Gundalf evolved as an airgun modelling package in its first 15 years to meet the needs of source array modelling with the almost universally popular, flexible and extraordinarily reliable airgun. This has been supported by the wide availability of high quality calibration data for this most enduring of marine sources.
It retains its dominance but there are other sources available for more specialised use and in attempts to mitigate further the effects of high intensity acoustic waves on marine life.
Multi-element sources of any kind all fall into the concept of "notional sources", so in 2021-22, Gundalf was enhanced to model some other marine source types, taking advantage of its built handling of pressure-field interaction. Such modelling is inherently more experimental than the mature state of airgun modelling but where there is any kind of calibration data available, it can be done. So with the caveat that we still consider the modelling of these alternative (i.e. anything not an airgun) sources as experimental, the sources included in March 2022 onwards are a small number of Sparker and Boomer sources as used in site surveying and shallow-water seismic data acquisition, and a generic marine vibrator, which may prove to be very flexible in its multi-element forms.
We look forward to any feedback on these as we go forward but they are specified in exactly the same way as airgun sources. When you start Gundalf, it gives you the choice of the type of source for this array (they cannot be mixed). After a session with a particular kind of source, it can be reset using the "Switch source type" menu option in the user menu (the one headed by your email address).
The sources are:-
For any of these sources, we have currently restricted the options available to a normal model or a full model with directivity. At some stage when we have more experience and more data, we will extend this to environmental modelling.