Fluid Mechanics Review

These flashcards cover key concepts from fluid mechanics, focusing on properties of fluids, instruments, and fundamental principles.

What defines a fluid in terms of shear forces?

A fluid cannot remain at rest under action of any shear force.

At what temperature is the density of water maximized?

4°C.

What is the property of a fluid called when its molecules are attracted to each other?

Cohesion.

What is the term for the pressure the fluid exerts which is equal in all directions at a point only if it is at rest?

Hydrostatic pressure condition.

What contributes to the higher specific weight of sea water compared to pure water?

Dissolved salt.

What phenomenon causes liquid surfaces to contract to the smallest possible area?

Surface tension.

When does a liquid wet a solid surface?

When adhesion forces are greater than cohesion forces.

What instrument measures atmospheric pressure?

Barometer.

What is observed in a vertical submerged plane surface regarding pressure?

Pressure at every point does not remain the same.

How does the slope of the Hydraulic Gradient Line relate to the Energy Gradient Line in a pipe?

It is always smaller than that of the Energy Gradient Line for a pipe of uniform cross-section.

What describes the total pressure force on a submerged plane area?

It is equal to the area multiplied by the intensity of pressure at the centroid, only if the area is horizontal.

What is the buoyant force experienced by an immersed body?

It is equal to the weight of the fluid displaced by the body.

What causes the phenomenon known as water hammer in pipes?

It occurs when fluid is abruptly brought to rest by closing the valve.

What is the definition of viscosity?

It measures the fluid's resistance to shear stress.

In fluid mechanics, what does the term 'Reynolds number' indicate?

It is the ratio of inertia force to viscous force.

What is stated by Bernoulli's equation regarding energy in fluids?

It deals with the law of conservation of energy.

What is the relationship between the center of pressure and the center of gravity in submerged surfaces?

Center of pressure is always below the center of gravity.

What type of losses occur due to bends, sudden enlargements, or contractions in pipes?

Minor losses.

What condition do two pipe systems have to meet to be considered equivalent?

Head loss and discharge must be the same in both systems.