Page 32 - ebook fluid mechanics_finalize

FLUID MECHANICS

CHAPTER 3 : FLUID STATICS

3.0 FLUID STATICS

Fluid static is the study of pressures throughout a fluid at rest and the pressure

forces on an infinite surface. Fluid statics is the part of fluid mechanics that deals
with fluids when there is no relative motion between the fluid particles. Typically this

includes two situations: when the fluid is at rest and when it moves like a rigid solid.

The general rule applies to fluid at rest:

• No shears stress /force acting on it.

• Any force between the fluid and the boundary must be acting at right angles to the

boundary (normal to the surface).

F
F

Figure 3.1 : Pressure forces normal to the boundary

NOTE : This statement is also true for curved surfaces, in this case the force acting at

any point is normal to the surface at that point.

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