Flux limiter

Summary

A flux limiter is a function used in high-resolution schemes for conservation laws to blend a low-order, non-oscillatory numerical flux with a high-order one. It looks at the ratio of neighbouring slopes of the solution. Where the solution is smooth it lets the high-order flux act, and near jumps or extrema it switches back to the low-order flux. In this way the scheme is second-order accurate in smooth regions and still free of spurious oscillations. This gets around the limits that Godunov's theorem sets for linear schemes. Standard examples are the minmod, superbee and van Leer limiters.