fluid mechanics Flashcards
when an aerofoil is travelling what is the difference in velocity between the 2 directions the air will take
the air that travels over the top of the aerofoil will travel with higher velocity and underneath will have lower velocity
when an aerofoil is travelling what is the difference in pressure between the 2 directions the air will take
the air travelling over the top with greater velocity will create an area with lower pressure and underneath where the air is travelling with lower velocity there will be higher pressure
how does a discuss get upwards lift
because of the bernoulli principle the higher pressure underneath will cause the discuss to lift because the air will want to move to the lower pressure area
definition of drag force
it is the resistance force experienced when travelling through a fluid environment and acts in the opposite direction
has a negative effect on velocity
it is a combination of air resistance and friction
what are the two types of drag
surface and form
what is surface drag and what is it also known as
relates to the friction between the surface of of the object and the fluid environment
skin drag
what is a fluid environment
liquid or gas, water or air
how can swimmers and cyclists reduce their surface drag
by wearing skin tight clothing and shaving their body hair
what is form drag
refers to the impact of the fluid environment on the object, relating to how streamlined the object is
how do cyclists reduce their form drag
drafting which is changing the leader, Belgian tourniquets
how do swimmers and cyclist reduce their form drag
by creating the smallest possible cross sectional front area
how can sprinters reduce their form drag
by keeping their arms close to their body and keeping their hands flat
what is laminar flow
when there is no turbulence behind the object
what is vortex flow
when there is turbulence behind an object which acts to pull back the performer
which type of flow is good which is bad
laminar flow is good and vortex flow is bad
