How Calculate the Power of Wave’s

How Calculate the Power of Wave’s

The power generated by ocean wave can be determined approximately by assuming an ideal sinusoidal water wave of certain width which is show in the figure:

 The water level rise above and fall below the average sea level at site. The mass of water in one half sine that is above the average sea level is given by

            

ὠ  = wave width(m);

ρ = density of sea water (1000kg/m cube);

λ = wave length;

hὠ = wave height (trough to crest).

The height in the center of gravity of the mass in the wave crest is (hὠ/(4√2) ) above the sea level and that of the wave through below the average sea level. The total change in the potential energy during once cycle is given by

∆PE ὠ= mὠg = (∆hὠ )*(ὠ *  ρ )*(λ/2)  (g)*( hὠ/2√2) (hav)

           

            =g* ὠ* ρ *(λ/2)( hὠ/(2√2)) (2hὠ/(4√2)) 

This can be simplified to

∆PEὠ = (g* ὠ* ρ) ((hὠ*hὠ )/16)

The frequency of wave in the deep sea is ideally given by

Frequency = √(g/2πλ)

  So, the power developed by the ocean waves can be found from

Pὠ= ∆PE ὠ* frequency= (g* ὠ* ρ *λ*)((hὠ*hὠ )/16)( √g/2πλ )

   

       = (g*g* ὠ* ρ*hὠ*hὠ )/(32*f*π)

Thus a wave of ὠ = 1km width
 hὠ=5m    λ = 50m 

wave length has a water power capacity of 130 M. Even 2% conversion efficiency it can generate 2.6 MW of electrical power per km of costal line.

The power describe by the previous equation depends upon frequency f, which is random variable. The frequency distribution of the ocean wave show in the figure.

The energy comes from waves at the frequency in the range .1 to 1.0Hz. The energy becomes maximum at the frequency of .3Hz. The actual wave may have a long wave superimposed on the short wave from different direction. The total power from multiple- frequency wave may be approximated by superimposing the power from different frequency.