Pressure (P) Flow rate (Q) Non-dimensional flow rate ( m ˙ T 01 P 01 {\displaystyle {\frac {{\dot {m}}{\sqrt {T_{01}}}}{P_{01}}}\,} ) Flow coefficient ( ϕ {\displaystyle \phi \,} ) Stage loading coefficient ( ψ = V U 2 {\displaystyle \psi ={\frac {V}{U^{2}}}\,} )