Mesoscopic Modelling and Stochastic Simulations of Turbulent Flows
نویسنده
چکیده
A stochastic representation of the dynamics of the Burger's turbulence model and of the two{dimensional turbulence is developed. The random velocity eld is regarded as a multivariate stochastic Markov process deened by a master equation. It is shown that Burgers' equation and the two{dimensional Navier{Stokes equation are obtained as the macroscopic equations for the averages of the underlying stochas-tic process. Furthermore, by means of the {expansion the equations governing the hydrodynamic uctuations are derived from the master equation. In addition, the hierarchy of equations of motion for the turbulent correlation functions is obtained from the time{evolution equation for the characteristic function corresponding to the master equation. The Burgers' turbulence model and the two{dimensional turbulence for very high Reynolds numbers are investigated numerically by means of stochastic simulations of the master equations.
منابع مشابه
Three-dimensional PDF simulation of a piloted turbulent non-premixed jet flame
Turbulent combustion is an important process in many technical applications, e.g. industrial gas furnaces used for heating water, production of steam and combustion in jet and diesel engines. To control the turbulent combustion, simulation tools with predictive power are required. The basic equations for turbulent combustion are well known, but their application to the complex flows appearing i...
متن کاملStochastic Modelling for Two-phase Flow Simulations: Interests and Examples
This paper discusses stochastic models applied to modelling and simulation of turbulent dispersed two-phase flows. The stochastic approach presents strong advantages compared to classical approaches which attempt to solve field equations for some statistical averages: polydispersed flows are treated naturally without specific assumptions and detailed information is provided on various particle ...
متن کاملConvergence to a model in sparse-Lagrangian FDF simulations
This work investigates the problem of distinguishing modelling assumptions and numerical errors in sparseLagrangian FDF (Filtered Density Function) methods. A new interpretation of sparse modelling with Curl’s mixing, which does not require an additional observation scale nor filtering, is given. The diffusion effects induced by mixing, which were previously interpreted as numerical errors, are...
متن کاملAssessment of Turbulent Models in Computation of Strongly Curved Open Channel Flows
Several rigorous turbulent models have been developed in the past years and it can be seen that more research is needed to reach a better understanding of their generality and precision by verifying their applications for distinct hydraulic phenomena; under certain assumptions. This survey evaluates the performance of Standard k-ε, Realizable k-ε, RNG k-ε, k-ω and RSM models in predicting flow ...
متن کاملUse of Stochastic Turbulence Models in Jet Acoustics
There are many approaches to determine the sound propagated from turbulent flows. In hybrid methods, the turbulent noise source field is computed or modeled separately from the far-field calculations. To have an initial and quick estimation of the sound propagation, less computationally intensive methods can be developed using stochastic models of the turbulent fluctuations. In this paper, ...
متن کامل