symbol 
quantity 

discrete timestep 

grid size 

internal energy density (per mass unit) 

total (internal + kinetic) energy 

total (internal + kinetic + potential) energy 

total (internal + kinetic + magnetic) energy 

frequencydependent intensity 

normal vector of length unity 

frequency 

pressure 

mass density 

internal energy density (per volume) 

unity tensor 

velocity vector
