OpenFOAM unit

2021-03-13 406 words 2 minutes

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OpenFOAM unit

The international system of units (SI) is as follows.

No.	Property	SI unit	USCS unit
1	Mass	kilogram (kg)	pound-mass (lbm)
2	Length	metre (m)	foot (ft)
3	Time	second (s)	second (s)
4	Temperature	Kelvin (K)	degree Rankine (°R)
5	Quantity	mole (mol)	mole (mol)
6	Current	ampere (A)	ampere (A)
7	Luminous intensity	candela (cd)	candela (cd)

The Dimension [kg, m, s, K, mol, A, cd]

Quantity	Unit	Unit in openfoam	Dimension
pressure $P$	$Pa$	$kg^1 \cdot m^{-1} \cdot s^{-2}$	[1 -1 -2 0 0 0 0]
velocity $V$	$m/s$	$m^1 \cdot s^{-1}$	[0 1 -1 0 0 0 0]
temperature $T$	$K$	$K^1$	[0 0 0 1 0 0 0]
concentration $C_i$	$kg/m^3$	$kg^1 \cdot m^{3}$	[1 3 0 0 0 0 0]
body force $\vec{f}$	$N/m^3$	$kg^1 \cdot m^{-2} \cdot s^{-2}$	[ 1 -2 -2 0 0 0 0]
stress tensor $\tau$	$N/m^2$	$kg^1 \cdot m^{-1} \cdot s^{-2}$	[1 -1 -2 0 0 0 0]
thermal conductivity $\lambda$	$W/(m \cdot K)$	$kg^1 \cdot m^{-1} \cdot s^{-3} \cdot K^{-1}$	[1 -1 -3 -1 0 0 0]
mass diffusivity $D_i$	$m^2/s$	$m^2 \cdot s^{-1}$	[0 2 -1 0 0 0 0]
能量源项 $S_f$	$W/m^3$	$kg^1 \cdot m^{-1} \cdot s^{-3}$	[1 -1 -3 0 0 0 0]
density $\rho$	$kg/m^3$	$kg^1 \cdot m^{3}$	[1 3 0 0 0 0 0]
specific heat capacity $c_p$ 导热系数热导率	$J/(kg \cdot K)$	$m^2 \cdot s^{-2} \cdot K^{-1}$	[0 2 -2 -1 0 0 0]
Coefficient of thermal expansion $\beta$ 热膨胀系数	$1/K$	$K^{-1}$	[0 0 0 -1 0 0 0]
gravitational acceleration $\vec{g}$	$m/s^2$	$m^1 \cdot s^{-2}$	[0 1 -2 0 0 0 0]
gas constant $R$	$J/(mol \cdot K)$	$kg^1 \cdot m^1 \cdot s^{-2} \cdot K^{-1} \cdot mol^{-1}$	[1 1 -2 -1 -1 0 0]
molar mass $M$	$kg/mol$	$kg^{1} \cdot mol^{-1}$	[1 0 0 0 -1 0 0]
Enthalpy of fusion $\Delta h$ (latent) heat of fusion 熔化潜热熔化热活化焓	$J/mol$	$kg^1 \cdot m^1 \cdot s^{-2} \cdot mol^{-1}$	[1 1 -2 0 -1 0 0]
活化能 $E$	$J/mol$	$kg^1 \cdot m^1 \cdot s^{-2} \cdot mol^{-1}$	[1 1 -2 0 -1 0 0]
Entropy of fusion $\Delta S$ 活化熵	$J/(K \cdot mol)$	$kg^1 \cdot m^1 \cdot s^{-2} \cdot K^{-1} \cdot mol^{-1}$	[1 1 -2 -1 -1 0 0]
kinematic viscosity $\nu$	$m^2/s$	$m^2 \cdot s^{-1}$	[0 2 -1 0 0 0 0]

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#压力名称，单位，数值式;dimensionSet中的值为量纲的指数，且按照上表中的顺序取值。
dimensionedScalar("p",dimensionSet(1,-1,-2,0,0 ,0, 0),0.0);

#如果需要去掉某个volScalarFiled变量的量纲（如：压力），可以使用命令：
p.dimensions().reset(dimless)

reference
https://cfd.direct/openfoam/user-guide/v8-basic-file-format/#x17-1290004.2.6

https://blog.csdn.net/hanbingchegu/article/details/112557319