The discussion centers on calculating water velocity from static pressure in a vertical tube using Bernoulli's equation and Poiseuille's Law. Bernoulli's equation relates pressure, velocity, and elevation, while Poiseuille's Law applies to laminar flow, linking flow rate to pressure difference and viscosity. Understanding these principles is crucial for determining flow rates in fluid dynamics. The conversation highlights the importance of knowing additional parameters beyond static pressure to accurately calculate water velocity.
PREREQUISITESEngineers, fluid dynamics researchers, and students studying hydraulics or fluid mechanics will benefit from this discussion, particularly those interested in calculating flow rates in confined fluid systems.
In the first part, you write "static pressure(water in a tube or column) not moving." Then you ask about determining velocity. This is confusing.Idea04 said:with static pressure(water in a tube or column) not moving. Is there an equation I can use to determine the velocity of the water by the pressure of the water in the tube or column.
In the case of smooth flow (laminar flow), the volume flowrate is given by the pressure difference divided by the viscous resistance. This resistance depends linearly upon the viscosity and the length, but the fourth power dependence upon the radius is dramatically different. Poiseuille's law is found to be in reasonable agreement with experiment for uniform liquids (called Newtonian fluids) in cases where there is no appreciable turbulence.