  We study the effect of thermal noise on the propagation speed of a planar
flame. We show that this out of equilibrium greatly amplifies the effect of
thermal noise to yield macroscopic reductions in the flame speed over what is
predicted by the noise-free model. Computations show that noise slows the flame
significantly. The flame is modeled using Navier Stokes equations with
appropriate diffusive transport terms and chemical kinetic mechanism of
hydrogen/oxygen. Thermal noise is modeled within the continuum framework using
a system of stochastic partial differential equations, with transport noise
from fluctuating hydrodynamics and reaction noise from a poisson model. We use
a full chemical kinetics model in order to get quantitatively meaningful
results. We compute steady and dynamic flames using an operator split finite
volume scheme. New characteristic boundary conditions avoid non-physical
boundary layers at computational boundaries. New limiters prevent stochastic
terms from introducing non-physical negative concentrations. This represents
the first computation of a model with thermal noise is a system with this
degree of physical detail.
