# What does 'energy dissipation' in the description of the Kolmogorov Microscales in fluid dynamics mean?

I've asked about microscales before, and thinking more about the problem turned up more basic questions. Consider the length scale of a microscale: $$\eta = \left(\frac{\nu^3}{\epsilon}\right)^\frac{1}{4}$$ With $\nu$ being the viscosity, and $\epsilon$ the energy dissipation. I understand this to mean the energy transfer from turbulent kinetic flow to thermal energy (at this scale). The unit of $\epsilon$ is Watts. What's the reference volume?

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The unit of $\epsilon$ is not Watts, it's Watts per kilogram. That is it is a dissipation in the unit of mass, to get dissipation density (per volume), do $\rho \epsilon$.
For who might be interested [W / kg] is actually [m^2 / s^3], and the units of the dynamic viscosity $\nu$ are squared meters per second [m^2 / s]