When you are searching for filename and are unsure of the full filename, you can search for part of the filename with a leading truncation or a following truncation!
For example, if the document you are searching for has the filename, "BRLH Storage.xls" you could run a search either like this, filename("BRLH!")
or like this, filename("!Storage.xls").
As you can see from the two examples provided, the same document resulted in both searches.
Please feel free to contact DISCO support with any questions you may have!