Title: A consistent hybrid PDF method: implementation details and application to the simulation of a bluff-body stabilised flame

Authors: B. Naud, C. Jimenez, D. Roekaerts

Addresses: Group of Numerical Simulation and Modelling of Technological Processes, CIEMAT, Avda. Complutense 22, 28040 Madrid, Spain. ' Group of Numerical Simulation and Modelling of Technological Processes, CIEMAT, Avda. Complutense 22, 28040 Madrid, Spain. ' Department of Multi Scale Physics, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands

Abstract: PDF simulations of a bluff-body stabilised flame studied experimentally by Dally et al. have been performed using a hybrid Finite-Volume /particle method in combination with a local time-stepping algorithm. Using mixture fraction as only independent scalar and a flamelet chemistry model, satisfactory results for flow field and mean temperature are obtained. In the proposed hybrid method, the Finite-Volume submodel plays a leading role since it provides the mean velocity, mean velocity gradients, mean pressure gradient, mean dissipation and the gradients of Reynolds stresses used in the particle submodel, resulting in a low bias error. Details on the implementation are given, correction algorithms are presented and a new iteration averaging method is proposed. Despite an inconsistency in the treatment of triple correlation terms, the difference between the Reynolds stresses resolved in the Finite-Volume submodel and extracted from the ensemble of particles appears to be very small, demonstrating that the correction algorithms ensure consistency.

Keywords: probability density function; PDF methods; joint velocity-composition PDF; stochastic Lagrangian modelling; second moment closure; finite-volume method; particle method; bias error; iteration averaging; bluff-body stabilised flame; CFD; computational fluid dynamics; turbulent flows.

DOI: 10.1504/PCFD.2006.009492

Progress in Computational Fluid Dynamics, An International Journal, 2006 Vol.6 No.1/2/3, pp.146 - 157

Published online: 05 Apr 2006 *

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