Basic Fluid Properties
Fluids, which include both liquids and gases, are fundamental in fluid mechanics, where their behavior is analyzed based on key properties that influence motion, pressure, and flow dynamics. These properties determine how fluids respond to external forces and interact with their surroundings in various engineering applications.
Density
Density is the ratio of mass of fluid and its volume.
Where:
The density of water is 1.94 slug/ft^3 or 1000 kg/m^3
Example
The glycerin has a mass of 1200 kg and a volume of 0.952 cu.m. Find its density?
Specific Volume
is the reciprocal of the density.
Specific Weight
weight of the fluid per unit volume.
Where:
Units: 
Example
Specific Gravity of an oil is 0.82. Determine its specific weight
Specific Gravity
ratio of density of a substance to density of water.
where:
Bulk Modulus of Elasticity
Materials resistance to compression
Example
A liquid compressed in a cylinder has a volume of 1000 cu.m at 
and a volume of 
at 
. What is its bulk modulus of elasticity?
Compressibility
reciprocal of the bulk modulus. It measures how much a material decreases in volume when subjected to pressure.
Units: 
Example
If the Bulk Modulus of Water is 2.2 GPa. What is its coefficient of Compressibility?
Viscosity
Viscosity is defined as the fluid’s resistance to flow.
Units: poise or 0.1 Pa-s
Surface Tension
The force responsible for the tension that acts along its surface and arises from the attractive forces between the liquid’s molecules. The strength of this force per unit length is known as surface tension.
Capillary Action
is when liquid rise or fall through narrow spaces without external forces.
References
J. D. Anderson Modern Compressible Flow with Historical Perspective, 3rd ed. New York: McGraw-Hill, 2003.
F L U I D M E C H A N I C S FUNDAMENTALS AND APPLICATIONS Third Edition. (n.d.). https://engineeringbookslibrary.wordpress.com/wp-content/uploads/2019/03/fluid-mechanics-fundamentals-and-applications-3rd-edition-cengel-and-cimbala-2014.pdf
