Spezialfragen Bauphysik
Chair of Building Physics

 u p d a t e   Thursday, December 04, 2003


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The influence of infrared absorption by the moisture content of the air on the boundary flow in rooms

Collaborator: Matti Brändli, Dipl.Phys. ETHZ
Start: 01/1995
End: 11/1998

Contacts: B. Keller, E. Magyari


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.


The goal:

Quantitative formulation of the influence of the radiation impact on the stability of the boundary layer.

Index terms:



infrared spectroscopy, boundary layer, air flow, water vapour

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