FLUID MECHANICS CERTIFICATION
EVALUATION EXAMS SET FULL QUESTIONS
AND COMPLETE SOLUTION
●● strain rate
Answer: change in strain (deformation) of a material with respect to time
(constant shear force is applied, a solid eventually stops deforming at
some fixed strain angle, whereas a fluid never stops deforming and
approaches a constant rate of strain)
●● strain
Answer: number that describes relative deformation or change in shape
and size of elastic, plastic, and fluid materials under applied forces.
●● velocity gradient
Answer: a measure of how the velocity of a fluid changes between
different points within the fluid
●● liquid
Answer: groups of molecules can move relative to each other, but the
volume remains relatively constant because of the strong cohesive forces
between the molecules. As a result, a liquid takes the shape of the
container it is in, and it forms a free surface in a larger container.
, ●● gas
Answer: expands until it encounters the walls of the container and fills
the entire available space. This is because the gas molecules are widely
spaced, and the cohesive forces between them are very small. Unlike
liquids, a gas in an open container cannot form a free surface.
●● critical temperature
Answer: highest temperature at which a gas can be changed into a liquid
●● vapor
Answer: usually implies that the current phase is not far from a state of
condensation
●● no-slip condition
Answer: as a fluid flows across a solid surface, the fluid motion comes
to a complete stop at the surface and assumes a zero velocity relative to
the surface. while the remaining fluid flows past by continually changing
shape.
●● boundary layer
Answer: the flow region adjacent to the wall in which the viscous effects
(and thus the velocity gradients) are significant. (thin layer of a flowing
gas or liquid in contact with a surface)
EVALUATION EXAMS SET FULL QUESTIONS
AND COMPLETE SOLUTION
●● strain rate
Answer: change in strain (deformation) of a material with respect to time
(constant shear force is applied, a solid eventually stops deforming at
some fixed strain angle, whereas a fluid never stops deforming and
approaches a constant rate of strain)
●● strain
Answer: number that describes relative deformation or change in shape
and size of elastic, plastic, and fluid materials under applied forces.
●● velocity gradient
Answer: a measure of how the velocity of a fluid changes between
different points within the fluid
●● liquid
Answer: groups of molecules can move relative to each other, but the
volume remains relatively constant because of the strong cohesive forces
between the molecules. As a result, a liquid takes the shape of the
container it is in, and it forms a free surface in a larger container.
, ●● gas
Answer: expands until it encounters the walls of the container and fills
the entire available space. This is because the gas molecules are widely
spaced, and the cohesive forces between them are very small. Unlike
liquids, a gas in an open container cannot form a free surface.
●● critical temperature
Answer: highest temperature at which a gas can be changed into a liquid
●● vapor
Answer: usually implies that the current phase is not far from a state of
condensation
●● no-slip condition
Answer: as a fluid flows across a solid surface, the fluid motion comes
to a complete stop at the surface and assumes a zero velocity relative to
the surface. while the remaining fluid flows past by continually changing
shape.
●● boundary layer
Answer: the flow region adjacent to the wall in which the viscous effects
(and thus the velocity gradients) are significant. (thin layer of a flowing
gas or liquid in contact with a surface)
