Computational Modelling of Buoyancy-Driven Flows in Highly Inclined Tall Cavities

The paper describes the application of unsteady RANS modelling to two buoyancy-driven flows in tall cavities inclined at 15o to the horizontal. In the first case the lower cavity surface is heated, and the upper cooled, resulting in unstable stratification, and in the second case the heating pattern is reversed. A k-epsilon and a stress transport model are used, together with an advanced wall-function approach, and comparisons are made to both experimental measurements and LES results, in order to assess to what extent the models reproduce the complex unsteady and three-dimensional flow patterns present. In the unstably stratified case both models broadly reproduce the measured unsteady flow behaviour, although the RSM gives the better quantitative results. In the stably stratified case the k-epsilon scheme does not fully capture the relatively weak 3D flow structures present, whilst the RSM does, and consequently gives generally good agreement with the measured data.