Lecture 4: Atmospheric Turbulence

Question 1

layers of the atmosphere

Answer 1

earth
troposphere
stratosphere
mesosphere
ionosphere

Question 2

at 50km, pressure has fallen to around 1 mbar so

Answer 2

little turbulence above this altitude

Question 3

temperature variations giving rise to optical effects of turbulence only significant in

Answer 3

the troposhere

Question 4

where is turbulence usually greatest

Answer 4

nearest the ground

Question 5

turbulence falls of exponentially with increasing altitude except

Answer 5

for peak that occurs at the tropopause

Question 6

Peak that occurs at the tropopause is due to

Answer 6

wind shear

Question 7

wind shear gives rise to

Answer 7

kelvin-helmholtz instabilities

Question 8

kolmogorov model - energy added to fluid in the form of

Answer 8

large scale disturbances

Question 9

kolmogorov model - eddies or vortices generated on

Answer 9

outer scale
L0

spawns cascade on smaller eddies

Question 10

kolmogorov model - turbulence dies away at

Answer 10

inner scale
l0

Question 11

kolmogorov model - kinetic energy dissipated by

Answer 11

viscosity

Question 12

kolmogorov model - outer scale L0 is typically

Answer 12

10m

Question 13

kolmogorov model - inner scale l0 is typically

Answer 13

few mm

Question 14

kolmogorov model - stable state…

Answer 14

rate of input of turbulent energy =
rate of viscous dissipation

Question 15

kolmogorov model - fluctuations in velocity are governed only by

Answer 15

scale, l , and the rate of energy input/dissipation per unit mass, epsilon

Question 16

kolmogorov model - epsilon

Answer 16

rate of energy per unit mass

(units of J/s/kg)