Units with rational exponents

[DagBruck]

For Modelica there is a discussion about introducing fractional exponents. See modelica/ModelicaSpecification#3012.

One such case is the valve flow equation:

w = Kv*sqrt(dp/(rho/rho0))

where w is the mass flow rate (kg/s), dp is the pressure drop (Pa = N/m2 = kg.m/(s2.m2) = kg/(m.s2)), rho is the inlet density (kg/m3), and rho0 is the reference density (cold water, also in kg/m3).

The unit of Kv is a bit weird: kg/s / (kg/(m.s2))^(1/2) = (kg.m)^(1/2)

Affects 4.4.2 Units of the specification.