Numerical simulation of rayleigh-benard convection over flat and wavy walls with a transient trynolds-averaged model

摘要

The paper reports on recent attempts to use the single-point turbulence closure in transient computatons (TRANS - Transient Reynolds Averaged Navier-Stokes) to capture the large coherent structure and to analyse its role in Rayleigh-Benard convection at high Rayleigh numbers. The motivation of our study is based on the fact that buoyant flows with heating from below are often dominated by conspicuous arge structure like thermals and plumes. An algebraic heat flux closure is used for the unresolved motion, which includes the low-Re and wall proximity effects allowing integration up to the wall. The results are compared with available DNS data as well with two-dimensional steady RANS computations. Different criteria based on the critical point theory are applied in order to identify spatial organisation of the large coherent structures.