Simpliest Notes on Fluid Mechanics 1

Fluids – refers to gases and liquids. It is a collection of molecules randomly arranged and held together by weak cohesive force.

Fluid Mechanics – study which deals with the properties of fluids and the interaction of fluids.

Fluid Groups

1. Fluid Statics – refers to the fluid that is at rest.
2. Fluid Dynamics – refers to the fluid that is at motion. 

Density (ρ) – defined as mass divided by volume. The unit is kg/m^3

 

ρ = mass/density

 

Specific Gravity (sp. Gr) – defined as Density of the Material divided by the density of the Water. This has no specific unit. And in experiments, Specific gravity is measured by a hydrometer.

Sp. Gr = density of the substance/density of water

  

Pressure – defined as force divided by Area. The unit is N/m^2 or Pa.

P = force/area

 

  Note:
       The bigger the Area, the smaller the Pressure. The smaller the area, the bigger the pressure.

Fluid Pressure – depend on the depth of the substance.

Gauge Pressure – excess above atmospheric pressure

P - Po = ρgy (Gauge Pressure)

Absolute Pressure – total pressure

P = + ρgy (Absolute Pressure)

Atmospheric Pressure – defined as Po = 1.013x10^5 N/m^2

 

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