JWL++ is a simple Reactive Flow model that includes time-dependent reaction
in prompt detonation. It consists of a Murnahan unreacted equation of stat
e, a JWL reacted EOS, a mixer for the two EOS's and a single-time-constant
exponential rate. The mixing can be done by four ways, using either pressur
e or pressure plus artificial viscosity in the rate, and also using either
an analytic function or a pressure equilibrator. The model reproduces the S
ize Effect and detonation front curvature. Detonation failure can also be i
nduced. JWL++ propagates also through an arbitrary geometry in 3-D without
the need for pre-run program burn calculations. It is slower than a JWL/pro
gram "Burn" but faster than "Ignition & Growth".