fluid dynamics

Question 1

what is laminar flow

Answer 1

streamlines are parallel and constant, not crossing (abrupt changes)

Question 2

what is turbulent flow

Answer 2

streamlines frequently cross, they from vortices, aka eddy currents, non continuous constantly changing

Question 3

what are the 4 critical factors of flow of liquids

Answer 3

1. flow speed
2. radius of tube
3. density
4. viscosity

Question 4

what can cause turbulent flow

Answer 4

an obstructing object

Question 5

what is viscosity

Answer 5

viscosity is internal friction or resistance between two layers (laminate) of a liquid which resists the flow of the liquid.

Question 6

greater the friction

Answer 6

greater the viscosity

Question 7

increase in temperature

Answer 7

decreases the viscosity

Question 8

what is stokes law

Answer 8

F = 6πηrv
resistance frictional force (drag) N = 6π x coefficient of viscosity in pascal seconds x radius of ball bearing x velocity of ball

Question 9

what are the conditions of stokes law

Answer 9

• object must be solid, smooth, spherical
• must be uniform density
• object must be larger than >0.001mm compared to fluid molecules
• the fluid must have laminar flow around the object
• the fluid must be homogenous (has the same properties at every point)

Question 10

how do you calculate upthrust

Answer 10

4/3πr^3 x ϱ x g(9.81)

Question 11

why is steel classed as a strong material

Answer 11

it has a large ultimate tensile stress value