.ThermoPower.Choices.Flow1D.FFtypes .ThermoPower.Choices.Flow1D.FFtypesType, constants and menu choices to select the friction factor
type FFtypes = enumeration(Kfnom "Kfnom friction factor", OpPoint "Friction factor defined by operating point", Cfnom "Cfnom friction factor", Colebrook "Colebrook's equation", NoFriction "No friction");