H7

Question 1

wave

Answer 1

displacement of energy, not of medium (water stays on more or less the same place)

Question 2

parts of a wave (4)

Answer 2

1. wave height (golfhoogte)
2. crest (golftop)
3. wave length (golflengte)
4. trough (golfdal)

Question 3

wave period

Answer 3

time between two consecutive crests that pass by the same point (one wave length)

Question 4

7 types of waves (ordered from lowest to greatest in wave period)

Answer 4

1. capillary waves (capillaire)
2. chop waves (kalme golven)
3. swell waves (surfgolven)
4. seiches (meteotsunami)
5. tsunamies (tsunami’s)
6. tidal waves (getijdengolven)
7. internal wave (onderwater golven)

Question 5

the size and type of wave is dependent on:

Answer 5

1. wind speed
2. duration of the wind
3. fetch (strijklengte)
4. initial situation

Question 6

what does higher wind speed mean?

Answer 6

the longer the wave length, wave period and height

Question 7

be each windspeed is there a:

Answer 7

1. average wave height, length and period
2. significant height
3. determinant for damage on e.g. ships and erosion of coast lines

Question 8

wave height

Answer 8

the significant wave height is the average wave height, from trough to crest, of the highest 33% (1/3) of the wave height during a timed interval. The significant wave height is, as a rule of thumb, the height that people perceive visually.

Question 9

progressive waves (lopende golven)

Answer 9

energy moves, water mass moves little/does not move

Question 10

how do water molecules move in the movement of waves?

Answer 10

vertical, circle forming motion (orbital motion).

1. diameter of the circle increases with wave size
2. diameter of the circle decreases with depth
3. decreasing diameter of the circle (orbital motion) with increasing distance under the water surface.
4. under 0,5L (the half wave length) there is no movement more of the wave

Question 11

is there net water transport?

Answer 11

1. orbits are not always closed, therefore, there is net water transport
2. in open ocean this is negligible, but in deep water it has more effect

Question 12

what happens to the orbits if the water is deeper than the half wave length (wave base)?

Answer 12

the orbits are circular and there is no influence on the bottle of the wave or otherwise

Question 13

what happens to the orbits if the water is shallower than the half wave length (wave base)?

Answer 13

the orbits are elliptical and there is an influence on the bottom of the wave and otherwise.

Question 14

calculation for the speed of a wave

Answer 14

C = L/T

C= celerite, or wave speed 
L= wave length
T= wave period

Question 15

what is wave speed dependent on?

Answer 15

wave length, wave period and wave type (deep wave, shallow wave, medium wave)

Question 16

how do waves exist in new ocean?

Answer 16

many waves, chaotic sea

Question 17

how do waves exist in living ocean?

Answer 17

deinende waves, regular

Question 18

how do waves exist in a dying ocean?

Answer 18

breaking waves

Question 19

what happens during the breaking of waves to wave length?

Answer 19

decreases

Question 20

what happens during the breaking of waves to wave speed?

Answer 20

decreases

Question 21

what happens during the breaking of waves to the wave height

Answer 21

increases

Question 22

do longer waves travel faster than shorter waves? why or why not?

Answer 22

yes. wave speed (celerity) increases as soon as wave length increases. Therefore, longer waves are faster than shorter waves

Question 23

waves in deep water

Answer 23

how deeper the water, the bigger the interaction between waves and the bottom. By increase of the depth, is there also and increase of the wave speed and wave length. wave heigh increases. If the H/L is greater than or equal to 1/7, then the wave becomes unstable and breaks.

Question 24

how to calculate wave speed in deep water

Answer 24

C = square root of gd

G=gravitational acceleration (zwaartekrachtversnelling)
D=water depth

Question 25

Refraction

Answer 25

Reflection involves a change in direction of waves when they bounce off a barrier. Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or the bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves.

Question 26

types of breaking waves

Answer 26

1. spilling breaker
2. plunging breaker
3. surging breaker

Question 27

standing wave

Answer 27

1. movement is not horizontal
2. move back and forth around a fixed point called a node
3. a standing wave in a lake, harbour or estuary is a seiche (meteotsunami)

Question 28

underwater waves originating from pycnocline:

Answer 28

1. contact between water layers of different densities

2. comparable with contact between water layer and air layer

Question 29

how are underwater waves measured?

Answer 29

the course of temp of the water indicates extreme underwater waves

Question 30

tsunamies

Answer 30

1. tsunamies are also called flood waves
2. the occur through, for example, volcanic eruptions and earthquakes
3. they are not related to tides

Question 31

process of tsunami creation:

Answer 31

1. start with low wave, long wave period and long wave lengths
2. in the open ocean, celerity is 760km/hour
3. wave heigh starts low (around 2m) and grows to greater than 10m