scholarly journals Mathematical Methodology and Metallurgical Application of Turbulence Modelling: A Review

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1297
Author(s):  
Yannan Wang ◽  
Lingling Cao ◽  
Zhongfu Cheng ◽  
Bart Blanpain ◽  
Muxing Guo
Keyword(s):  
Model Validation ◽  
Turbulent Flows ◽  
Supersonic Jet ◽  
Navier Stokes ◽  
Specific Flow ◽  
Flow Problems ◽  
Eddy Simulation ◽  
Inflow Boundary Condition ◽  
Scale Models ◽  
Rans Models

This paper focusses on three main numerical methods, i.e., the Reynolds-Averaged Navier-Stokes (RANS), Large Eddy Simulation (LES), and Direct Numerical Simulation (DNS) methods. The formulation and variation of different RANS methods are evaluated. The advantage and disadvantage of RANS models to characterize turbulent flows are discussed. The progress of LES with different subgrid scale models is presented. Special attention is paid to the inflow boundary condition for LES modelling. Application and limitation of the DNS model are described. Different experimental techniques for model validation are given. The consistency between physical experimentation/modelling and industrial cases is discussed. An emphasis is placed on the model validation through physical experimentation. Subsequently, the application of a turbulence model for three specific flow problems commonly encountered in metallurgical process, i.e., bubble-induced turbulence, supersonic jet transport, and electromagnetic suppression of turbulence, is discussed. Some future perspectives for the simulation of turbulent flow are formulated.

Simulating flow separation from continuous surfaces: routes to overcoming the Reynolds number barrier

2009 ◽  
Vol 367 (1899) ◽  
pp. 2885-2903 ◽  
Author(s):  
Michael Leschziner ◽  
Ning Li ◽  
Fabrizio Tessicini
Keyword(s):  
Reynolds Number ◽  
Turbulent Flows ◽  
Major Elements ◽  
Wall Layer ◽  
Navier Stokes ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Rans Models ◽  
High Reynolds ◽  
Near Wall

This paper provides a discussion of several aspects of the construction of approaches that combine statistical (Reynolds-averaged Navier–Stokes, RANS) models with large eddy simulation (LES), with the objective of making LES an economically viable method for predicting complex, high Reynolds number turbulent flows. The first part provides a review of alternative approaches, highlighting their rationale and major elements. Next, two particular methods are introduced in greater detail: one based on coupling near-wall RANS models to the outer LES domain on a single contiguous mesh, and the other involving the application of the RANS and LES procedures on separate zones, the former confined to a thin near-wall layer. Examples for their performance are included for channel flow and, in the case of the zonal strategy, for three separated flows. Finally, a discussion of prospects is given, as viewed from the writer's perspective.

Modeling Turbulent Flows in Porous Media

2020 ◽  
Vol 52 (1) ◽  
pp. 171-203 ◽  
Author(s):  
Brian D. Wood ◽  
Xiaoliang He ◽  
Sourabh V. Apte
Keyword(s):  
Porous Media ◽  
Turbulent Flows ◽  
Nuclear Reactor ◽  
Navier Stokes ◽  
Turbulent Regime ◽  
Flows In Porous Media ◽  
Eddy Simulation ◽  
Rans Models ◽  
Using Data ◽  
Averaged Models

Turbulent flows in porous media occur in a wide variety of applications, from catalysis in packed beds to heat exchange in nuclear reactor vessels. In this review, we summarize the current state of the literature on methods to model such flows. We focus on a range of Reynolds numbers, covering the inertial regime through the asymptotic turbulent regime. The review emphasizes both numerical modeling and the development of averaged (spatially filtered) balances over representative volumes of media. For modeling the pore scale, we examine the recent literature on Reynolds-averaged Navier–Stokes (RANS) models, large-eddy simulation (LES) models, and direct numerical simulations (DNS). We focus on the role of DNS and discuss how spatially averaged models might be closed using data computed from DNS simulations. A Darcy–Forchheimer-type law is derived, and a prior computation of the permeability and Forchheimer coefficient is presented and compared with existing data.

On LES Methods Applied to Seal Geometries

2012 ◽  
Author(s):  
James Tyacke ◽  
Richard Jefferson-Loveday ◽  
Paul Tucker
Keyword(s):  
Maximum Error ◽  
Labyrinth Seal ◽  
Navier Stokes ◽  
Final Solution ◽  
Complex Flow ◽  
Eddy Simulation ◽  
Wide Range ◽  
Large Eddy ◽  
Rans Models ◽  
Flow Through

Nine Large Eddy Simulation (LES) methods are used to simulate flow through two labyrinth seal geometries and are compared with a wide range of Reynolds-Averaged Navier-Stokes (RANS) solutions. These involve one-equation, two-equation and Reynolds Stress RANS models. Also applied are linear and nonlinear pure LES models, hybrid RANS-Numerical-LES (RANS-NLES) and Numerical-LES (NLES). RANS is found to have a maximum error and a scatter of 20%. A similar level of scatter is also found among the same turbulence model implemented in different codes. In a design context, this makes RANS unusable as a final solution. Results show that LES and RANS-NLES is capable of accurately predicting flow behaviour of two seals with a scatter of less than 5%. The complex flow physics gives rise to both laminar and turbulent zones making most LES models inappropriate. Nonetheless, this is found to have minimal tangible results impact. In accord with experimental observations, the ability of LES to find multiple solutions due to solution non-uniqueness is also observed.

Current Capabilities of DES and LES for Submarines at Straight Course

2010 ◽  
Vol 54 (03) ◽  
pp. 184-196 ◽  
Author(s):  
N. Alin ◽  
R.E. Bensow ◽  
C. Fureby ◽  
T. Huuva ◽  
U. Svennberg
Keyword(s):  
Statistical Moments ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
Complex Flow ◽  
First Order ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Actuator Disc ◽  
Rans Models ◽  
Coarse Grids

The flow around an axisymmetric hull, with and without appendages, is investigated using large eddy simulation (LES), detached eddy simulation (DES), and Reynolds averaged Navier Stokes (RANS) models. The main objectives of the study is to investigate the effect of the different simulation methods and to demonstrate the feasibility of using DES and LES on relatively coarse grids for submarine flows, but also to discuss some generic features of submarine hydrodynamics. For this purpose the DARPA Suboff configurations AFF1 (bare hull) and AFF8 (fully appended model) are used. The AFF1 case is interesting because it is highly demanding, in particular for LES and DES, due to the long midship section on which the boundary layer is developed. The AFF8 case represents the complex flow around a fully appended submarine with sail and aft rudders. An actuator disc model is used to emulate some of the effects of the propulsor for one of the AFF8 cases studied. Results for the AFF8 model are thus presented for both "towed" and "self-propelled" conditions, where as for the bare hull, only a "towed" condition is considered. For the AFF1 and the "towed" AFF8 cases experimental data are available for comparison, and the results from both configurations show that all methods give good results for first-order statistical moments although LES gives a better representation of structures and second-order statistical moments in the complex flow in the AFF8 case.

scholarly journals Physical consistency of subgrid-scale models for large-eddy simulation of incompressible turbulent flows

2017 ◽  
Vol 29 (1) ◽  
pp. 015105 ◽  
Author(s):  
Maurits H. Silvis ◽  
Ronald A. Remmerswaal ◽  
Roel Verstappen
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flows ◽  
Subgrid Scale ◽  
Eddy Simulation ◽  
Scale Models ◽  
Large Eddy

LES Predictions of Noise Emissions From a Low-Bypass Ratio Military Gas Turbine Engine

2010 ◽  
Vol 133 (4) ◽  
Author(s):  
N. Sinha ◽  
J. Erwin ◽  
C. Kannepalli
Keyword(s):  
Nozzle Exit ◽  
Jet Noise ◽  
Navier Stokes ◽  
Complex Flows ◽  
Turbine Engine ◽  
Flow Problems ◽  
Eddy Simulation ◽  
Standard Procedures ◽  
3D Flows ◽  
Jet Structure

A practical framework for predicting jet structure and noise from military aircraft is described, which is developmental and has been examined for some fundamental jet flow problems. The framework currently utilizes Reynolds-averaged Navier Stokes (RANS) methodology for geometrically complex internal propulsive flowpaths and large eddy simulation (LES) methodology for the jet structure downstream of the nozzle exit. Temporal data from the LES solution is stored on a flared-cylindrical surface surrounding the jet, to be used for noise propagation to the farfield. Earlier applications of RANS methodology combined with the use of analogy-based jet noise codes proved inadequate due to the inability of the noise codes to treat complex 3D flows, such as those associated with multiple nozzles and/or with varied jet noise reduction concepts. Restricting the use of LES (or RANS/LES), methodology to free shear flows remedies the severe grid resolution issues that would be encountered with utilization of LES for modeling internal propulsive flows. The issue of “adequately” initiating the LES solution from a RANS solution profile just downstream of the nozzle exit has been the focus of our exploratory studies and is clearly more complex than standard procedures, such as recycling and rescaling techniques used for simple wall bounded flows. Approaches examined are discussed and unified RANS/LES solutions for several flows are described. The application of this framework to more complex flows requires no fundamental modifications as will also be discussed.

Development of a Continuous Model for Simulation of Turbulent Flows

2005 ◽  
Vol 73 (3) ◽  
pp. 441-448 ◽  
Author(s):  
M. Yousuff Hussaini ◽  
Siva Thangam ◽  
Stephen L. Woodruff ◽  
Ye Zhou
Keyword(s):  
Turbulent Flows ◽  
Continuous Model ◽  
Wave Number ◽  
Navier Stokes ◽  
Subgrid Scale ◽  
Reynolds Stresses ◽  
Eddy Simulation ◽  
Proposed Model ◽  
Large Eddy ◽  
Kolmogorov Flows

The development of a continuous turbulence model that is suitable for representing both the subgrid scale stresses in large eddy simulation and the Reynolds stresses in the Reynolds averaged Navier-Stokes formulation is described. A recursion approach is used to bridge the length scale disparity from the cutoff wave number to those in the energy-containing range. The proposed model is analyzed in conjunction with direct numerical simulations of Kolmogorov flows.

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