r  m  Radial distance to rotation axis in centrifuge 

$\overline{r}$  m  Average radial distance in centrifuge 

r_{0}  m  Radial reference distance in centrifuge at z = 0 (base of sediment or top of cream) 

RGF    Relative Gravity Force = acceleration factor in centrifuge with respect to free fall (RGF = 1 in earth’s gravity)  $\text{RGF}=\leftg/{g}_{grav}\right$ _{ } 
s    Structured fabric phase containing dispersed solids and emulsion droplets 

t  s  Time 

T^{ }    Dimensionless time  $T=t/\tau $ 
v  m/s  Speed 

$U\left(\varphi \right)$    Dimensionless fluid flow speed  $U\left(\varphi \right)=\delta {\varphi}^{2}/\left(1\varphi \right)$ 
V  m^{3}/(m^{2}s)^{ }  The volume per unit time per unit lateral area 

WE    whole egg 

x  m  Spatial coordinate, often horizontal 

z  m  Spatial coordinate, often vertical. Increases with height 

Z  m  Horizontal distance from bottom vessel in centrifuge  $Z={r}_{0}r$ 
δ    Dimensionless number for relative importance of gravity over elasticity in earth’s gravity (RGF = 1) and in centrifuge  $\delta =\text{RGF}\left(\Delta \rho {g}_{grav}H/{\epsilon}_{0}\right){\left(1{\varphi}_{0}\right)}^{3}/{\varphi}_{0}^{4}$ 
ε  N/m^{2}  Elasticity 

$\varphi $    Porosity, here fractional volume available for fluid  $\varphi ={\varphi}_{w}$ _{ } 
${\varphi}_{s}$    Volume fraction dispersed phase (solids, air, oil, and structurant) 

${\varphi}_{w}$    Porosity = local fractional volume available for fluid  ${\varphi}_{w}+{\varphi}_{s}=1$ 
${\varphi}_{0}$    Initial porosity, initial volume fraction available for fluid 

μ  Pas  Viscosity of a fluid, μ_{w} for aqueous phase 

p    pi  p = 3.141592654 
P    Dimensionless Pi number 

ρ  kg/m^{3}  Density, mass per unit volume; ρ_{s} for dispersed, ρ_{w} for fluid 

τ^{ }  s  Relaxation time  $\tau =\left(\left(1{\varphi}_{0}\right)/{\varphi}_{0}\right)2\mu {H}^{2}/\left({k}_{0}{\epsilon}_{0}\right)$ 
ω  rad/s  Cyclic frequency  $\omega =2\text{\pi}f$ 
ξ    Dimensionless vertical distance from bottom of vessel  $\xi =z/H$ 
Θ    Dimensionless height of depleted zone  $\Theta =\Omega /H$ 
Ω  m  Height of depleted zone 

Δρ  kg/m^{3}  Average density difference between dispersed and fluid phase, positive in sedimentation  $\Delta \rho ={\rho}_{s}{\rho}_{w}$ 