Discretization effects in TLM diffusion models

The standard methods for bringing a TLM diffusion model to convergence are necessary but tedious. However, much time and effort can be saved if the in itial choices of elemental size and iteration timestep are appropriate. Her e we consider the general form of the solution to the diffusion equation an d sample the component dynamics to determine the impulse invariant response . We then derive a convenient method for charting the discrepancy between t he coefficients of the continuous description and the impulse invariant tra nsformation, as this discrepancy varies with discretization of space and ti me. The use of the curves in estimating appropriate elemental size and iter ation timestep is described. Copyright (C) 2000 John Wiley & Sons, Ltd.