Lecture 26 - Fluid Dynamics Part 1 Flashcards
what is a fluid
any substance that tends to flow or continuous deform when acted on by a shear force
what is relative velocity
is the vector subtraction of the body’s velocity from that of the fluid
how to calculate relative velocity
if its head wind subtract the wind from the velocity
if its tail wind, add the velocity of the wind to the velocity of the person
laminar flow is characterised by
smooth layers of fluid molecules flowing parallel to one another
turbulent flow is characterised by
mixing of adjacent layers of fluid
turbulence of fluid may be affected by
shape, roughness and speed of the body
density is defined as (and what is the unit )
density (p) is defined as mass/ volume
what is the specific weight and its unit
specific weight (y) is the ratio of weight to volume
the denser and heavier the fluid medium surrounding a body, the …
greater the magnitude of the forces the fluid exerts on the body
what is viscosity
the internal resistance of a fluid to flow
the greater the extent to which a fluid resists flow under an applied force, the …
more viscous the fluid is
what happens to the viscosity of a gas when temperature increases
gas viscosity increases
what happens to the viscosity of a liquid when temperature increases
liquid viscosity decreases
what is buoyancy
fluid force acting upward is equal to the weight of the fluid displaced by the body
what is archimedes principle
physical law stating that the buoyant force acting on a body is equal to the weight of the fluid displaced by the body
