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3D Directional Spectrum

MikeArmstrong
4-Participant

3D Directional Spectrum

I am struggling to plot the 3D directional spectrum (formula shown below) in the attached worksheet. I have plotted the 2D spectrum but need to display the 3D spectrum with theta ranging from zero to 360deg.

Clipboard01.jpg

Any help with be much appreciated.

Mike

11 REPLIES 11

Sorry it should read 2D. I am looking for something similar to below.

Clipboard02.jpg

Mike

You can do something like that with CreateMesh

Thanks Fred that is very helpful. It's not exactly what I'm looking for but very close. I'll come back with a little more information.

Mike

Mike Armstrong wrote:

I am struggling to plot the 3D directional spectrum (formula shown below) in the attached worksheet. I have plotted the 2D spectrum but need to display the 3D spectrum with theta ranging from zero to 360deg.

Why should theta range up to 360°? The function D.w in your worksheet would return zero for theta greater than 90°.

Attached a try without create mesh using the quickplot facility. You simply have to avoid that the first parameter is zero, so in my plot its running from 10^-10 up to 2.

The function however seems not to resemble the one from the Excel plot.

Cheers Werner, that's a little closer. I believe it is similar but only displaying half the wave cycle.

The spectral density values seems a little low if I'm honest as the formula might not be fully correct. I'll have to check again in work tomorrow. I have just had a little play with the plot settings and it looks closer to the Excel plot.

Mike

Running theta from -90 to +90 will give the full spectrum, but it looks like it has a rather sharp edge!?

spec1.png

That does looks better again. Could you upload the worksheet please. I cannot seem to replicate the graph you uploaded.

Mike

Here you are

Very nice, cheers for the help.

Mike

You are welcome.

Just notice that your spectrum is not symmetrical around theta=0, so you won't get even the half for positive values of theta.!?

spectrum1.png

I also noticed that, thanks Werner.

I have only had a little time to continue working on this, so it's not finished. Should have the finished worksheet shortly.

Mike

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