Efficient methods to account for variable property effects in numerical momentum and heat transfer solutions

Numerical solutions of complex turbulent flows that have been achieved under the assumption of constant properties can be corrected with respect to the influence of variable properties for arbitrary (small) heat transfer rates and arbitrary (Newtonian) fluids with an asymptotic approach. It is based on the Taylor series expansion of all properties with respect to temperature. Two methods, one with a special manipulation to circumvent higher order equations are introduced and discussed in detail. Finally it is shown, how DNS and LES solutions, which need extremely large CPU-times, can be treated with respect to the influence of variable properties, at least approximately.