The Theory of Supersonic Combustion Turbulence in the Rotating Detonation Engine

The mechanisms by which turbulence is generated in the two-dimensional (2D) unwrapped model of the rotating detonation engine (RDE) are discussed in this paper. Large-eddy simulations of chemically reacting flows in the RDE using a seven-species, eight-step kinetic mechanism show qualitative similarities in the maps of the invariants of the strain rate tensor, baroclinicity, and the turbulence eddy diffusivity. The observation suggests that the mechanisms for turbulence production in the simplified 2D model involve shear and misalignment between the gradients of pressure and density. The vorticity field is considerably different from the distributions of the strain rates and baroclinicity, as the model used is not capable of capturing turbulence production via vortex stretching. While the classical methods of generating turbulence by passing a laminar flow through a net, or by shear production at a wall, may be absent in the RDE problem, there are indeed available surrogate mechanisms to bring about turbulence.