Simulations of Channel Flows With Effects of Spanwise Rotation or Wall Injection Using a Reynolds Stress Model

2000 ◽  
Vol 123 (1) ◽  
pp. 2-10 ◽  
Author(s):  
Bruno Chaouat
Keyword(s):  
Experimental Data ◽  
Reynolds Stress ◽  
Reynolds Stress Model ◽  
Channel Flows ◽  
Fluid Injection ◽  
Turbulent Regime ◽  
Stress Model ◽  
Mean Velocity ◽  
Wall Injection ◽  
Spanwise Rotation

Simulations of channel flows with effects of spanwise rotation and wall injection are performed using a Reynolds stress model. In this work, the turbulent model is extended for compressible flows and modified for rotation and permeable walls with fluid injection. Comparisons with direct numerical simulations or experimental data are discussed in detail for each simulation. For rotating channel flows, the second-order turbulence model yields an asymmetric mean velocity profile as well as turbulent stresses quite close to DNS data. Effects of spanwise rotation near the cyclonic and anticyclonic walls are well observed. For the channel flow with fluid injection through a porous wall, different flow developments from laminar to turbulent regime are reproduced. The Reynolds stress model predicts the mean velocity profiles, the transition process and the turbulent stresses in good agreement with the experimental data. Effects of turbulence in the injected fluid are also investigated.

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.

scholarly journals Rotating Flow and Heat Transfer in Cylindrical Cavities With Radial Inflow

2012 ◽  
Author(s):  
B. G. Vinod Kumar ◽  
John W. Chew ◽  
Nicholas J. Hills
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Reynolds Stress ◽  
Integral Method ◽  
Eddy Viscosity ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Rotating Disc ◽  
Flow And Heat Transfer ◽  
Viscosity Models

Design and optimization of an efficient internal air system of a gas turbine requires thorough understanding of the flow and heat transfer in rotating disc cavities. The present study is devoted to numerical modelling of flow and heat transfer in a cylindrical cavity with radial inflow and comparison with the available experimental data. The simulations are carried out with axi-symmetric and 3-D sector models for various inlet swirl and rotational Reynolds numbers upto 2.1×106. The pressure coefficients and Nusselt numbers are compared with the available experimental data and integral method solutions. Two popular eddy viscosity models, the Spalart-Allmaras and the k-ε, and a Reynolds stress model have been used. For cases with particularly strong vortex behaviour the eddy viscosity models show some shortcomings with the Spalart-Allmaras model giving slightly better results than the k-ε model. Use of the Reynolds stress model improved the agreement with measurements for such cases. The integral method results are also found to agree well with the measurements.

Reynolds Stress Model in the Prediction of Confined Turbulent Swirling Flows

2006 ◽  
Vol 128 (6) ◽  
pp. 1377-1382 ◽  
Author(s):  
Ali M. Jawarneh ◽  
Georgios H. Vatistas
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Reynolds Stress ◽  
Tangential Velocity ◽  
Radial Pressure ◽  
Reynolds Stress Model ◽  
Swirling Flows ◽  
Stress Model ◽  
Swirl Number ◽  
Pressure Profiles

Strongly swirling vortex chamber flows are examined experimentally and numerically using the Reynolds stress model (RSM). The predictions are compared against the experimental data in terms of the pressure drop across the chamber, the axial and tangential velocity components, and the radial pressure profiles. The overall agreement between the measurements and the predictions is reasonable. The predictions provided by the numerical model show clearly the forced and free vortex modes of the tangential velocity profile. The reverse flow (or back flow) inside the core and near the outlet, known from experiments, is captured by the numerical simulations. The swirl number has been found to have a measurable impact on the flow features. The vortex core size is shown to contract with the swirl number which leads to higher pressure drop, higher peak tangential velocity, and deeper radial pressure profiles near the axis of rotation. The adequate agreement between the experimental data and the simulations using RSM turbulence model provides a valid tool to study further these industrially important swirling flows.

Modeling of Cube Array Roughness: RANS, LES, and DNS

2021 ◽  
Author(s):  
Samuel Altland ◽  
Haosen H. A. Xu ◽  
Xiang I. A. Yang ◽  
Robert Kunz
Keyword(s):  
Reynolds Stress ◽  
Significant Degree ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Mean Velocity ◽  
Flow Features ◽  
Drag Partition ◽  
Flow Phenomena ◽  
Rans Models ◽  
Packing Densities

Abstract Flow over arrays of cubes is an extensively studied model problem for rough wall turbulent boundary layers. While considerable research has been performed in computationally investigating these topologies using DNS and LES, the ability of sublayer-resolved RANS to predict the bulk flow phenomena of these systems is relatively unexplored, especially at low and high packing densities. Here, RANS simulations are conducted on six different packing densities of cubes in aligned and staggered configurations. The packing densities investigated span from what would classically be defined as isolated, up to those in the d-type roughness regime, filling in the gap in the present literature. Three different sublayer-resolved turbulence closure models were tested for each case; a low Reynolds number k-ε model, the Menter k-ω SST model, and a full Reynolds stress model. Comparisons of the velocity fields, secondary flow features, and drag coefficients are made between the RANS results and existing LES and DNS results. There is a significant degree of variability in the performance of the various RANS models across all comparison metrics. However, the Reynolds stress model demonstrated the best accuracy in terms of the mean velocity profile as well as drag partition across the range of packing densities.

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%.

scholarly journals Anisotropy Invariant Reynolds Stress Model and Its Application to Fully Developed Channel Flows

PAMM ◽  
2005 ◽  
Vol 5 (1) ◽  
pp. 537-538
Author(s):  
M. Breuer ◽  
S. Ray ◽  
V. Kumar ◽  
J. Jovanović ◽  
F. Durst
Keyword(s):  
Reynolds Stress ◽  
Reynolds Stress Model ◽  
Channel Flows ◽  
Stress Model

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.

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