I Unit of Specific Speed

1. Aug 2, 2016

Hi
Specific Speed is defined as:
Ns=N(Q^0.5)/(H^.75)
How Dimensional Analysis of it can be done? Unit of N is 1/sec and Ns is unitless. Then Dimension of Q^0.5 must be equal to dimension of H^0.75. It seems no to be equal.

Last edited: Aug 2, 2016
2. Aug 2, 2016

Nidum

What is your question ?

3. Aug 2, 2016

Please analyse the formula dimensionally.

4. Aug 2, 2016

Nidum

Your formula is only pseudo dimensionless . The calculated Ns number is only valid for a specific system of units .

The proper dimensionless formula has a g in the denominator . Explained reasonably well in Wikipedia .