$\rho$	Material density, kg/m3
$V$	Velocity vector, m/s
$P$	Pressure, Pa
$F$	Volume force, N
$\mu$	Viscosity, Pa·s
$C_P$	Specific heat capacity, J/(kg·K)
$\Delta H$	Phase change of latent heat, J
${\rm K}$	Thermal conductivity, W/(m·K)
${\mathsf{\alpha }}_1$	Metal phase coefficient
${\mathsf{\alpha }}_2$	Gas phase coefficient
$\Delta H_V$	Evaporation enthalpy change, J
$R$	Ideal gas constant
$R_g$	General gas constant
u, v, w	Velocity component, m/s
$\mathrm{g}$	Gravity acceleration, m/s2
$m_V$	Evaporation rate per volume
$P_w$	Laser power, W
$\theta$	Porosity ratio
$\eta$	Laser absorption coefficient
$\mathrm{P}$	Laser power, W
$z_i$	Coordinate of lower heat source
$r_i$	Radius of lower heat source, μm
$\mathsf{\chi }$	Heat flow peak proportional coefficient
$v$	Scanning velocity, mm/s
$z_e$	Powder thickness, μm
$r_e$	Beam spot radius, μm
$h_c$	Convective heat transfer coefficient
${\sigma }_s$	Boltzmann constant
$ϵ$	Radiative coefficient
$Q$	Laser heat flux density, J/(m2·s)
$P_0$	Atmospheric pressure, Pa