fluid mechanics - lift

Question 1

what is the bernoulli principle

Answer 1

AN INCREASE IN THE SPEED OF A FLUID LEADS TO A DECREASE IN THE STATIC PRESSURE

relates to how a lift force is generated

Question 2

whats the difference between lift force in an upwards and downwards direction

Answer 2

up = longer air time, increased horizonatal displacement (discus)

down = forced towards the ground, increasing the amount of friction generated with the ground (cyclist)

Question 3

when is lift achieved

Answer 3

when both high and low air pressures act on an object

fast air that travels the futhest distance around the object has low pressure

slow air that travels the shortest distance around the object has high air pressure

wherever the low pressure is - thats which way the object/body goes

force is achieved when an object is tilted into the air flow

air moleculed that hit the leading abject travel around the object within the same time (over or under the object/body)

Question 4

evaluation of a discus’ lift - when going up (autonomous performer)

Answer 4

optimal 45 degree angle of attack

air molecules going over the top have furthest distance to travel

fast air = low pressure

air molecules going under have shortest distance to travel

slow air = high pressure

upwards lift created