[L2]_PROPERTIES OF WIND

Question 1

ENGY-688

What is the Weibull density function formula?

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Answer 1

What is the Weibull density function formula?

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Question 2

ENGY-688

What is the Coriolis Force?

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Answer 2

Inertial force in rotating frames

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Question 3

ENGY-688

How does the Coriolis Force affect the northern hemisphere?

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Answer 3

Positive Acceleration

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Question 4

ENGY-688

What are ocean Gyres?

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Answer 4

Large currents in warm areas

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Question 5

ENGY-688

What is a Cyclone?

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Answer 5

Large scale rotating air mass

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Question 6

ENGY-688

How high above Earth’s surface does solar-heated air rise towards the poles?

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Answer 6

10 to 15 km

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Question 7

ENGY-688

How many Convection Cells are in each hemisphere?

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Answer 7

Three (3)

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Question 8

ENGY-688

Name the three (3) convection cells in each hemisphere

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Answer 8

Polar, Mid-Latitude, Hadley

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Question 9

ENGY-688

What is meso scale wind?

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Answer 9

Local topographic or thermally induced circulations (10-100km)

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Question 10

ENGY-688

What are jet streams?

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Answer 10

Type of wind streams

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Question 11

ENGY-688

What are geostrophic winds?

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Answer 11

Straight line flow winds

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Question 12

ENGY-688

What characterizes gradient winds?

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Answer 12

Non-geostrophic, parallel

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Question 13

ENGY-688

What is a key characteristic of the Normal Distribution?

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Answer 13

Symmetrical Function

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Question 14

ENGY-688

Why is Normal Distribution rarely used for wind modeling?

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Answer 14

Inaccurate Reflection

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Question 15

ENGY-688

What is the Rayleigh Distribution?

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Answer 15

A one parameter distribution

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Question 16

ENGY-688

What is easily computed from the Rayleigh Distribution?

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Answer 16

Mean Wind Speed

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Question 17

ENGY-688

What number of parameters does Weibull Distribution use?

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Answer 17

Two Parameters

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Question 18

ENGY-688

What does ‘k’ represent in Weibull distribution?

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Answer 18

Shape Factor

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Question 19

ENGY-688

What is the purpose and parameters does Weibull utilize?

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Answer 19

Site assessment of wind speed & Scale (c), shape (k)

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Question 20

ENGY-688

What effect does a higher k value have on a distribution curve?

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Answer 20

Narrower Shape, Lower Energy

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Question 21

ENGY-688

What is the common wind speed measurement interval?

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Answer 21

10-Min Average

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Question 22

ENGY-688

What is the typical value for k or alpha (shape factor)?

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Answer 22

2

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Question 23

ENGY-688

What is the formula for Power Density?

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Answer 23

PD = ½ * p * V³

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Question 24

ENGY-688

What affects Power Density?

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Answer 24

Air Density and Wind Speed

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Question 25

# ENGY-688 What is the air density at 15°C? ## Footnote [L2]

Answer 25

1.225 kg/m³ ## Footnote [L2]

Question 26

# ENGY-688 Who created the first wind scale? ## Footnote [L2]

Answer 26

Admiral Sir Francis Beaufort ## Footnote [L2]

Question 27

# ENGY-688 What is the purpose of the Beaufort wind scale? ## Footnote [L2]

Answer 27

Estimate wind speeds via visual identifiers ## Footnote [L2]

Question 28

# ENGY-688 What determines NREL Wind Power Class? ## Footnote [L2]

Answer 28

Power Density, Velocity, Hub Height ## Footnote [L2]

Question 29

# ENGY-688 What class is suitable for utility power applications? ## Footnote [L2]

Answer 29

Class 4 or Greater ## Footnote [L2]

Question 30

# ENGY-688 What is wind shear? ## Footnote [L2]

Answer 30

Change in wind speed in regards to altitude ## Footnote [L2]

Question 31

# ENGY-688 What generates microburst of wind shear typically? ## Footnote [L2]

Answer 31

Thunderstorms ## Footnote [L2]

Question 32

# ENGY-688 What are the stages of a microburst life cycle? ## Footnote [L2]

Answer 32

Formation, Impact, Dissipation ## Footnote [L2]

Question 33

# ENGY-688 What occurs during the formation stage of a microburst? ## Footnote [L2]

Answer 33

Evaporation and Precipitation Drag ## Footnote [L2]

Question 34

# ENGY-688 What is Low-level Wind Shear (LLWS)? ## Footnote [L2]

Answer 34

Longer Time-Frame of Velocity Changes ## Footnote [L2]

Question 35

# ENGY-688 How is LLWS quantified? ## Footnote [L2]

Answer 35

10-knots per 200-ft change ## Footnote [L2]

Question 36

# ENGY-688 What is the formula for the Power Law Profile? ## Footnote [L2]

Answer 36

v₂/v₁ = (h₂/h₁)γ ## Footnote [L2]

Question 37

# ENGY-688 How is z₀ related to the height of average roughness element? ## Footnote [L2]

Answer 37

1/30 of height ## Footnote [L2]

Question 38

# ENGY-688 What is the elevation range of the troposphere? ## Footnote [L2]

Answer 38

0 to 11 km ## Footnote [L2]

Question 39

# ENGY-688 What is the density difference at ground level vs 100m? ## Footnote [L2]

Answer 39

< 1% difference ## Footnote [L2]

Question 40

# ENGY-688 What does pd represent? ## Footnote [L2]

Answer 40

Partial pressure of dry air ## Footnote [L2]