Simulation of Turbulent Natural Convection in a Rectangular Enclosure by Use of k-ω-sst Model

  • M. N. Maithima
  • K. O. Awuor
  • J. E. Nafula
Keywords: turbulence, natural convention, rectangular enclosure, k-ω-sst model


Turbulent flow is a type of flow that is highly unsteady, undergoes irregular fluctuations and three dimensional in motion. Naturally, turbulent flow is diffusive and dissipate energy. The aim of this study is to numerically investigate natural turbulent convection in a three dimensional rectangular enclosure using k-ω-sst model. The research is to investigate temperature and velocity distribution in a rectangular enclosure with constant Rayleigh number (Ra = 7.80 x 1011) and varying aspect ratios (1.5 ≥ A.R. ≥ 0.75). The equations governing the flow are Momentum, Continuity and Energy equations. The equations are first time averaged. The averaging process introduced non-linear terms; Reynolds stress and heat flux which are modelled using k-ω-sst model. The emerging equations after modelling are non-dimensionalized and then discretized by finite difference method and the results solved using ANSYS Fluent. The results showed that, increasing the height of the enclosure decreases the aspect ratio, which in turn strengthens the stream function consequently increasing the number of vortices.