Surface Time Domain Filter
You can use Surface Time Domain filters to create frequency-band filtered surface time histories, which is similar to carrying out inverse surface FFT. Using filtered surface time histories enables you to visualize flow quantitites in a specified frequency range, which can be useful for identifying and analyzing periodic flow structures or time harmonic phenomena such as acoustic waves. Surface Time Domain filtering can only be carried out on scalar quantities saved in .trn files.

Surface Time Domain Filter Properties
- Start Signal
- The start time for the sampling of this object.
- End Signal
- The end time for the sampling for this object.
- Filter Type
- Specifies the type of filter that is applied.
- None
- Does not use a filter.
- Band Pass Filter
- Keeps frequencies between low and high cut-off levels. Adds a sub-node, FIR Filter, in which you can set these levels.
- Band Stop Filter
- Discards frequencies between low and high cut-off levels. Adds a sub-node, FIR Filter, in which you can set these levels.