Sensitization of the SST Turbulence Model to Rotation and Curvature by Applying the Spalart-Shur Correction Term

2008 ◽  
Author(s):  
Pavel E. Smirnov ◽  
Florian R. Menter
Keyword(s):  
Turbulent Flows ◽  
Turbulence Model ◽  
Transport Model ◽  
Correction Term ◽  
Computational Cost ◽  
Reynolds Stresses ◽  
Wide Range ◽  
Sst Model ◽  
Shear Stress Transport Model ◽  
Sst Turbulence Model

A rotation-curvature correction suggested earlier by Spalart and Shur for the one-equation Spalart-Allmaras turbulence model is adapted to the Shear Stress Transport model. This new version of the model (SST-CC) has been extensively tested on a wide range of both wall-bounded and free shear turbulent flows with system rotation and/or streamline curvature. Predictions of the SST-CC model are compared with available experimental and DNS data, on one hand, and with the corresponding results of the original SST model and advanced Reynolds stresses transport model (RSM), on the other hand. It is found, that in terms of accuracy the proposed model significantly improves the original SST model and is quite competitive with the RSM, whereas its computational cost is significantly less than that of the RSM.

Sensitization of the SST Turbulence Model to Rotation and Curvature by Applying the Spalart–Shur Correction Term

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Pavel E. Smirnov ◽  
Florian R. Menter
Keyword(s):  
Turbulent Flows ◽  
Turbulence Model ◽  
Transport Model ◽  
Correction Term ◽  
Computational Cost ◽  
Turbulence Models ◽  
Reynolds Stress Transport Model ◽  
Wide Range ◽  
Sst Model ◽  
The One

A rotation-curvature correction suggested earlier by Spalart and Shur (1997, “On the Sensitization of Turbulence Models to Rotation and Curvature,” Aerosp. Sci. Technol., 1(5), pp. 297–302) for the one-equation Spalart–Allmaras turbulence model is adapted to the shear stress transport model. This new version of the model (SST-CC) has been extensively tested on a wide range of both wall-bounded and free shear turbulent flows with system rotation and/or streamline curvature. Predictions of the SST-CC model are compared with available experimental and direct numerical simulations (DNS) data, on the one hand, and with the corresponding results of the original SST model and advanced Reynolds stress transport model (RSM), on the other hand. It is found that in terms of accuracy the proposed model significantly improves the original SST model and is quite competitive with the RSM, whereas its computational cost is significantly less than that of the RSM.

Modeling of Turbulent Flows Through the Annular Channel with Eccentricity and Rotating Inner Cilinder

2012 ◽  
Vol 7 (4) ◽  
pp. 79-86
Author(s):  
Evgeny Podryabinkin ◽  
Valeriy Rudyak
Keyword(s):  
Pressure Drop ◽  
Turbulent Flows ◽  
Transport Model ◽  
Reverse Flow ◽  
Axial Flow ◽  
Annular Channel ◽  
Rotational Flow ◽  
Concentric Annulus ◽  
Cylindrical Annulus ◽  
Wide Range

In this paper fully developed turbulent flows of Newtonian fluid in cylindrical annulus with eccentricity and rotating inner cylinder has been systematically studied. Modeling has been performed on the base of Menter Shear Transport model of turbulence in a wide range of Reynolds numbers, eccentricity, and radii ratio. As the result dependencies of flow field and pressure drop along the channel on geometrical and flow parameters have been found. It was shown that flow characteristics and dependence of the pressure drop are determined by which flow axial or rotational dominates and caused generation of turbulence. When rotational flow dominates the dependence of the pressure drop is almost linear. When axial flow dominates rotation practically has no impact on the pressure drop in concentric annulus. Appearance of the reverse flow in eccentric channel has a major impact on the pressure drop. In case when rotational flow dominates, appearance of the reverse flow is accompanied by threshold flow restructuring at some critical value of eccentricity. A correlation for determination of the pressure drop in various regimes has been developed for the case of concentric annulus

scholarly journals EVALUATION OF THE APPLICABILITY OF A TURBULENT WAKE INLET BOUNDARY CONDITION

2017 ◽  
Vol 16 (2) ◽  
pp. 78
Author(s):  
P. A. Soliman ◽  
A. V. de Paula ◽  
A. P. Petry ◽  
S. V. Möller
Keyword(s):  
Stokes Equations ◽  
Transport Model ◽  
Characteristic Length ◽  
Computational Cost ◽  
The Body ◽  
Navier Stokes ◽  
Computational Time ◽  
Flow Forming ◽  
Shear Stress Transport Model ◽  
Grid Convergence Index

With the objective of reducing the computational cost of the iterative processes of aerodynamic components design, tests were carried out to study under what conditions, and with what difference, only part of the calculation domain can be solved using as input information obtained from complete simulations already solved. An experimental study of an airfoil exposed to the wake interference of an upstream airfoil at a Reynolds number of 150,000 was used to verify the solutions of the Reynolds-Averaged Navier-Stokes equations solved applying the k-ω Shear Stress Transport model for turbulence closure. A Grid Convergence Index study was performed to verify if the solution of the equations for the adopted discretization leads to results within the asymptotic range. With the physical coherence of the numerical methodology verified, comparisons between the simulations with the domain comprising the two airfoils and the domain comprising only the downstream airfoil were performed. Computational time reductions in the order of 40% are observed. The differences in the aerodynamic coefficients for the two types of simulation are presented as a function of distances non-dimensionalized by the characteristic length of the body that disturbs the flow forming the wake, showing that the difference between the two methods was inversely proportional to the distance between the two bodies. Behavior that was maintained until a point where the simulation diverges, equivalent to 25% of the characteristic length of the body that generates the wake.

Modification of Shear Stress Transport Turbulence Model Using Helicity for Predicting Corner Separation Flow in a Linear Compressor Cascade

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Yangwei Liu ◽  
Yumeng Tang ◽  
Ashley D. Scillitoe ◽  
Paul G. Tucker
Keyword(s):  
Shear Stress ◽  
Turbulence Model ◽  
Incidence Angle ◽  
Computational Cost ◽  
Separation Flow ◽  
Compressor Cascade ◽  
Production Term ◽  
Corner Separation ◽  
Shear Stress Transport ◽  
Sst Model

Abstract Three-dimensional corner separation significantly affects compressor performance, but turbulence models struggle to predict it accurately. This paper assesses the capability of the original shear stress transport (SST) turbulence model to predict the corner separation in a linear highly loaded prescribed velocity distribution (PVD) compressor cascade. Modifications for streamline curvature, Menter’s production limiter, and the Kato-Launder production term are examined. Comparisons with experimental data show that the original SST model and the SST model with different modifications can predict the corner flow well at an incidence angle of −7 deg, where the corner separation is small. However, all the models overpredict the extent of the flow separation when the corner separation is larger, at an incidence angle of 0 deg. The SST model is then modified using the helicity to take account of the energy backscatter, which previous studies have shown to be important in the corner separation regions of compressors. A Reynolds stress model (RSM) is also used for comparison. By comparing the numerical results with experiments and RSM results, it can be concluded that sensitizing the SST model to helicity can greatly improve the predictive accuracy for simulating the corner separation flow. The accuracy is quite competitive with the RSM, whereas in terms of computational cost and robustness it is superior to the RSM.

Analysis of an Oscillating Wing in a Power-Extraction Regime Based on the Compressible Reynolds-Averaged Navier-Stokes Equations and the K–ω SST Turbulence Model

2013 ◽  
Author(s):  
M. Sergio Campobasso ◽  
Andreas Piskopakis ◽  
Minghan Yan
Keyword(s):  
Turbulent Flow ◽  
Stokes Equations ◽  
Transport Model ◽  
Extraction Process ◽  
Navier Stokes ◽  
Maximum Efficiency ◽  
Power Extraction ◽  
Shear Stress Transport Model ◽  
Sst Turbulence Model ◽  
Reynolds Averaged Navier Stokes

The aerodynamic performance of an oscillating wing device to extract energy from an oncoming air flow is here investigated by means of time-dependent turbulent flow simulations performed with a compressible Reynolds-averaged Navier-Stokes research solver using the k–ω Shear Stress Transport model. Previous studies of this device have focused primarily on laminar flow regimes, and have shown that the maximum aerodynamic power conversion can achieve values of about 34 %. The comparative analyses of the energy extraction process in a realistic turbulent flow regime and an ideal laminar regime, reported for the first time in this article, highlight that a) substantial differences of the flow aerodynamics exist between the two cases, b) the maximum efficiency of the device in turbulent conditions achieves values of nearly 40 %, and c) further improvement of the efficiency observed in turbulent flow conditions is achievable by optimizing the kinematic characteristics of the device. The theory underlying the implementation of the adopted compressible turbulent flow solver, and several novel algorithmic features associated with its strongly coupled explicit multigrid integration of the flow and turbulence equations, are also presented.

Numerical Models of Wind Effects on Temperature Loaded Object

2017 ◽  
Vol 738 ◽  
pp. 69-78
Author(s):  
Vladimira Michalcova ◽  
Lenka Lausova ◽  
Iveta Skotnicova ◽  
Sergej Kuznetsov
Keyword(s):  
Transport Model ◽  
Numerical Models ◽  
Simulation Models ◽  
Lower Atmosphere ◽  
Small Scale ◽  
Ansys Fluent ◽  
Eddy Simulation ◽  
Wide Range ◽  
Shear Stress Transport Model ◽  
The Difference

Wind climate influencing wind loads on buildings and other structures, as well as the dispersion of pollutants from various surfaces is essentially determined by small-scale motions and processes occurring in the atmospheric boundary layer (ABL). The physical and thermal properties of the underlying surface, in conjunction with the dynamics and thermodynamics of the lower atmosphere influence the distribution of wind velocity in thermally stratified ABL. Atmospheric turbulence is characterized by a high degree of irregularity, three-dimensionality, diffusivity, dissipation, and a wide range of motion scales. This article describes a change of selected turbulent variables in the surroundings of flow around a thermally loaded object. The problem is solved numerically in Ansys Fluent 13.0 software using LES (Large eddy simulation) models as well as the Transition SST (Shear Stress Transport) model that is able to take into account the difference between high and low turbulence at the interface between the wake behind an obstacle and the free stream. The results are mutually compared and verified with experimental measurements in the wind tunnel.

An Improved Shear Stress Transport(SST) Model for High Speed Flows

2012 ◽  
Vol 229-231 ◽  
pp. 625-629
Author(s):  
Jing Yuan Liu ◽  
Wen Qiang Cheng
Keyword(s):  
Boundary Layer ◽  
Shear Stress ◽  
Turbulence Model ◽  
High Speed ◽  
Correction Term ◽  
Plate Boundary ◽  
Experimental Results ◽  
Tvd Scheme ◽  
Shear Stress Transport ◽  
Sst Model

An improved Shear Stress Transport(SST) model, which allows for the compressible corrections, is proposed in this study. Numerical scheme was established by taking advantage of the improved Total Variation Diminishing (TVD) scheme and by applying implicit scheme to the negative source terms of the turbulence model. Hypersonic flat-plate boundary-layer flows and hypersonic compression ramp flows marked with separation, reattachment and shock/boundary-layer interactions are then computed. The comparisons between the computational results, the experimental results and the semi-empirical formulations show that the compressible correction term of the SST turbulence model is the scalar product of the weighted density average of the turbulent fluctuating velocity and the pressure gradients of the average flow field correlation quantities. In addition, for flow with separation and without separation, calculation results of wall pressures, friction coefficients and wall heat transfer rate distributions using the improved model and established scheme agree better with the experimental results than that using the original SST model.

Modeling of Turbulent Flows Through the Annular Channel with Eccentricity and Rotating Inner Cilinder

2012 ◽  
Vol 7 (4) ◽  
pp. 79-86
Author(s):  
Evgeny Podryabinkin ◽  
Valeriy Rudyak
Keyword(s):  
Pressure Drop ◽  
Turbulent Flows ◽  
Transport Model ◽  
Reverse Flow ◽  
Axial Flow ◽  
Annular Channel ◽  
Rotational Flow ◽  
Concentric Annulus ◽  
Cylindrical Annulus ◽  
Wide Range

In this paper fully developed turbulent flows of Newtonian fluid in cylindrical annulus with eccentricity and rotating inner cylinder has been systematically studied. Modeling has been performed on the base of Menter Shear Transport model of turbulence in a wide range of Reynolds numbers, eccentricity, and radii ratio. As the result dependencies of flow field and pressure drop along the channel on geometrical and flow parameters have been found. It was shown that flow characteristics and dependence of the pressure drop are determined by which flow axial or rotational dominates and caused generation of turbulence. When rotational flow dominates the dependence of the pressure drop is almost linear. When axial flow dominates rotation practically has no impact on the pressure drop in concentric annulus. Appearance of the reverse flow in eccentric channel has a major impact on the pressure drop. In case when rotational flow dominates, appearance of the reverse flow is accompanied by threshold flow restructuring at some critical value of eccentricity. A correlation for determination of the pressure drop in various regimes has been developed for the case of concentric annulus

Reynolds Stress Turbulence Models for Prediction of Shear Stress Terms in Cross Flow Film Cooling — Numerical Simulation

2002 ◽  
Author(s):  
Aliyar Javadi ◽  
Khodayar Javadi ◽  
Mohamad Taeibi-Rahni ◽  
Mohammad Reza Keimasi
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Reynolds Stress ◽  
Turbulence Model ◽  
Film Cooling ◽  
Model Comparison ◽  
Transport Model ◽  
Staggered Grid ◽  
Computational Domain ◽  
Sst Turbulence Model

Reynolds stress models are computationally more complex and time consuming but, have the potential of greater accuracy and wider applicability. Turbulent cross flows and film cooling have highly complex characteristics. In this work, we computationally simulated a three-dimensional, separated hole film cooling problem of flow over a flat plate, using Reynolds stress model (RSM) with wall function and zonal (κ-ε)/(κ-ω) turbulence model (shear stress transport model or SST). The Reynolds number of the jet was 4700. Our computational domain included the space above plate plus the film cooling jet channel. In our numerical simulation, the SIMPLE finite volume method with a non-uniform staggered grid was implemented. Our results were compared with Ajersch et al. experimental and numerical work’s (κ-ε turbulence model). Also, they were compared with Keimasi and Taeibi-Rahani’s numerical simulation work (SST turbulence model). Comparison between the measured and computed results show, that RSM/SST turbulence model in our work has better agreement with experimental data in most cases.

The determination of turbulence-model statistics from the velocity–acceleration correlation

2014 ◽  
Vol 757 ◽  
Author(s):  
Stephen B. Pope
Keyword(s):  
Turbulent Flows ◽  
Turbulence Model ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Variable Density ◽  
Navier Stokes ◽  
Reynolds Stresses ◽  
Constant Property ◽  
Langevin Model ◽  
High Reynolds

AbstractFor inhomogeneous turbulent flows at high Reynolds number, it is shown that the redistribution term in Reynolds-stress turbulence models can be determined from the velocity–acceleration correlation. It is further shown that the drift coefficient in the generalized Langevin model (which is used in probability density function (PDF) methods) can be determined from the Reynolds stresses and the velocity–acceleration correlation. These observations are valuable, since the second moments of velocity and acceleration can be measured in experiments, in direct numerical simulations and in well-resolved large-eddy simulations (LES), and hence these turbulence-model quantities can be determined. The redistribution is closely related to the pressure–rate-of-strain, and the unknown in the PDF equation is closely related to the conditional mean pressure gradient (conditional on velocity). In contrast to the velocity–acceleration moments, these pressure statistics are much more difficult to obtain, and our knowledge of them is quite limited. It is also shown that the generalized Langevin model can be re-expressed to provide a direct connection between the drift term and the fluid acceleration. All of these results are first obtained using the constant-property Navier–Stokes equations, but it is then shown that the results are simply extended to variable-density flows.

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