Advances in numerical methods for simulating turbulent flows

2004 ◽  
Vol 4 (3/4/5) ◽  
pp. 208 ◽  
Author(s):  
T. Lehnhauser ◽  
S. Ertem-Muller ◽  
M. Schafer ◽  
J. Janicka
Keyword(s):  
Numerical Methods ◽  
Turbulent Flows

Turbulent Flows with Drops and Bubbles: What Numerical Simulations Can Tell Us – Freeman Scholar Lecture

2021 ◽  
Author(s):  
Giovanni Soligo ◽  
Alessio Roccon ◽  
Alfredo Soldati
Keyword(s):  
Numerical Methods ◽  
Best Practices ◽  
Numerical Simulations ◽  
Turbulent Flows ◽  
Multiphase Flows ◽  
Simulation Analysis ◽  
Droplet Size Distribution ◽  
Limited Range ◽  
Numerical Resolution ◽  
Multi Scale

Abstract Turbulent flows laden with large, deformable drops or bubbles are ubiquitous in nature and in a number of industrial processes. These flows are characterized by a physics acting at many different scales: from the macroscopic length scale of the problem down to the microscopic molecular scale of the interface. Naturally, the numerical resolution of all the scales of the problem, which span about eight to nine orders of magnitude, is not possible, with the consequence that numerical simulations of turbulent multiphase flows impose challenges and require methods able to capture the multi-scale nature of the flow. In this review, we start by describing the numerical methods commonly employed and discussing their advantages and limitations, and then we focus on the issues arising from the limited range of scales that can be possibly solved. Ultimately, the droplet size distribution, a key result of interest for turbulent multiphase flows, is used as a benchmark to compare the capabilities of the different methods and to discuss the main insights that can be drawn from these simulations. Based on this, we define a series of guidelines and best practices that we believe important in the simulation analysis and in the development of new numerical methods.

scholarly journals Assessment of numerical methods for fully resolved simulations of particle-laden turbulent flows

2019 ◽  
Vol 179 ◽  
pp. 1-14 ◽  
Author(s):  
J.C. Brändle de Motta ◽  
P. Costa ◽  
J.J. Derksen ◽  
C. Peng ◽  
L.-P. Wang ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Turbulent Flows

scholarly journals Numerical Simulation of the Process of Combustion of a Stoichiometric Hydrogen-Oxygen Mixture in a Steam Generator

2021 ◽  
Vol 9 (2) ◽  
pp. 34-51
Author(s):  
Andrii Avramenko ◽  
Keyword(s):  
Heat Transfer ◽  
Numerical Methods ◽  
Turbulent Flows ◽  
Steam Generator ◽  
Nuclear Power ◽  
Combustion Process ◽  
Three Dimensional ◽  
Radiant Heat ◽  
Oxygen Mixture ◽  
Radiant Heat Transfer

Numerical methods are used to study the process of combustion of a stoichiometric hydrogen-oxygen mixture. The mathematical models were validated using experimental data. The combustion process is modelled in the three-dimensional unsteady formulation. With account of the recommendations of other authors, the turbulent flows are described in the paper using the standard k-ε turbulence model. The Eddy Dissipation Model (EDM) is used to describe the process of combustion of the hydrogen-oxygen mixture. The description of the complex heat transfer between the gas, flame and walls in the paper accounts for radiant heat transfer by using the P1 model. The paper deals with combustion processes in a burner and a model steam generator. Numerical methods were used to evaluate the effect of inlet flow turbulisation, and the flow rate and the method of feeding extra water to the combustion chamber on the process of combustion of the stoichiometric hydrogen-oxygen mixture. The influence of the design and operating mode factors on the alteration of the flame-steam interface and on the flame extinguishing conditions were studied. The results obtained can be used in future in designing equipment that uses hydrogen as a fuel to increase nuclear power plant (NPP) manoeuvrability.

scholarly journals Direct Numerical Simulation of Turbulent Flows Laden with Droplets or Bubbles

2019 ◽  
Vol 51 (1) ◽  
pp. 217-244 ◽  
Author(s):  
Said Elghobashi
Keyword(s):  
Numerical Simulation ◽  
Numerical Methods ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Surface Deformation ◽  
Direct Numerical Simulations ◽  
Solid Particles ◽  
Length Scale ◽  
Single Droplet ◽  
Kolmogorov Length Scale

This review focuses on direct numerical simulations (DNS) of turbulent flows laden with droplets or bubbles. DNS of these flows are more challenging than those of flows laden with solid particles due to the surface deformation in the former. The numerical methods discussed are classified by whether the initial diameter of the bubble/droplet is smaller or larger than the Kolmogorov length scale and whether the instantaneous surface deformation is fully resolved or obtained via a phenomenological model. Also discussed are numerical methods that account for the breakup of a single droplet or bubble, as well as multiple droplets or bubbles in canonical turbulent flows.

scholarly journals Numerical Methods in Laminar and Turbulent Flows

1979 ◽  
Vol 46 (4) ◽  
pp. 967-967
Author(s):  
C. Taylor ◽  
K. Morgan ◽  
C. A. Brebbia ◽  
T. J. R. Hughes
Keyword(s):  
Numerical Methods ◽  
Turbulent Flows ◽  
Laminar And Turbulent Flows

scholarly journals High Order Numerical Methods for the Dynamic SGS Model of Turbulent Flows with Shocks

2016 ◽  
Vol 19 (2) ◽  
pp. 273-300 ◽  
Author(s):  
D. V. Kotov ◽  
H. C. Yee ◽  
A. A. Wray ◽  
A. Hadjadj ◽  
B. Sjögreen
Keyword(s):  
Numerical Methods ◽  
Turbulent Flows ◽  
High Order ◽  
Numerical Dissipation ◽  
Accuracy Improvement ◽  
Local Flow ◽  
Test Filter ◽  
Shock Location ◽  
Grid Points ◽  
Similar Accuracy

AbstractSimulation of turbulent flows with shocks employing subgrid-scale (SGS) filtering may encounter a loss of accuracy in the vicinity of a shock. This paper addresses the accuracy improvement of LES of turbulent flows in two ways: (a) from the SGS model standpoint and (b) from the numerical method improvement standpoint. In an internal report, Kotov et al. ( “High Order Numerical Methods for large eddy simulation (LES) of Turbulent Flows with Shocks”, CTR Tech Brief, Oct. 2014, Stanford University), we performed a preliminary comparative study of different approaches to reduce the loss of accuracy within the framework of the dynamic Germano SGS model. The high order low dissipative method of Yee & Sjögreen (2009) using local flow sensors to control the amount of numerical dissipation where needed is used for the LES simulation. The considered improved dynamics model approaches include applying the one-sided SGS test filter of Sagaut & Germano (2005) and/or disabling the SGS terms at the shock location. For Mach 1.5 and 3 canonical shock-turbulence interaction problems, both of these approaches show a similar accuracy improvement to that of the full use of the SGS terms. The present study focuses on a five levels of grid refinement study to obtain the reference direct numerical simulation (DNS) solution for additional LES SGS comparison and approaches. One of the numerical accuracy improvements included here applies Harten's subcell resolution procedure to locate and sharpen the shock, and uses a one-sided test filter at the grid points adjacent to the exact shock location.

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