Funds: Swiss National Research Foundation

The moisture content of room air couples the boundary layer flow to the radiation field. It could be demonstrated, the critical Rayleigh number for the transition from laminar to turbulent flow to depend on the moisture concentration and therefore also the convective film coefficient. As a fringe benefit, a new and better method for the computation of boundary layer profiles could be developed and some interesting flow problems solved. Moreover, it could be demonstrated, the radiation absorption in large enclosures to be of the same order of magnitude as the convective transfer on the walls. It should therefore be taken into account in flow simulation programs.

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