Symbol	Unit	Physical Meaning
μ	Pa·s	Dynamic viscosity of air
Ls	nm	Slip length
σv	—	Momentum accommodation coefficient
Kn	—	Knudsen number
λ	nm	Gas mean free path
df	nm	fiber diameter
Δp	Pa	Pressure drop across the sample
u	m/s	periodic velocity
h	m	Sample thickness
σ	Ns/m4	Flow resistivity; resistance to airflow through porous media
α∞	—	Tortuosity; ratio of effective to straight acoustic path length
ϕ	—	Porosity; fraction of void volume in the total volume
Λ	μm	Viscous characteristic length; controls viscous dissipation scale
Λ′	μm	Thermal characteristic length; controls heat exchange scale
Vp	M3	Pore volume
Sp	M2	Effective surface area of pores
ρf	kg/m3	Air density
c0	m/s	Speed of sound in air
Zc	Pa·s/m	Characteristic acoustic impedance
k	m−1	Complex wave number
ρ(ω)	kg/m3	Effective density
K(ω)	Pa	Effective bulk modulus
γ	—	Ratio of specific heats of air
pA	Pa	Standard atmospheric pressure
ω	rad/s	Angular frequency
f	Hz	Acoustic frequency
Pr	—	Prandtl number
ρ	kg/m3	Bulk density of the material
Pin	Pa	Inlet pressures of the nanofiber
Pout	Pa	Outlet pressures of the nanofiber
c	Pa	Constant pressure drop
ϕm	—	Measured porosity
ρfiber	kg/m3	Intrinsic density of the nanofiber
Vt	m3	Total volume of the domain