High level FDTD question

How to use openEMS. Discussion on examples, tutorials etc

Moderator: thorsten

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dom11990
Posts: 13
Joined: Mon 10 Jun 2019, 10:16

High level FDTD question

Post by dom11990 » Sun 13 Sep 2020, 18:29

I noticed that the energy during a simulation seems to fluctuate up and down. Could you explain what this value represents? If it is the remaining energy in the simulation box, shouldn't it be monotonically decreasing once the excitation signal is done?

thanks!
dom

thorsten
Posts: 1425
Joined: Mon 27 Jun 2011, 12:26

Re: High level FDTD question

Post by thorsten » Sun 13 Sep 2020, 19:54

Hi Dom,

I'm sure I have answered this before but I cannot find it ;)

The displayed energy is only a rough/fast estimate. It for example completely neglects the material distribution (aka assumes everything to be vacuum or metal).

During the excitation the energy in-flow is not constant and some decay/loss may already occur. Thus and up and down is to be expected and normal.
After the excitation is done, the energy should indeed only go down but if energy leaves or enters dielectrics the energy estimation may over- or underestimate the correct value and thus may increase again. But this effect should only be small.

I hope that answers your question?

regards
Thorsten

dom11990
Posts: 13
Joined: Mon 10 Jun 2019, 10:16

Re: High level FDTD question

Post by dom11990 » Fri 18 Sep 2020, 11:09

Yes it does, thanks :)

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