FLUID MECHANICS COMPREHENSIVE
EXAM SCRIPT VERIFIED QUESTIONS AND
SOLUTIONS GRADED APLUS
●● Solid vs fluid under shear
Answer: A solid can deform and stop at a fixed strain. A fluid keeps
deforming/flowing under shear stress.
●● Liquid
Answer: Has relatively constant volume, takes container shape, and can
form a free surface in a gravitational field.
●● Gas
Answer: Expands to fill available space and does not form a free surface
in an open container.
●● Viscous flow
Answer: Flow where frictional/viscous effects are significant, especially
near solid surfaces and in boundary layers.
●● Inviscid flow region
Answer: A flow region where viscous forces are negligible compared
with inertial or pressure forces, often away from walls.
, ●● Internal flow
Answer: Flow completely bounded by solid surfaces, such as pipe or
duct flow.
●● External flow
Answer: Flow over an object or surface, such as airflow over a ball,
plate, or vehicle.
●● Incompressible flow
Answer: Flow where density remains nearly constant, commonly liquid
flows and low-speed gas flows.
●● Compressible flow
Answer: Flow where density changes significantly, common for high-
speed gas flow.
●● Mach number
Answer: Ratio of flow speed to speed of sound. Ma < 1 subsonic, Ma =
1 sonic, Ma > 1 supersonic, Ma >> 1 hypersonic.
●● Laminar flow
Answer: Highly ordered fluid motion characterized by smooth layers,
usually at low Reynolds number or high viscosity.
EXAM SCRIPT VERIFIED QUESTIONS AND
SOLUTIONS GRADED APLUS
●● Solid vs fluid under shear
Answer: A solid can deform and stop at a fixed strain. A fluid keeps
deforming/flowing under shear stress.
●● Liquid
Answer: Has relatively constant volume, takes container shape, and can
form a free surface in a gravitational field.
●● Gas
Answer: Expands to fill available space and does not form a free surface
in an open container.
●● Viscous flow
Answer: Flow where frictional/viscous effects are significant, especially
near solid surfaces and in boundary layers.
●● Inviscid flow region
Answer: A flow region where viscous forces are negligible compared
with inertial or pressure forces, often away from walls.
, ●● Internal flow
Answer: Flow completely bounded by solid surfaces, such as pipe or
duct flow.
●● External flow
Answer: Flow over an object or surface, such as airflow over a ball,
plate, or vehicle.
●● Incompressible flow
Answer: Flow where density remains nearly constant, commonly liquid
flows and low-speed gas flows.
●● Compressible flow
Answer: Flow where density changes significantly, common for high-
speed gas flow.
●● Mach number
Answer: Ratio of flow speed to speed of sound. Ma < 1 subsonic, Ma =
1 sonic, Ma > 1 supersonic, Ma >> 1 hypersonic.
●● Laminar flow
Answer: Highly ordered fluid motion characterized by smooth layers,
usually at low Reynolds number or high viscosity.
