Turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Mute
- Printer Friendly Page

Frutis

Member

04-08-2021 11:15 AM - edited 04-08-2021 11:17 AM

Options

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report to a Moderator

Good morning,

I have a question about FFT in Diadem. The output of FTT function is frequency (f) in Hz, is there any way to get the output in angular frequency **ω**? The equation would be **ω **= 2*pi*f where f is the frequency.

Furthermore is there any way to plot the FTT output in wavenumber (k) domain provided that

k*U = 2*pi*f = **ω**

where U is the mean velocity that I can easily calculate?

So that would be 3 functions:

AplitudePeak(frequency) <-> AmplitudePeak(angular frequency) <-> AmplitudePeak(Wavenumber)

I am new to signal processing and this is for turbulence spectra analysis from a velocity vs time signal from hot wire if this has any meaning.

Thank you in advance

Walter_Rick

Active Participant

04-15-2021 01:17 AM

- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report to a Moderator

Hi Frutis,

In DIAdem there is no parameter for the FFT function to do this, but it is easy to calculate it afterwards.

For this you can use the Calculator with this equation:

ch("[1]/angular frequency")= 2 * Pi * ch("[1]/Frequency")

or this in a script:

Call Calculate("ch(""[1]/angular frequency"")= 2 * Pi * ch(""[1]/Frequency"")")

Similar things can be done for the Wavenumber.

Greetings

Walter