Improved Prediction of Turbomachinery Flows Using Near-Wall Reynolds-Stress Model

2001 ◽  
Author(s):  
G. A. Gerolymos ◽  
J. Neubauer ◽  
V. C. Sharma ◽  
I. Vallet
Keyword(s):  
Experimental Data ◽  
Turbulent Flows ◽  
Reynolds Stress ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Flow Equations ◽  
Near Wall

In this paper an assessment of the improvement in the prediction of complex turbomachinery flows using a new near-wall Reynolds-stress model is attempted. The turbulence closure used is a near-wall low-turbulence-Reynolds-number Reynolds-stress model, that is independent of the distance-from-the-wall and of the normal-to-the-wall direction. The model takes into account the Coriolis redistribution effect on the Reynolds-stresses. The 5 mean flow equations and the 7 turbulence model equations are solved using an implicit coupled O(Δx3) upwind-biased solver. Results are compared with experimental data for 3 turbomachinery configurations: the ntua high subsonic annular cascade, the nasa_37 rotor, and the rwth 1½ stage turbine. A detailed analysis of the flowfield is given. It is seen that the new model that takes into account the Reynolds-stress anisotropy substantially improves the agreement with experimental data, particularly for flows with large separation, while being only 30% more expensive than the k – ε model (thanks to an efficient implicit implementation). It is believed that further work on advanced turbulence models will substantially enhance the predictive capability of complex turbulent flows in turbomachinery.

Improved Prediction of Turbomachinery Flows Using Near-Wall Reynolds-Stress Model

2001 ◽  
Vol 124 (1) ◽  
pp. 86-99 ◽  
Author(s):  
G. A. Gerolymos ◽  
J. Neubauer ◽  
V. C. Sharma ◽  
I. Vallet
Keyword(s):  
Experimental Data ◽  
Turbulent Flows ◽  
Reynolds Stress ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
Flow Equations ◽  
Near Wall

In this paper an assessment of the improvement in the prediction of complex turbomachinery flows using a new near-wall Reynolds-stress model is attempted. The turbulence closure used is a near-wall low-turbulence-Reynolds-number Reynolds-stress model, that is independent of the distance-from-the-wall and of the normal-to-the-wall direction. The model takes into account the Coriolis redistribution effect on the Reynolds-stresses. The five mean flow equations and the seven turbulence model equations are solved using an implicit coupled OΔx3 upwind-biased solver. Results are compared with experimental data for three turbomachinery configurations: the NTUA high subsonic annular cascade, the NASA_37 rotor, and the RWTH 1 1/2 stage turbine. A detailed analysis of the flowfield is given. It is seen that the new model that takes into account the Reynolds-stress anisotropy substantially improves the agreement with experimental data, particularily for flows with large separation, while being only 30 percent more expensive than the k−ε model (thanks to an efficient implicit implementation). It is believed that further work on advanced turbulence models will substantially enhance the predictive capability of complex turbulent flows in turbomachinery.

Robust Implicit Multigrid Reynolds-Stress Model Computation of 3-D Turbomachinery Flows

2006 ◽  
Author(s):  
G. A. Gerolymos ◽  
I. Vallet
Keyword(s):  
Reynolds Stress ◽  
Time Integration ◽  
Computational Cost ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Finite Volume Scheme ◽  
Stress Model ◽  
Mean Flow ◽  
Approximate Factorization ◽  
Flow Equations

The purpose of this paper is to present a numerical methodology for the computation of complex 3-D turbomachinery flows using advanced multiequation turbulence closures, including full 7-equation Reynolds-stress transport models. A general frame-work describing the turbulence models and possible future improvements is presented. The flow equations are discretized on structured multiblock grids, using an upwind biased (O[Δx3] MUSCL reconstruction) finite-volume scheme. Time-integration uses a local-dual-time-stepping implicit procedure, with internal subiterations. Computational efficiency is achieved by a specific approximate factorization of the implicit subiterations, designed to minimize the computational cost of the turbulence-transport-equations. Convergence is still accelerated using a mean-flow-multigrid full-approximation-scheme method, where multigrid is applied on the mean-flow-variables only. Speed-ups of a factor 3 are obtained using 3 levels of multigrid (fine + 2 coarser grids). Computational examples are presented using several Reynolds-stress model variants (and also a baseline k–ε model), for various turbomachinery configurations, and compared with available experimental measurements.

An explicit algebraic Reynolds stress model for incompressible and compressible turbulent flows

2000 ◽  
Vol 403 ◽  
pp. 89-132 ◽  
Author(s):  
STEFAN WALLIN ◽  
ARNE V. JOHANSSON
Keyword(s):  
Turbulent Flows ◽  
Reynolds Stress ◽  
Compressible Flows ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Reynolds Stresses ◽  
Mean Flow ◽  
New Developments ◽  
The Individual

Some new developments of explicit algebraic Reynolds stress turbulence models (EARSM) are presented. The new developments include a new near-wall treatment ensuring realizability for the individual stress components, a formulation for compressible flows, and a suggestion for a possible approximation of diffusion terms in the anisotropy transport equation. Recent developments in this area are assessed and collected into a model for both incompressible and compressible three-dimensional wall-bounded turbulent flows. This model represents a solution of the implicit ARSM equations, where the production to dissipation ratio is obtained as a solution to a nonlinear algebraic relation. Three-dimensionality is fully accounted for in the mean flow description of the stress anisotropy. The resulting EARSM has been found to be well suited to integration to the wall and all individual Reynolds stresses can be well predicted by introducing wall damping functions derived from the van Driest damping function. The platform for the model consists of the transport equations for the kinetic energy and an auxiliary quantity. The proposed model can be used with any such platform, and examples are shown for two different choices of the auxiliary quantity.

Development and Application of a Two-Scale Non-Linear Reynolds Stress Turbulence Model

2007 ◽  
Author(s):  
S. Y. Jaw ◽  
R. R. Hwang
Keyword(s):  
Turbulent Flows ◽  
Reynolds Stress ◽  
Turbulence Model ◽  
Dissipation Rate ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Turbulence Scale ◽  
Non Linear ◽  
Algebraic Reynolds Stress Model ◽  
Near Wall

To improve the prediction of turbulent flows, a two-scale, non-linear Reynolds stress turbulence model is proposed in this study. It is known that for the near-wall low-Reynolds number turbulent flows, the Kolmogorov turbulence scale, based on the fluid kinematic viscosity and dissipation rate of turbulent kinetic energy (ν,ε), is the dominant turbulence scale, hence it is adopted to address the viscous effects and the rapid increase of dissipation rate in the near wall region. As a wall is approached, the turbulence scale transits smoothly from turbulent kinetic energy based (k, ε) scale to (ν,ε) scale. The damping functions of the low-Reynolds number models can thus be simplified and the near-wall turbulence characteristics, such as the ε distribution, are correctly reproduced. Furthermore, to improve the prediction of the anisotropic Reynolds stresses for complex flows, a nonlinear algebraic Reynolds stress model is incorporated. The same turbulence scales are adopted in the nonlinear algebraic Reynolds stress model. The developed two-scale non-linear Reynolds stress model is first calibrated with the DNS budgets of two-dimensional channel flows, and then applied to predict the separation flow behind a backward facing step. It is found that the proposed two-scale nonlinear Reynolds stress turbulence model is capable of providing satisfactory results without increasing much computation efforts or causing numerical stability problems.

Aerodynamic Comparison and Validation of RANS, URANS and SAS Simulations of Flat Plate Film-Cooling

2010 ◽  
Author(s):  
Stefan Voigt ◽  
Berthold Noll ◽  
Manfred Aigner
Keyword(s):  
Experimental Data ◽  
Reynolds Stress ◽  
Film Cooling ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
3 Dimensional ◽  
Commercial Code ◽  
Sst Model ◽  
Rans Models

The present paper deals with the detailed numerical simulation of film cooling including conjugate heat transfer. Five different turbulence models are used to simulate a film cooling configuration. The models include three steady and two unsteady models. The steady RANS models are the Shear stress transport (SST) model of Menter, the Reynolds stress model of Speziale, Sarkar and Gatski and a k-ε explicit algebraic Reynolds stress model. The unsteady models are a URANS formulation of the SST model and a scale-adaptive simulation (SAS). The solver used in this study is the commercial code ANSYS CFX 11.0. The results are compared to available experimental data. These data include velocity and turbulence intensity fields in several planes. It is shown that the steady RANS approach has difficulties with predicting the flow field due to the high 3-dimensional unsteadiness. The URANS and SAS simulations on the other hand show good agreement with the experimental data. The deviation from the experimental data in velocity values in the steady cases is about 20% whereas the error in the unsteady cases is below 10%.

Measurements and Predictions of a Highly Turbulent Flowfield in a Turbine Vane Passage

2000 ◽  
Vol 122 (4) ◽  
pp. 666-676 ◽  
Author(s):  
R. W. Radomsky ◽  
K. A. Thole
Keyword(s):  
Kinetic Energy ◽  
Turbulent Flow ◽  
Gas Turbine ◽  
Turbulent Kinetic Energy ◽  
Reynolds Stress ◽  
Complex Geometry ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Mean Flow

As highly turbulent flow passes through downstream airfoil passages in a gas turbine engine, it is subjected to a complex geometry designed to accelerate and turn the flow. This acceleration and streamline curvature subject the turbulent flow to high mean flow strains. This paper presents both experimental measurements and computational predictions for highly turbulent flow as it progresses through a passage of a gas turbine stator vane. Three-component velocity fields at the vane midspan were measured for inlet turbulence levels of 0.6%, 10%, and 19.5%. The turbulent kinetic energy increased through the passage by 130% for the 10% inlet turbulence and, because the dissipation rate was higher for the 19.5% inlet turbulence, the turbulent kinetic energy increased by only 31%. With a mean flow acceleration of five through the passage, the exiting local turbulence levels were 3% and 6% for the respective 10% and 19.5% inlet turbulence levels. Computational RANS predictions were compared with the measurements using four different turbulence models including the k-ε, Renormalization Group (RNG) k-ε, realizable k-ε, and Reynolds stress model. The results indicate that the predictions using the Reynolds stress model most closely agreed with the measurements as compared with the other turbulence models with better agreement for the 10% case than the 19.5% case. [S0098-2202(00)00804-X]

scholarly journals Effects of the Duct Angle and Propeller Location on the Hydrodynamic Characteristics of the Ducted Propeller

2018 ◽  
Vol 11 (22) ◽  
pp. 41
Author(s):  
Mehdi Chamanara ◽  
Hassan Ghassemi ◽  
Manouchehr Fadavie ◽  
Mohammad Aref Ghassemi
Keyword(s):  
Experimental Data ◽  
Reynolds Stress ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Numerical Results ◽  
Navier Stokes ◽  
Hydrodynamic Characteristics ◽  
Stress Model ◽  
Ducted Propeller ◽  
Rans Method

In the present study, the effect of the duct angle and propeller location on the hydrodynamic characteristics of the ducted propeller using Reynolds-Averaged Navier Stokes (RANS) method is reported. A Kaplan type propeller is selected with a 19A duct. The ducted propeller is analyzed by three turbulence models including the k-ε standard, k-ω SST and Reynolds stress model (RSM). The numerical results are compared with experimental data. The effects of the duct angle and the location of the propeller inside the propeller are presented and discussed.

scholarly journals Three-Dimensional Navier-Stokes Computation of Turbine Nozzle Flow With Advanced Turbulence Models

1995 ◽  
Author(s):  
J. Luo ◽  
B. Lakshminarayana
Keyword(s):  
Reynolds Stress ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Nozzle Flow ◽  
Stress Model ◽  
Mean Flow ◽  
The Mean ◽  
Algebraic Reynolds Stress Model

A three-dimensional Navier-Stokes procedure has been used to compute the three-dimensional viscous flow through the turbine nozzle passage of a single stage turbine. A low Reynolds number k-ε model and a zonal k-ε/ARSM (algebraic Reynolds stress model) are utilized for turbulence closure. The algebraic Reynolds stress model is used only in the endwall region to represent the anisotropy of turbulence. A four-stage Runge-Kutta scheme is used for time-integration of both the mean-flow and the turbulence transport equations. For the turbine nozzle flow, comprehensive comparisons between the predictions and the experimental data obtained at Penn State show that most features of the vortex-dominated endwall flow, as well as nozzle wake structure, have been captured well by the numerical procedure. An assessment of the performance of the turbulence models has been carried out The two models are found to provide similar predictions for the mean flow parameters, although slight improvement in the prediction of some secondary flow quantities has been obtained by the ARSM model.

Analysis of Impinging and Countercurrent Stagnating Flows by Reynolds Stress Model

2002 ◽  
Vol 124 (3) ◽  
pp. 706-718 ◽  
Author(s):  
Yong H. Im ◽  
Kang Y. Huh ◽  
Kwang-Yong Kim
Keyword(s):  
Numerical Simulation ◽  
Kinetic Energy ◽  
Turbulent Flows ◽  
Reynolds Stress ◽  
Dissipation Rate ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Stagnation Region

Numerical simulation is performed for stagnating turbulent flows of impinging and countercurrent jets by the Reynolds stress model (RSM). Results are compared with those of the k−ε model and available data to assess the flow characteristics and turbulence models. Three variants of the RSM tested are those of Gibson and Launder (GL), Craft and Launder (GL-CL) and Speziale, Sarkar and Gatski (SSG). As is well known, the k−ε model significantly overestimates turbulent kinetic energy near the wall. Although the RSM is superior to the k−ε model, it shows considerable difference according to how the redistributive pressure-strain term is modeled. Results of the RSM for countercurrent jets are improved with the modified coefficients for the dissipation rate, Cε1 and Cε2, suggested by Champion and Libby. Anisotropic states of the stress near the stagnation region are assessed in terms of an anisotropy invariant map (AIM).

Three-Dimensional Navier–Stokes Computation of Turbine Nozzle Flow With Advanced Turbulence Models

1997 ◽  
Vol 119 (3) ◽  
pp. 516-530 ◽  
Author(s):  
J. Luo ◽  
B. Lakshminarayana
Keyword(s):  
Reynolds Stress ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Navier Stokes ◽  
Nozzle Flow ◽  
Stress Model ◽  
Mean Flow ◽  
The Mean ◽  
Algebraic Reynolds Stress Model

A three-dimensional Navier–Stokes procedure has been used to compute the three-dimensional viscous flow through the turbine nozzle passage of a single-stage turbine. A low-Reynolds-number k–ε model and a zonal k-ε/ARSM (algebraic Reynolds stress model) are utilized for turbulence closure. The algebraic Reynolds stress model is used only in the endwall region to represent the anisotropy of turbulence. A four-stage Runge–Kutta scheme is used for time integration of both the mean-flow and the turbulence transport equations. For the turbine nozzle flow, comprehensive comparisons between the predictions and the experimental data obtained at Penn State show that most features of the vortex-dominated endwall flow, as well as nozzle wake structure, have been captured well by the numerical procedure. An assessment of the performance of the turbulence models has been carried out. The two models are found to provide similar predictions for the mean flow parameters, although slight improvement in the prediction of some secondary flow quantities has been obtained by the ARSM model.

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