid dynamics and applications?
• What are types of fluids?