$Ma$  Mach number 
${R}_{E}$  Eulerian correlation coefficient 
${R}_{L}$  Lagrangian correlation coefficient 
${R}_{ij}$  twopoint correlation coefficient of ${u}_{i}$ and ${\omega}_{j}$ ( $i,j=1,2,3$ ) 
$Re$  Reynolds number 
$R{e}_{\tau}$  Reynolds number defined with the friction velocity 
$R{e}_{\theta}$  Reynolds number defined with the momentum loss thickness of turbulent boundary layer 
t  time (s) 
U  mean velocity (m∙s^{−1}) 
${U}_{C}$  propagation speed (m∙s^{−1}) 
$\left({u}_{1},{u}_{2},{u}_{3}\right)$ or $\left(u,v,w\right)$  velocity components in the streamwise, wall normal and spanwise directions, respectively (m∙s^{−1}) 
$\left({x}_{1},{x}_{2},{x}_{3}\right)$ or $\left(x,y,z\right)$  coordinates in the streamwise, wall normal and spanwise directions, respectively (m) 
$\delta $  thickness of turbulent boundary layer (m) 
$\nu $  kinematic viscosity (m^{2}∙s^{−1}) 
$\varphi $ or $\psi $  fluctuations of a variable or component 
$\left({\omega}_{1},{\omega}_{2},{\omega}_{3}\right)$ or $\left({\omega}_{x},{\omega}_{y},{\omega}_{z}\right)$  vorticity components in the streamwise, wall normal and spanwise directions, respectively (s^{−1}) 
Subscripts 

i or j  coordinate indices, ( $i,j=1,2,3$ ) 
r  reference point 
x, y, z  coordinate indices for the streamwise, wall normal and spanwise directions, also represented by 1, 2 and 3, respectively 
Superscripts 

+  normalized with wall units 