Basics

Fluid mechanics studies liquid and gas substances. It studies the behavior of a fluid(liquid or gas) either at rest or in motion. A fluid is a substance that continuously deforms when a tangential(shear) force acts on the surface of the substance. This is why a solid is not a fluid because it may deform when a shear force is applied but will not continuously deform.

Some fundamental law associated with fluid mechanics include: Newton's laws, the first and second law of thermodynamics, and conservation of mass.

Characteristics/Measurements of fluids:

• Density: mass per unit volume. Change in temperature/pressure have little effect on the density of liquid but a great effect on the density of gas.
• Specific Weight: weight per unit volume. It is the product of density multiplied by the acceleration of gravity.
• Specific Gravity: the ratio of the density of the substance to the density of water at 4 degrees C.

Ideal Gas Law: relates the pressure, temperature, and density of a gas because gases are highly compressible (unlike liquids). Any change in the variables will directly effect the others through the ideal gas equation: density = pressure / R*temperature
where R is the gas constant(different for every element) which can be found in tables.

Characteristics of fluid flow are size(size of pipe), velocity, and pressure.


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