Paper Conference

Proceedings of BauSim Conference 2006: 1st Conference of IBPSA-Germany and Austria


Experimentelle und numerische Untersuchung von Auftriebsströmungen im Übergangsbereich

W. Haupt, Treeck C. van

Abstract: Numerical calculations of buoyancy induced natural convection in the laminar/turbulent transitional region (108 < Ra < 1010) are of great practical relevance in the scope of ventilation in buildings. Nevertheless there exist only a few validation measurements for this type of flow. The previous work (Haupt, 2001-2005) concerned free convection in a rectangular cavity in a laboratory test environment with heated top and cooled bottom plate, respectively. Both experiment and simulation show transient behaviour with slow fluctuations around the vertical axis. It was concluded that these kinds of flows are to be modeled in a solely transient and three-dimensional manner and without utilizing geometrical symmetries. The conclusion was misunderstood (Zimmermann, 2005) in the sense that CFD tools are generally not applicable for predicting this type of flow. Moreover, (Zimmermann, 2005) doubts the transient character of the flow under consideration by presenting own simulation results. In this contribution, the latter practical example will be compared to the original findings which are presented in a new and concise way.
Pages: 53 - 54