Saturday, 20 December 2014

fluid dynamics - Power in hydraulic analogy


In hydraulic analogy one compares electrical circuits with water circuits. For the electric case the formula $P = U \cdot I$ for the electric power holds. The analogous formula for water flow would be $P = \Delta p \cdot I_W$ where $\Delta p$ ist the pressure difference and $I_W$ the flow rate of the water through the pipe. I have some questions about this:



  • under what circumstances/assumptions does this analogous formula hold

  • $P$ in the electric case can be interpreted as the energy per second which is dissipated for example in a resistor. Is there a similar interpretation in the water case and why does it hold?

  • with the assumptions from above, how can one derive the formula from first principles (e.g. from Bernoulli-equation or even from Navier-Stokes)?

  • with the assumptions from above, is there a nice conceptual argument, why the formula holds in the water case?




No comments:

Post a Comment

Understanding Stagnation point in pitot fluid

What is stagnation point in fluid mechanics. At the open end of the pitot tube the velocity of the fluid becomes zero.But that should result...