Which of the following is the correct definition of the Reynolds number?
Where $$\rho$$ = fluid density, U = velocity, L = Length and $$\mu$$ = kinematic viscosity

A

$$\frac{\rho UL}{\mu}$$

B

$$\frac{\rho UL}{\mu^2}$$

C

$$\frac{UL}{\mu}$$

D

$$\frac{\rho UL^2}{\mu}$$