.FCSys.Quantities

Types to represent physical values

Information

In FCSys, the unit attribute of each Real variable actually denotes the dimension.1 The fundamental dimensions are angle (A), length (L), mass (M), particle number (N), and time (T). These are combined according to the rules established for unit strings [Modelica2010, p. 210]. Temperature and charge are derived dimensions (see the Units package).

The quantity attribute is not used since the type is the quantity. The displayUnit attribute is only used for quantities that imply a certain display unit.

Methods for unit checking have been established [Mattsson2008, Broman2008, Aronsson2009] and can, in theory, be applied to dimension checking instead.

The Quantities package is abbreviated as Q throughout the rest of FCSys.

The quantities are generally named with adjectives following the noun so that the quantities are grouped when alphabetized. Some quantities are aliases to other quantities but with special implied display units. For example, Temperature is an alias for Potential with a default display unit of K.ootnote{Temperature is a potential in the chosen system of units; see the next section ( ef{sec:Units}).} Also, some quantities have minimum values (e.g., zero for PressureAbsolute). For more information, please see the documentation of the Units package.

1. This misnomer is necessary because Real variables do not have a dimension attribute.↵

Licensed by the Hawaii Natural Energy Institute under the Modelica License 2
Copyright © 2007–2014, Hawaii Natural Energy Institute and Georgia Tech Research Corporation.

This Modelica package is free software and the use is completely at your own risk; it can be redistributed and/or modified under the terms of the Modelica License 2. For license conditions (including the disclaimer of warranty) see FCSys.UsersGuide.License or visit http://www.modelica.org/licenses/ModelicaLicense2.

Contents

Name Description
 Examples Examples
 Acceleration
 Amount
 AmountReciprocal Reciprocal of amount
 Angle
 Angle2 Solid angle
 Area
 AreaSpecific Specific area
 Capacitance
 Density
 DensityRate Rate of density
 ConductanceElectrical Electrical conductance
 ConductivityElectrical Electrical conductivity
 Continuity
 Current
 CurrentAreic Areic current
 CurrentAreicAbsolute Absolute areic current
 CurrentRate Rate of current
 Diffusivity
 Energy
 Fluidity
 Force
 ForceSpecific Specific force
 Frequency
 Inductance
 Length
 LengthReciprocal Reciprocal of length
 LengthSpecific Specific length
 MagneticFlux Magnetic flux
 MagneticFluxAreic Areic magnetic flux
 MagneticFluxReciprocal Reciprocal of magnetic flux
 Mass
 MassSpecific Specific mass
 MassVolumic Volumic mass
 Mobility
 MomentumRotational Rotational momentum
 Number
 NumberAbsolute Absolute number
 Permeability
 Permittivity
 PermittivityReciprocal Reciprocal of permittivity
 Potential
 PotentialAbsolute Absolute potential
 PotentialPerWavenumber Potential per wavenumber
 PotentialRate Rate of potential
 Power
 PowerArea Power times area
 PowerAreic Areic power
 PowerAreicPerPotential4 Areic power per 4th power of potential
 PowerRadiant Radiant power
 Pressure
 PressureAbsolute Absolute pressure
 PressureRate Rate of pressure
 PressureReciprocal Reciprocal of pressure
 ResistanceElectrical Electrical resistance
 ResistanceThermal Thermal resistance
 SurfaceTension Surface tension
 Resistivity
 Time
 TimeAbsolute Absolute time
 TimeLineic Lineic time
 Velocity
 Velocity2 Squared velocity
 VelocityAmount
 Volume
 VolumeRate Rate of volume
 VolumeSpecific Specific volume
 VolumeSpecificAbsolute Absolute specific volume
 VolumeSpecificRate Rate of specific volume
 Wavenumber
 CapacityThermal Thermal capacity
 CapacityThermalSpecific Specific thermal capacity
 CapacityThermalVolumic Volumic thermal capacity
 PotentialChemical Chemical potential
 Temperature
 TemperatureAbsolute Absolute temperature
 TemperatureRate Rate of temperature
 ResistivityThermal Thermal resistivity
 Conductance Conductance
Generated at 2026-04-06T18:18:36Z by OpenModelicaOpenModelica 1.26.3 using GenerateDoc.mos