In the transport panel, "Centered" differencing in space and time are selected. The centered schemes are more accurate than the backward schemes and should be used whenever possible. However, if the spatial grid is too coarse, centered differencing may produce oscillations in results (overshoot and undershoot of true solution). This occurs when the cell Peclet number exceeds 2. Oscillations may be avoided by the use of backward differencing. However this option will introduce numerical dispersion, or artificial smearing of sharp temperature fronts.
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