Partially-Averaged Navier-Stokes Model for Turbulence: A Reynolds-Averaged Navier-Stokes to Direct Numerical Simulation Bridging Method

2005 ◽  
Vol 73 (3) ◽  
pp. 413-421 ◽  
Author(s):  
Sharath S. Girimaji
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Navier Stokes ◽  
Control Parameters ◽  
Closure Model ◽  
Filter Width ◽  
Model Filter ◽  
Reynolds Averaged Navier Stokes ◽  
Model Equations ◽  
Two Parameters

A turbulence bridging method purported for any filter-width or scale resolution—fully averaged to completely resolved—is developed. The method is given the name partially averaged Navier-Stokes (PANS) method. In PANS, the model filter width (extent of partial averaging) is controlled through two parameters: the unresolved-to-total ratios of kinetic energy (fk) and dissipation (fε). The PANS closure model is derived formally from the Reynolds-averaged Navier-Stokes (RANS) model equations by addressing the following question: if RANS represents the closure for fully averaged statistics, what is the corresponding closure for partially averaged statistics? The PANS equations vary smoothly from RANS equations to Navier-Stokes (direct numerical simulation) equations, depending on the values of the filter-width control parameters. Preliminary results are very encouraging.

scholarly journals Numerical investigation of particles turbulent dispersion in channel flow

2012 ◽  
Vol 16 (5) ◽  
pp. 1510-1514
Author(s):  
Tian Li ◽  
Li-Hao Zhao ◽  
Xiao-Ke Ku ◽  
Helge Andersson ◽  
Terese Lovas
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Numerical Investigation ◽  
Channel Flow ◽  
Particle Distribution ◽  
Turbulent Dispersion ◽  
Wall Turbulence ◽  
Navier Stokes ◽  
Reynolds Averaged Navier Stokes ◽  
Over Time

This paper investigates the performance of Reynolds-averaged Navier-Stokes model on dispersion of particles in wall turbulence. A direct numerical simulation of wall-bounded channel flow with particles suspensions was set as a benchmark. The standard k-? model coupled with two different eddy interaction models was used in Reynolds-averaged Navier-Stokes model and compared to the direct numerical simulation. Detailed comparisons between direct numerical simulation and Reynolds-averaged Navier-Stokes model on particle distribution evolving over time were carried out.

Direct numerical simulation, large eddy simulation and unsteady Reynolds-averaged Navier—Stokes simulations of periodic unsteady flow in a low-pressure turbine cascade: A comparison

2003 ◽  
Vol 217 (4) ◽  
pp. 403-411 ◽  
Author(s):  
V Michelassi ◽  
J. G. Wissink ◽  
W Rodi
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Large Eddy Simulation ◽  
Direct Numerical Simulation ◽  
Low Pressure ◽  
Navier Stokes ◽  
Stagnation Region ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Reynolds Averaged Navier Stokes

The unsteady periodic flow in a low-pressure (LP) prismatic turbine vane with incoming wakes is computed by direct numerical simulation (DNS), large eddy simulation (LES) and unsteady Reynolds-averaged Navier—Stokes simulations (URANSs). The results are compared with existing measurements at a Reynolds number Re = 5.18 × 104 which reveal the presence of a large unsteady stalled region on the suction side. Both DNS and LES suggest that the boundary layer separates while being still laminar, with subsequent turbulent reattachment. Several URANSs with and without a transition model and a constraint on the turbulence time-scale designed to prevent excessive production in the stagnation region are analysed and compared with the DNS and LES. The useful information provided by DNS and LES has made it possible to improve the results of the URANSs, which ensure a fair reproduction of the flow, especially in terms of blade load and losses, although they partly fail to detail the complex wake—boundary layer interaction in the separated flow region.

Study of turbulent flow past a square cylinder using partially-averaged Navier–Stokes method in OpenFOAM

2020 ◽  
Vol 234 (14) ◽  
pp. 2821-2832 ◽  
Author(s):  
Arnab Chakraborty ◽  
HV Warrior
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flow ◽  
Turbulent Flows ◽  
Normal Direction ◽  
Navier Stokes ◽  
Square Cylinder ◽  
Mean Velocity ◽  
Wide Range ◽  
Reynolds Averaged Navier Stokes

The present paper reports numerical simulation of turbulent flow over a square cylinder using a novel scale resolving computational fluid dynamics technique named Partially-Averaged Navier–Stokes (PANS), which bridges Reynolds-Averaged Navier–Stokes (RANS) with Direct Numerical Simulation (DNS) in a seamless manner. All stream-wise and wall normal mean velocity components, turbulent stresses behavior have been computed along the flow (streamwise) as well as in transverse (wall normal) direction. The measurement locations are chosen based on the previous studies so that results could be compared. However, the Reynolds number ( Re) of the flow is maintained at 21,400 and K– ω turbulence model is considered for the present case. All the computations are performed in OpenFOAM framework using a finite volume solver. Additionally, turbulent kinetic energy variations are presented over a wide range of measurement planes in order to explain the energy transfer process in highly unsteady turbulent flow field. The fluctuating root mean square velocities in the streamwise as well as in the wall normal direction have been discussed in the present work. It has been found that Partially-Averaged Navier–Stokes (PANS) model is capable of capturing the properties of highly unsteady turbulent flows and gives better results than Reynolds-Averaged Navier–Stokes (RANS). The results obtained using Partially-Averaged Navier–Stokes (PANS) are quite comparable with Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) data available in literature. The partially-averaged Navier–Stokes results are compared with our simulated Reynolds-Averaged Navier–Stokes (RANS) results, available experimental as well as numerical results in literature and it is found to be good in agreement.

On Direct Numerical Simulation of Turbulent Flows

2011 ◽  
Vol 64 (2) ◽  
Author(s):  
Giancarlo Alfonsi
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
High Performance Computing ◽  
Turbulent Flows ◽  
High Performance ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Turbulent Shear ◽  
Navier Stokes Equations ◽  
Performance Computing

The direct numerical simulation of turbulence (DNS) has become a method of outmost importance for the investigation of turbulence physics, and its relevance is constantly growing due to the increasing popularity of high-performance-computing techniques. In the present work, the DNS approach is discussed mainly with regard to turbulent shear flows of incompressible fluids with constant properties. A body of literature is reviewed, dealing with the numerical integration of the Navier-Stokes equations, results obtained from the simulations, and appropriate use of the numerical databases for a better understanding of turbulence physics. Overall, it appears that high-performance computing is the only way to advance in turbulence research through the front of the direct numerical simulation.

scholarly journals Numerical stability analysis of a vortex ring with swirl

2019 ◽  
Vol 878 ◽  
pp. 5-36 ◽  
Author(s):  
Yuji Hattori ◽  
Francisco J. Blanco-Rodríguez ◽  
Stéphane Le Dizès
Keyword(s):  
Numerical Simulation ◽  
Growth Rate ◽  
Direct Numerical Simulation ◽  
Vortex Ring ◽  
Stokes Equations ◽  
Base Flow ◽  
Critical Layer ◽  
Navier Stokes ◽  
Instability Mode ◽  
Navier Stokes Equations

The linear instability of a vortex ring with swirl with Gaussian distributions of azimuthal vorticity and velocity in its core is studied by direct numerical simulation. The numerical study is carried out in two steps: first, an axisymmetric simulation of the Navier–Stokes equations is performed to obtain the quasi-steady state that forms a base flow; then, the equations are linearized around this base flow and integrated for a sufficiently long time to obtain the characteristics of the most unstable mode. It is shown that the vortex rings are subjected to curvature instability as predicted analytically by Blanco-Rodríguez & Le Dizès (J. Fluid Mech., vol. 814, 2017, pp. 397–415). Both the structure and the growth rate of the unstable modes obtained numerically are in good agreement with the analytical results. However, a small overestimation (e.g. 22 % for a curvature instability mode) by the theory of the numerical growth rate is found for some instability modes. This is most likely due to evaluation of the critical layer damping which is performed for the waves on axisymmetric line vortices in the analysis. The actual position of the critical layer is affected by deformation of the core due to the curvature effect; as a result, the damping rate changes since it is sensitive to the position of the critical layer. Competition between the curvature and elliptic instabilities is also investigated. Without swirl, only the elliptic instability is observed in agreement with previous numerical and experimental results. In the presence of swirl, sharp bands of both curvature and elliptic instabilities are obtained for $\unicode[STIX]{x1D700}=a/R=0.1$, where $a$ is the vortex core radius and $R$ the ring radius, while the elliptic instability dominates for $\unicode[STIX]{x1D700}=0.18$. New types of instability mode are also obtained: a special curvature mode composed of three waves is observed and spiral modes that do not seem to be related to any wave resonance. The curvature instability is also confirmed by direct numerical simulation of the full Navier–Stokes equations. Weakly nonlinear saturation and subsequent decay of the curvature instability are also observed.

PANS Turbulence Model for Seamless Transition Between RANS and LES: Fixed-Point Analysis and Preliminary Results

2003 ◽  
Author(s):  
Sharath S. Girimaji ◽  
Ravi Srinivasan ◽  
Euhwan Jeong
Keyword(s):  
Fixed Point ◽  
Navier Stokes ◽  
Control Parameters ◽  
Preliminary Results ◽  
Point Analysis ◽  
Large Eddy ◽  
Seamless Transition ◽  
Bridging Model ◽  
Reynolds Averaged Navier Stokes ◽  
Initial Results

Partially-averaged Navier-Stokes (PANS) approach has been recently developed as a possible bridging model between Reynolds-averaged Navier-Stokes (RANS) method and large-eddy simulations (LES). The resolution control parameters in PANS are the fractions of unresolved kinetic energy (fk) and unresolved dissipation (fε). We investigate the fixed-point behavior of PANS and present some preliminary results obtained using this model. By comparing the fixed-point behavior of PANS and URANS (unsteady Reynolds-averaged Navier-Stokes) methods, the possible advantage of the former over the latter is explained. Initial results from two-dimensional simulations of flow past square results are also presented.

A high-resolution Navier–Stokes solver for direct numerical simulation of free shear flow

2018 ◽  
Vol 74 (6) ◽  
pp. 840-860 ◽  
Author(s):  
Sagar Dave ◽  
Chetankumar Anghan ◽  
Shaswat Saincher ◽  
Jyotirmay Banerjee
Keyword(s):  
Numerical Simulation ◽  
High Resolution ◽  
Shear Flow ◽  
Direct Numerical Simulation ◽  
Navier Stokes
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