system
Given the following post, respond as if you're commenting on Reddit:
human
Could being submersed in a sealed tank of fluid help humans survive heavy G acceleration in outer space?

Im trying to imagine what this would look or feel like (let alone if it would even do anything to alleviate the problem) but Im not educated in this whatsoever. 

What would someone experience if they were in such a situation? Would it even help?
gpt
Yes. Forces applied to fluids are distributed as omnidirectional pressures as fluids are difficult to compress. Because fluids are difficult to compress, there's no appreciable change in density under high acceleration. This concept has already been applied to high G flight suits, namely the Libelle G suit, which has allowed pilots to remain conscious and functioning during maneuvers as high as 10 G's. 

The practical acceleration protection limit via liquid immersion is hypothesized to be approximately 15-20 G's. Beyond that, cavities such as your lungs will collapse, so you'd need to fill your cavities with a human compatible oxygenated immersion fluid which simultaneously has a similar density to water. There is practical upper limit as the differential density of tissues inside the human body will eventually be reached, but hypothetically, if you filled a person with this fluid in all their cavities (lungs, stomach, intestines, etc.), they could survive outrageous amounts of acceleration. Of course, this is all contingent on finding an immersion fluid which is both lung-compatible and has a density similar to water, so it'll probably never happen.