The value of the parameter τLF (the parameter that can be edited in the user interface) controls the numerical flux between the elements (nodal discontinuous Lagrange elements) used with the dG method. The numerical flux defines how adjacent elements are connected and how continuous
p and
u are. Different definitions of the numerical flux lead to different variants of the dG method. The flux implemented here is the so-called global Lax–Friedrichs numerical flux. The value of the parameter
τLF should be between 0 and 0.5. For
τLF = 0 a so-called central flux is obtained. Setting
τLF = 0.5 gives a maximally dissipative global Lax–Friedrichs flux.