FLUID DYNAMICS

Question 1

-Reynolds Number

Answer 1

Dimensionless indicator predicting laminar or turbulent flow (depends on velocity, pipe diameter & viscosity).

Question 2

Bernoulli’s Equation

Answer 2

Energy conservation relation between pressure, velocity, and elevation in fluid flow.

Question 3

Laminar Flow

Answer 3

Smooth, orderly flow; Reynolds number < 2000.

Question 4

Turbulent Flow

Answer 4

Chaotic, mixed flow; Reynolds number > 4000.

Question 5

Viscosity

Answer 5

Fluid resistance to deformation; thicker fluid = higher viscosity.

Question 6

Boundary Layer

Answer 6

Thin region near a solid surface where velocity changes from zero to free stream.

Question 7

Cavitation

Answer 7

Vapor bubble formation due to low pressure; causes pump/turbine damage.

Question 8

Head Loss

Answer 8

Loss of energy due to pipe friction & fittings.

Question 9

Continuity Equation

Answer 9

Mass flow must remain constant: A₁V₁ = A₂V₂.

Question 10

Darcy-Weisbach Equation

Answer 10

Computes head loss due to friction in pipes.

Question 11

Static Pressure

Answer 11

Pressure acting perpendicular to flow direction.

Question 12

Dynamic Pressure

Answer 12

Pressure due to fluid motion: ½ρV².

Question 13

Volumetric Flow Rate

Answer 13

Volume per unit time (m³/s).

Question 14

Mass Flow Rate

Answer 14

Mass per unit time (kg/s).

Question 15

Pump Head

Answer 15

Height a pump can raise water — indicator of pump performance.

Question 16

Specific Speed (Pump)

Answer 16

Classifies pump type & performance range.

Question 17

Affinity Laws

Answer 17

Pump performance changes with speed, flow, and impeller diameter.

Question 18

Water Hammer

Answer 18

Pressure surge due to sudden change in flow direction/velocity.

Question 19

Venturi Meter

Answer 19

Flow measurement device using constriction + pressure drop.

Question 20

Orifice Plate

Answer 20

Flow measurement device using a plate with a hole to produce pressure drop.

Question 21

Drag Force

Answer 21

Force resisting motion due to fluid contact.

Question 22

Lift Force

Answer 22

Perpendicular force from flowing fluid; used in blades/turbines.

Question 23

NPSH (Net Positive Suction Head)

Answer 23

Minimum suction pressure to prevent cavitation.

Question 24

Friction Factor

Answer 24

Resistance measure used in pipe flow head loss calculations.

Question 25

Hydraulic Diameter

Answer 25

Equivalent diameter for non-circular ducts: 4A/P.

Question 26

Flow Velocity Profile

Answer 26

Illustration of how velocity varies across pipe section.

Question 27

Compressible Flow

Answer 27

Density changes significantly with pressure (common in gases).

Question 28

Incompressible Flow

Answer 28

Density nearly constant (assumed for liquids).

Question 29

Surge (Compressors)

Answer 29

Oscillating unstable flow leading to damage.

Question 30

Slip (Centrifugal Pumps)

Answer 30

Difference between impeller theoretical and actual flow, reducing efficiency.