The eddy dissipation turbulence energy cascade model

The turbulence energy cascade model used in the Eddy Dissipation Concept for combusting flow is presented and discussed in relation to existing knowledge of relevant turbulent flows. The cascade consists of a stepwise model for energy transfer from larger to smaller scales and for energy dissipation from each scale level by viscous forces. The cascade model makes a connection between the viscous fine structures, where combustion takes place, and the larger transporting eddies which are simulated by turbulence models. Thus, fine structure quantities are expressed in terms of turbulence energy and dissipation. The model is compared to turbulence-energy-spectrum data for the inertial subrange and the dissipative range for nonreacting and reacting flows. The model is also discussed in relation to isotropic decaying turbulence in the transition from initial to final periods of decay. It is concluded that the energy cascade model captures important features of the turbulence structural interaction and dissipation.