skg
18th April 2007, 09:18 AM
Dear friends,
I have a two dimensional wave energy density spectrum. I want to make a one dimensional spectrum out of this. How do I go about this?
Anyone having an idea or reference, please help me.
With regards,
skg.
skg
23rd April 2007, 07:22 AM
Hi,
Since I found out how to do it, I thought I will post it here.
In a two dimensional spectrum, you will have a list of frequencies(say 25 no.), list of directions(say 30 no.) and the energy values for each freq-dir combination (in this case 25 x 30 values). If the 2D spectrum is from a model (as output of the model, for example) which is the case with me, you will know the directional resolution of the model (in this case 360/30 = 12 deg). The directional resolution of spectral wave models will generally be theoretically equal to the directional spread (in the present case 12 deg).
Thus for the 2D spectrum, you have E=E(f,theta).
You have f1,f2,....f25 with you and theta_1,theta_2,....theta_30 with you. Also let 'dspr' be the directional spread(which is the same for all enrgies if your directional resolution of the model is constant).
The 1D spectrum is calculated by
E(fj) = dspr x {E(fj,theta_1) + E(fj,theta_2) + E(fj,theta_3) +....+E(fj,theta_30}
for j=1 to 25.
I found this to be working fine using 1D and 2D spectra obtained from model.
If anyone has a different approach, please let me know.
Regards...