
Turbulent mixing is an important aspect of a number of practical problems, often combined with combustion or some other reaction. Due to the importance of this problem, considerable effort has been invested in verification (mathematical correctness of numerical solutions) and validation (correctness and applicability of the equations to be solved). A standard test problem of this class is RayleighTaylor mixing, the problem of a heavy fluid over a light one, mixing under the acceleration force of gravity.

