I solved a fluids problem recently and had a question about the answer. The question was, given a fluid in a rotating cylinder with gravity acting axially, what is the profile of the meniscus. I found the answer, which matched the book's, to be a parabolic meniscus. However, when solving I did not use the Young-Laplace equation. So when should you use Young-Laplace equation when dealing with pressure, and when should you consider surface tension?