Two semesters. Official website of the State Education Bureau shows that it takes two semesters for graduate students to study fluid mechanics. Every semester 15- 16 weeks, and the study time is 3-4 hours per week. After class, they need reading, doing homework and doing experiments. Fluid mechanics is a branch of mechanics, which mainly studies the static state and motion state of fluid itself and the interaction and flow law between fluid and solid boundary wall when there is relative motion under the action of various forces.