Nu is a dimensionless quantity that is used to describe the motion of fluids. It is a measure of the ratio of the viscous forces to the inertial forces and is a function of the fluid’s viscosity, density, and velocity.

## Other related questions:

### Q: What is N in fluid dynamics?

A: N is a dimensionless parameter used in fluid dynamics to describe the relative importance of viscous and inertial forces.

### Q: What does the Nusselt number tell you?

A: The Nusselt number is a dimensionless number that is used to describe heat transfer in fluid systems. It is named after Wilhelm Nusselt, who first proposed it in his 1918 paper “On the convective heat transfer in turbulent flow.” The Nusselt number is defined as the ratio of convective heat transfer to conductive heat transfer.

### Q: What is fluid inertia?

A: In fluid mechanics, fluid inertia is the resistance of a fluid to changes in its velocity. It is caused by the fluid’s resistance to changes in its momentum and is a function of the fluid’s mass and velocity.