WAVE TRANSFORMATION II (REFLECTION, BREAKING, REFORMING)

WAVE TRANSFORMATION IIREFLECTION, BREAKING, REFORMING Wave Transformation • reflection • breaking • reforming Wave Reflection... Partial Wave Reflection Modes in Closed and Open-Ended Ba

WAVE TRANSFORMATION II

(REFLECTION, BREAKING, REFORMING)

Wave Transformation

• reflection

• breaking

• reforming

Wave Reflection

2 2

cos

2

2 2

cos

2

i

i

r

r

 

    

 

    

cos cos 2

i

i r

       

            

Wave Reflection Incident and reflected wave:

Resulting wave (H r =H i):

2 2 cos cos

i

H

 

 

Water Surface and Particle Motion

Partial Wave

Reflection

Partial Wave

Reflection

Modes in Closed and Open-Ended Basins

Period of Oscillation: Closed Basin

2

2

Shallow Water Bodies

tanh

  

 

 

2B 1

j

l T



Alternative:

1, 2,

2

B

L

Period of Oscillation: Open-Ended Basin

1st harmonic:

4

B

L

l 

4l b T

gd



jth harmonic:

2 1

4

B

L

4 1

2 1

B j

l T





Reflection from Sloping Surfaces

r

i

H

H

 

Surf similarity parameter: tan

/

i o



 

Wave Reflection Coefficient

Correction Factors

Slope roughness

Multiple layers

Breaking Waves

Incipient Wave Breaking

Wave Breaking Criteria

Deep water: 0.142 1

7

o

o

H

Shallow water: b 0.78

b

H

Intermediate water:

max

2 0.142 tanh





Breaker Height Index

1

3.3( / )

b

H

Breaker Depth Index

H b /d bis a function of wave steepness and slope

Types of Wave Breaking

Breaker Types

Wave Reforming

Horikawa and Kuo Experiment

0.4

s

 

Stable wave height