ch15outline

PED 351 BIOMECHANICS LECTURE OUTLINE
Chapter 15 Human Movement in a Fluid Medium

Chapter 15 Key Terms:

angle of attack angle between the longitudinal axis of a body and the direction of the fluid flow

Archimedes' principle physical law stating the buoyant force acting on a body is equal to the weight of the fluid displaced by the body

Bernoulli principle an expression of the inverse relationship between relative velocity and relative pressure in a fluid flow

boundary layer layer of fluid immediately adjacent to a body

center of volume point around which a body's volume is equally distributed and at which the buoyant force acts

coefficient of drag unitless number that is an index of a body's ability to generate fluid resistance

coefficient of lift unitless number that is an index of a body's ability to generate lift

fluid substance that flows when subjected to a shear stress

foil shape capable of generating lift in the presence of a fluid flow

form drag, profile drag, pressure drag resistance created by a pressure differential between the lead and rear sides of body moving through a fluid

laminar flow flow characterized by smooth, parallel layers of fluid

lift force acting on a body in a fluid in a direction perpendicular to the fluid flow

lift/drag ratio the magnitude of the lift force divided by the magnitude of the total drag force acting on a body at a given time

Magnus effect deviation in the trajectory of a spinning object toward the direction of spin resulting from the Magnus force

Magnus force lift force created by spin

propulsive drag force acting in the direction of a body's motion

propulsive drag theory theory attributing propulsion in swimming to propulsive drag on the swimmer

propulsive lift theory theory attributing propulsion in swimming at least partially to lift acting on the swimmer

relative velocity velocity of a body with respect to the velocity of something else, such as the surrounding fluid

skin friction, surface drag, viscous drag resistance derived from friction between adjacent layers of fluid near a body moving through the fluid

theoretical square law drag increases approximately with the square of velocity when relative velocity is low

turbulent flow flow characterized by mixing of adjacent fluid layers

wave drag resistance created by the generation of waves at the interface between two different fluids, such as air and water

angle of attack	angle between the longitudinal axis of a body and the direction of the fluid flow
Archimedes' principle	physical law stating the buoyant force acting on a body is equal to the weight of the fluid displaced by the body
Bernoulli principle	an expression of the inverse relationship between relative velocity and relative pressure in a fluid flow
boundary layer	layer of fluid immediately adjacent to a body
center of volume	point around which a body's volume is equally distributed and at which the buoyant force acts
coefficient of drag	unitless number that is an index of a body's ability to generate fluid resistance
coefficient of lift	unitless number that is an index of a body's ability to generate lift
fluid	substance that flows when subjected to a shear stress
foil	shape capable of generating lift in the presence of a fluid flow
form drag, profile drag, pressure drag	resistance created by a pressure differential between the lead and rear sides of body moving through a fluid
laminar flow	flow characterized by smooth, parallel layers of fluid
lift	force acting on a body in a fluid in a direction perpendicular to the fluid flow
lift/drag ratio	the magnitude of the lift force divided by the magnitude of the total drag force acting on a body at a given time
Magnus effect	deviation in the trajectory of a spinning object toward the direction of spin resulting from the Magnus force
Magnus force	lift force created by spin
propulsive drag	force acting in the direction of a body's motion
propulsive drag theory	theory attributing propulsion in swimming to propulsive drag on the swimmer
propulsive lift theory	theory attributing propulsion in swimming at least partially to lift acting on the swimmer
relative velocity	velocity of a body with respect to the velocity of something else, such as the surrounding fluid
skin friction, surface drag, viscous drag	resistance derived from friction between adjacent layers of fluid near a body moving through the fluid
theoretical square law	drag increases approximately with the square of velocity when relative velocity is low
turbulent flow	flow characterized by mixing of adjacent fluid layers
wave drag	resistance created by the generation of waves at the interface between two different fluids, such as air and water