Roman Letters
a	load parameter
CDES	constant in the blending function for the DES model, CDES = 0.61
Cu	the tangential component of absolute velocity [m/s]
∆Cu	increment of the tangential component of absolute velocity [m/s]
Cz	the axial component of absolute velocity [m/s]
e	specific internal energy [m2/s2]
h	specific enthalpy [m2/s2]
iopt	optimal incidence angle [degree]
k	turbulence kinetic energy [m2/s2]
ki	volume force vector [N]
lFR	length of the chamber line at the mid-span of the FR [m]
lRR	length of the chamber line at the mid-span of the RR [m]
ni	unit normal vector to a surface
Pji	surface stress tensor without normal stress component [N/m2]
Pt,in	averaged total pressure rise at the inlet [Pa]
Pt,ES	total pressure rise of the entire stage [Pa]
Pt,FR	total pressure rise of the FR [Pa]
Pt,RR	total pressure rise of the RR [Pa]
Pt,out	averaged total pressure rise at the outlet [Pa]
Pr	Prandtl number
Prt	turbulent Prandtl number
P1	passage 1
P2	passage 2
P3	passage 3
p	pressure [Pa]
qi	heat flux [W/m2]
r	radius [m]
$S_{PRO,\overline{C}}$	entropy production rate by heat transfer with mean temperature gradients [W/(K·m3)]
$S_{PRO,C^{\prime }}$	entropy production rate by heat transfer with fluctuating temperature gradients [W/(K·m3)]
$S_{PRO,\overline{D}}$	entropy production rate by direct dissipation [W/(K·m3)]
$S_{PRO,D^{\prime }}$	entropy production rate by turbulent dissipation [W/(K·m3)]
s	entropy [J/K]
T	temperature [K]
t	time [s]
ti	surface force vector [N]
ui	velocity vector [m/s]
${\overline{u}}_i$	steady component of velocity vector [m/s]
$u_i^{\prime }$	fluctuation of velocity vector [m/s]
v	specific volume [m3/kg]
W	relative velocity [m/s]
x	axial spacing parameter
xi	displacement vector [m]
Greek Letters
β*	constant in the k-ω model, β* = 0.09
δij	Kronecker delta
∆	grid spacing [m]
ηt	total pressure efficiency of the CRF [%]
λ	thermal conductivity [W/(m·K)]
μ	dynamic viscosity [Pa·s]
μt	eddy viscosity [Pa·s]
ρ	density [kg/m3]
τji	surface stress tensor [N/m2]
Φ	viscous dissipation of mechanical energy [W/m3]
${\Phi }_{\theta }/T^2$	EPR by heat transfer [W/(K·m3)]
ω	turbulence eddy frequency [1/s]