Large eddy simulation of turbulent crossflow in tube bundles

Abstract

Flow characteristics have been examined in non-staggered and staggered tube bundles using the large eddy simulation method. The simulations use two subgrid scale closure models that are compared to available experimental data in the form of power spectral densities and bound spectra of lift and drag forces. In large eddy simulation, the large scale motions are explicitly resolved while the small scale motions are modeled. The simulations have been performed adopting the large eddy simulation computer code GUST. Rigid two-dimensional tube bundle arrays are considered with staggered and non-staggered geometries. Non-staggered array simulations are carried out for a deep bundle case (100 × 100 grid) and an inflow/outflow case (400 × 160 grid). A deep bundle staggered array simulation (154 × 178 grid) is also performed. Power spectral densities of lift and drag forces correlate well with the experimental data. Correlation functions are used to describe turbulence characteristics. Flow visualization has enabled the distinction of different characteristics within the flow, such as switching effects within a tube bank and in the wake of the bundle flow. These are similar observations as in experimental findings. Comparison of the power spectral densities to bound spectra shows good agreement. The results indicate that the large eddy simulation technique is capable of turbulence prediction in complex geometries and may be used as a viable engineering tool with the careful consideration of the subgrid scale closure model.