Air Flow

Question 1

What is the COANDA effect

Answer 1

When the flow of air encounters an object in its path it attaches itself to the objects surface and flows smoothly around it.

Question 2

2 conditions for the COANDA effect

Answer 2

The object is presented to at the airflow at aa slight angle.

The objects shape is relatively thin and smooth.(streamlined).

Question 3

Why does high pressure attract to low pressure

Answer 3

Air naturally goes from areas of high pressure to low pressure.Areas of depleted molecules need filling.

Question 4

What is a pressure gradient

Answer 4

Differences in pressure over a distance.

Question 5

What are streamlines/streamtube.

Answer 5

Streamlines are directions of flowing air .

A volume of air bounded by streamlines.

Question 6

What are the three types of flow

Answer 6

Laminar flow,
Turbulent flow,
Vortex flow

Question 7

What is laminar flow/streamlined flow

Answer 7

Laminar flow is when airflow moves from one direction to another in layered predicable flows. Smooth and predictable.

Question 8

Turbulent Flow

Answer 8

Air flowing past unstreamlined object breaks the streamlined flow resulting in an unsteady or turbulent flow. Forms a resistant to the streamlined flow that becomes drag.

Question 9

Vortex flow

Answer 9

Loses energy as it moves away from aircraft. Caused by aircraft itself from drag.

All 3 types of flow moving around aircraft at same time

Question 10

What is an ideal fluid

Answer 10

Has 2 key properties.
It is incompressible (density does not change))
Has no Viscosity.
Air is known as an ideal fluid.

Question 11

Equation of continuity in relation to mass flow

Answer 11

Mass can neither be destroyed nor created. Mass flow must remain the same (E.g when entering a streamtube)

Question 12

Relationship of area and Volume in a Venturi

Answer 12

A1XV1=A2XV2=A3XV3

When A2 decreases V2 increases
When A3 increases V3 decreases.

Question 13

Speed at which air density does not change

Answer 13

Upto 300knots

Question 14

Venturi Tube

Answer 14

Mass Flow entering must remain same exiting. At the throat of a Venturi flow rate increases as cross section area decreases.

Question 15

Relationship between airflow velocity and distance between streamlines

Answer 15

Spacing between stream lines reduces as flow velocity increases and increases when flow velocity decreases.

Question 16

Law of conservation of energy

Answer 16

Energy can neither be destroyed nor created only change from one form to another. Bernoulli’s theorem energy in a flow must remain constant.

Question 17

Bernoulli Principle

Answer 17

In the flow of an ideal fluid, the sum of pressure (static)and kinetic energy(dynamic pressure) must remain constant. Energy in a flow must remain constant.

Question 18

Converging Airflow (Venturi)

Answer 18

As tube converges flows speed increases. Dynamic pressure increases and static pressure decreases by
the same proportions.

In a diverging flow the opposite occurs.

SAME TOTAL PRESSURE MIST ME MAINTAINED.