The volume flow changes proportionally to the speed (cf. Figure 3.3.1.a and 3.3.1.b):
\frac{q_{V,I}}{q_{V,II}}=\frac{n_I}{n_{II}}
All pressures (static, dynamic, total) change proportionally to the square of the speed (cf. Fig. 3.3.1.a):
\frac{p_I}{p_{II}}=\left(\frac{n_I}{n_{II}}\right)^2=\left(\frac{q_{V,I}}{q_{V,II}}\right)^2
The power requirement at the shaft changes proportionally to the third power of the speed (cf. Figure 3.3.1.b):
\frac{P_\mathrm{I}}{P_{\mathrm{II}}}=\left(\frac{n_\mathrm{I}}{n_{\mathrm{II}}}\right)^3=\left(\frac{q_{V,\mathrm{I}}}{q_{V,\mathrm{II}}}\right)^3
Figure 3.3.1.a: Change of pressue
Figure 3.3.1. b: Change of shaft power