Large Eddy Simulation of Turbulent Heat Transfer in Pipe Using NEK5000 Based on the Spectral Element Method and Uncertainty Quantification by GCI Estimation

Abstract

Large eddy simulation is performed in heat transfer of turbulent pipe flow with NEK5000 code based on spectral element method to study uncertainty quantification by Grid Convergence Index. The turbulent pipe flow with heat transfer is considered with Reynolds number Re = 19,000 and Prandtl number Pr = 0.71. Three meshes (fine, medium, and coarse) with the fixed interpolation polynomial order, eight and three orders (4th, 6th, and 8th) of interpolation polynomial with the fine mesh are examined. The effects of different grid and interpolation polynomial order are studied to highlight the effectiveness of high-order spectral element. Besides that, to quantify the uncertainty by grid and polynomial order in the numerical results, the Grid Convergence Index using two modified versions from original Roache's GCI method are estimated based on simulation results. Two modified versions include the modification of Roache's GCI method described in the ASME VV 20-2009 guideline and the simplified least square method version GCI.