The phrase "already well understood" is correct and usable in written English.
It can be used to indicate that something has been comprehended or grasped prior to the current moment or discussion.
Example: "The concept of gravity is already well understood by most students in the class."
Alternatives: "previously comprehended" or "already grasped".
But the essential problem is already well understood.
The problems of distinguishing one John Smith from another are already well understood in the library community.
It is already well understood within the party that there are moves to ditch its policy on scrapping tuition fees.
This bioprocess is already well understood and there exist various MFA models aiming at understanding the fungal metabolism and production pathways.
The response to protons, which was already well understood, was used to verify the mass model, the simulation settings, and the post-processing software.
But generating optical signals would be cheaper and easier if lasers could be made from silicon, whose properties are already well understood by the semiconductor industry.
One bill would authorize the U.S. Government Accountability Office to study the capacity of the U.S. treatment system -- though the system's capacity, or lack thereof, is already well-understood.
The 95% that is right will already be well understood and the rest will still be wrong".
He added: "The source of the flooding is already fairly well understood but this report should also consider where and why any breaches occurred, show where improvements can be made and help us plan ahead to improve our resilience and response to such events in the future".
Some studies resorted to use of structured questionnaires and telephone surveys, not the best means to explore cultural phenomena that are not already fairly well understood.
The surveillance protocols in Taiwan remained essentially the same throughout the data period since, by the time the data were collected, clinical characteristics of the pH1N1 infection had already been well understood from the spring outbreaks around the world.
