Waves Pt 2

Question 1

What happens when the wave “feels bottom”?

Answer 1

slows, and the accompanying** reduction** in the **wavelength results **in increased
height and steepness as the wave’s energy is condensed in a
smaller water volume.

Question 2

How do we calculate the steepness of the wave?

Answer 2

height/wavelength
(h/L)

Question 3

What happens to hight and wavelength when steepness increases?

Answer 3

Height Increases
Wavelength decreases

Question 4

What are breakers?

Answer 4

**shallow **water waves that become too steep at surface so they collapse

Question 5

How do breakers work?

Answer 5

particles at the wave’s crest move faster **toward **the shore resulting in the **curling **of the crest and the eventual breaking of the wave

Question 6

What happens if the wave steepness exceeds 1:7?

Answer 6

wave becomes** too steep **and the wave breaks

Question 7

What are the types of breaker waves?

Answer 7

Spilling
Plunging
Surging

Question 8

What are spilling breakers?

Answer 8

-lasts long and** continually breaking** and slowly loosing energy across the surf zone
-Most common
-Flat bottom

Question 9

What are plunging breakers?

Answer 9

-entire wave front steepens, curls and **collapses, relesing energy all at once.
-Occurs** in** steep bottoms**

Question 10

What are surging?

Answer 10

-Don’t break because it never reaches a critical wave **steepness.
(H/L)=1:7
-diminishes** in size and** looses momentum** as water
rushes up beach face
-occurs in** steep bottoms**

Question 11

What are stokes drift?

Answer 11

mass** transport** of water forward in
the direction of wave energy** movement.**

Question 12

How do stoke drifts occur?

Answer 12

Negligible in open ocean
Slow movement against coast causes nearshore
currents

Question 13

What is the general speed of a wave equation?

Answer 13

Celerity(Speed)=wavelength/time

Question 14

What happens to wavelgth as celerity is reduced

Answer 14

Wavelength is shortened

Question 15

What are shallow wave speed infuenced by?

Answer 15

influenced more by** depth**
than wavelength

Question 16

What are deep water waves influecnced by?

Answer 16

influenced by wavelength than depth

Question 17

What is dispersion?

Answer 17

Sorting of free waves as they move because** long period waves travel faster** than short period waves in deep water.

Question 18

What is deep water group speed?

Answer 18

when a group
of waves travels if generated by the same source in
deep water

Question 19

What is deepwater group speed equation?

Answer 19

Group wave speed=individual wave speed/2

Question 20

What is the shallow water speed equation?

Answer 20

celerity=3.13 * Sqare root of depth

Question 21

What is the deep water speed equation?

Answer 21

celerity=1.56*period

Question 22

What is gravitational acceleration?

Answer 22

9.81

Question 23

What happens to the old wave when a new wave is created?

Answer 23

Outer-most **wave’s energy **is **lost **in advancing the
wave form into undisturbed water

Question 24

What are deep wave interactions?

Answer 24

when wave groups
meet they pass through **each other** and** continue**

Question 25

What is constructive interference?

Answer 25

if **crests coincide**, they **reinforce** each other.

Question 26

What is destructive interference?

Answer 26

if **crests go against** each other, they **cancel** each other

Question 27

What is Wind Generated Wave Height?

Answer 27

controlled by s**peed, duration** and **fetch.**

Question 28

What latitude is best for big waves?

Answer 28

40-50 degrees

Question 29

When is there large fetch?

Answer 29

When there are **no landmasses**

Question 30

What are the traits of westerlies in 40-50 degree latitude?

Answer 30

**continuous** and **strong**

Question 31

What are episodic waves?

Answer 31

**abnormally high** wave that is **unrelated** to **local storm conditions**

Question 32

How can modeling rouge waves contribute to practical applications?

Answer 32

They can** help **in **establishment** of **mooring systems** that can **stablilize offshore platforms**

Question 33

What is a tsunami?

Answer 33

**long period sea wave **that is **produced** by an **earthquake, volcanic eruption, sediment slide** or** faulting**

Question 34

How long are tsunami wavelengths?

Answer 34

**very long** 100-200 km 60-120 miles

Question 35

How long are tsunami periods?

Answer 35

long (10-20 minutes)

Question 36

What type of wave are tsunamis?

Answer 36

**shallow water **waves. Because **depth** is **less** than **one-twentieth** the **wavelength**

Question 37

What are the 3 stages of tsunamis?

Answer 37

**G**eneration **P**ropogagnation **I**nundation

Question 38

What is generation?

Answer 38

The **point **of **source **of **energy** for tsunamis?

Question 40

what is propagation?

Answer 40

**movement** of **tsunami waves** through **space**

Question 41

What is Inundation?

Answer 41

**flooding **of **coastal systems**

Question 42

What is the equation to calculate the celerity of a tsunami?

Answer 42

celerity=3.13* squareroot of depth

Question 43

What is NOAA'S project DART?

Answer 43

**Deep Ocean assesment** and **reporting** of **tsunamis**

Question 44

What are internal waves?

Answer 44

**Waves** created **below** the **ocean's surface** at the** boundary between 2 destiny layers**

Question 45

What are sources of internal waves?

Answer 45

Low pressure systems depress pycnocline and when storm moves away will oscillate until reaching equilibrium. * **Speed **of **currents** **above** or **below pycnocline changes quickly. * Bathymetric changes.

Question 46

Wat are standing waves?

Answer 46

surface water oscillates vertically between fixed points called nodes but there is no progression.

Question 47

What happens to standing waves with 2 nodes?

Answer 47

A progressive wave directly reflected back on itself produces a standing wave, because the two waves—original and reflected —are moving at the same speed but in opposite directions.

Question 48

What do standing properties depend on?

Answer 48

geometry of the basin that the wave is in.

Question 49

What are examples of closed basins?

Answer 49

-teacup -lake -ocean basin

Question 50

What is the relationship between length of the basin and period?

Answer 50

when the length of the basin is increased the period of the wave is increased

Question 51

What is the relationship between depth of the basin and period?

Answer 51

when the depth of the water is increased the period is decreased

Question 52

Can standing waves occur in basins?

Answer 52

Yes, but the formula changes and the node is usually located at the opening of the basin to open water.

Question 53

What are examples of energy from waves?

Answer 53

(1) using the changing level of the water to lift an object, which can then do useful work because of its potential energy. (2) using the orbital motion of the water particles or the changing tilt of the sea surface to rock an object to and fro. (3) using rising water to compress air or water in a chamber