In fluid mechanics, the Taylor–Proudman theorem (after Geoffrey Ingram Taylor and Joseph Proudman) states that when a solid body is moved slowly within a fluid that is steadily rotated with a high angular velocity Ω Ω , the fluid velocity will be uniform along any line parallel to the axis of rotation. Ω Ω must be large compared to the movement of the solid body in order to make the Coriolis force large compared to the acceleration terms.