Scaling invariance of fluid energy

I have read that the incompressible Navier Stokes equation is preserved by the scaling

$$x’,y’,z’=lambda x, lambda y, lambda z$$
$$t’=lambda^2 t$$
$$u’=(1/lambda) u$$

As I understand it, fluid energy is given by

$$int u^2 dv$$

I am trying to understand what is meant by the claim that the fluid energy is invariant under the scaling $frac{1}{lambda^{d/2}}u(frac{x}{lambda},frac{t}{lambda^2})$ where $d$ is the dimension of space? Could someone explain/derive this scaling invariance of the energy