# Blog

## What is hydrodynamics in physics? ## How do you derive the governing laws of fluid motion?

• The governing laws of fluid motion can be derived using a control volume approach. This is equivalent to a “fluidic black box” where all we know about the flow is what is going in and what is coming out of the control volume: mass, momentum, and energy. The control volume (CV) can be fixed or move with the fluid.

## How can hydrodynamics provide information about water flow through a dam?

• Hydrodynamics can provide information on how water might flow through a dam. Hydrodynamics is the study of liquids in motion. Specifically, it looks at the ways different forces affect the movement of liquids.

## How is mass conserved in fluid mechanics?

• Basic fluid mechanics laws dictate that mass is conserved within a control volume for constant density fluids. Thus the total mass entering the control volume must equal the total mass exiting the control volume plus the mass accumulating within the control volume. mass in – mass out = mass accumulating in − m out = m (3.4)  