Lecture 27 - Fluid Dynamics Part 2 Flashcards
what is drag
a force caused by the dynamic action of a fluid that acts in the direction of a free stream fluid flow
generally, drag is a what force and what does this cause
drag is a resistance force that slows down the motion of a body moving through a fluid
how to calculate drag
FD = 1/2 CDpApV^2
what is the coefficient of drag
unitless number that is an index of a body’s ability to generate fluid resistance
what are the three types of drag
form, surface and wave drag
what is viscous drag
surface drag
what is the boundary layer
layer of fluid immediately adjacent to a body
what is form drag
resistance created by a pressure differential between the lead and rear sides of a body moving through a fluid
whenever a pressure differential exists, a force is ….
directed from the region of high pressure to the region of low pressure
what are factors that affect form drag
- shape (frontal surface area)
- speed
- surface roughness
what is wave drag
resistance created by generation of waves at the interface between two different fluids, such as air and water
what affects wave drag
velocity
up and down motion
