[jealor]

Originally Posted by LuckyTran

That is only the turbulent dissipation, there is also a laminar/molecular dissipation (which is related to the laplacian term in the navier-stokes).


There's also just dissipation coming from numerics.

Thanks for your reply!

I find that there is dissipation loss for laminar flow and calculated it as the equation implies. However the laminar loss is much smaller than the turbulent loss. And the sum of the two loss is also smaller than the power loss calculated by the torque and power calculated on the shaft. So I was thinking there might be some power that can not be transferred to the flow field so it can not be calculated……