Dimensional Analysis of Specific Speed: Explained

  • Context: Undergrad 
  • Thread starter Thread starter Mikealvarado100
  • Start date Start date
  • Tags Tags
    Specific Speed Unit
Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
3 replies · 2K views
Mikealvarado100
Messages
52
Reaction score
0
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.
Please explain it.
 
Last edited:
Physics news on Phys.org
Please analyse the formula dimensionally.
 
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 .