Lagrangian Fluid Dynamics for Combustion Modelling.
NAVAL RESEARCH LAB WASHINGTON DC
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Recent flow visualization experiments have shown the need to follow the behavior of dynamically interacting coherent structures in both cold flows and flames. Since these structures move the fluid, a Lagrangian approach is especially useful in theoretical calculations because we can observe the interaction of a particular fluid element with its changing environments as the flow evolves. One-dimensional Lagrangian flame models are successful because they also minimize the effects of numerical diffusion which is the bane of laminar flame calculations. However, most two- and three-dimensional flame models are Eulerian because of problems in standard Lagrangian formulations for multi-dimensional models and because phenomenological turbulent diffusion terms are usually added which mask the numerical diffusion. The purpose of this paper is to describe one- and multi-dimensional Lagrangian algorithms which eliminate many of the problems previously associated with this approach. An example of a one-dimensional flame calculation which incorporates the new ideas will be given. Finally, examples will be given of the two-dimensional Lagrangian triangular gridding technique and it will be indicated how this may be applied to multi-phase combustion problem. Author
- Combustion and Ignition