Difference between revisions of "Shoaling"
From Coastal Wiki
Dronkers J (talk  contribs) 

(3 intermediate revisions by the same user not shown)  
Line 1:  Line 1:  
{{  {{  
Definitiontitle=Shoaling  Definitiontitle=Shoaling  
−  definition= Shoaling is the deformation of the  +  definition= Shoaling is the deformation of incident waves on the lower [[shoreface]] that starts when the water depth becomes less than about half of the [[wavelength]], causing the waves to become steeper: increase in amplitude and decrease in wavelength. }} 
−  +  
+  
+  
+  ==Notes==  
+  *Wave amplification is due to (approximate) continuity of the '''wave energy flux''' <math>F=c_g E</math> seaward of the [[surf zone]], where <math>E = \frac{1}{8} \rho g H^2</math> is the wave energy and <math>c_g</math> the [[wave group]] propagation speed. The landward decrease of the wave group propagation speed (<math>c_g \approx \sqrt{gh}</math> in shallow water of depth <math>h</math>) results in a landward increase of <math>E</math>, thus in a landward increase of wave height <math>H</math>. See: [[Shallowwater wave theory]] for a more detailed treatment.  
+  *Wave propagation in the shoaling zone has a strongly nonlinear character because the wave height is no longer negligible compared to the water depth. This produces wave asymmetry, with the wave orbital velocity being greater in the onshore than offshore direction and the offshoretoonshore orbital acceleration being greater than the onshoretooffshore acceleration.  
+  *Wave shoaling precedes wave breaking on the upper [[shoreface]] when the wave steepness exceeds a critical limit.  
+  
+  
+  [[Image:Shoaling.jpgthumb400pxcenterShoaling wave.]]  
+  
−  
−  
==See also==  ==See also==  
−  * [[  +  * [[Shallowwater wave theory]] 
+  * [[Breaker index]]  
* [[Wave transformation]]  * [[Wave transformation]] 
Latest revision as of 12:50, 12 April 2022
Definition of Shoaling:
Shoaling is the deformation of incident waves on the lower shoreface that starts when the water depth becomes less than about half of the wavelength, causing the waves to become steeper: increase in amplitude and decrease in wavelength.
This is the common definition for Shoaling, other definitions can be discussed in the article

Notes
 Wave amplification is due to (approximate) continuity of the wave energy flux [math]F=c_g E[/math] seaward of the surf zone, where [math]E = \frac{1}{8} \rho g H^2[/math] is the wave energy and [math]c_g[/math] the wave group propagation speed. The landward decrease of the wave group propagation speed ([math]c_g \approx \sqrt{gh}[/math] in shallow water of depth [math]h[/math]) results in a landward increase of [math]E[/math], thus in a landward increase of wave height [math]H[/math]. See: Shallowwater wave theory for a more detailed treatment.
 Wave propagation in the shoaling zone has a strongly nonlinear character because the wave height is no longer negligible compared to the water depth. This produces wave asymmetry, with the wave orbital velocity being greater in the onshore than offshore direction and the offshoretoonshore orbital acceleration being greater than the onshoretooffshore acceleration.
 Wave shoaling precedes wave breaking on the upper shoreface when the wave steepness exceeds a critical limit.