C f	inertial factor
c p	specific heat capacity (J/kg K)
d	diameter (m)
d s	strut diameter (m)
f	friction factor
Fj(x)	objective function
G	geometric function (Table 1)
h	heat transfer coefficient (W/m2 K)
h v	volumetric heat transfer coefficient (W/m3 K)
H	foam height (m)
i	index (Equations (3) and (4))
k	thermal conductivity (W/m K)
K	permeability (m2)
L	foam length (m)
n	normal vector
NuH	Nusselt number
Nuv	volumetric Nusselt number
p	pressure (Pa)
q	heat flux (W/m2)
Rec	cell-size Reynolds number
ReH	Reynolds number
T	temperature (K)
u	velocity vector (m/s)
u, v	velocity components (m/s)
W	foam width (m)
x, y, z	Cartesian coordinates (m)
Greek letters
ε	porosity
ρ	density (kg/m3)
μ	dynamic viscosity (kg/m s)
Subscripts
c	cell
eff	effective
f	fluid
i	inlet
ref	reference
s	solid
unif	uniform
Superscripts
*	dimensionless
f	fluid
s	solid
Other symbols
<>	porous media volume average
___	x and/or y directions average
Acronyms
GA	Genetic Algorithm
PEC	Performance Evaluation Criterion
PPI	Pores Per Inch