FUN3D Juncture Flow Computations Compared with Experimental Data

Rumsey, Christopher L.; Carlson, J. J.; Ahmad, Nashat N.

doi:10.2514/6.2019-0079

Cited by 38 publications

(24 citation statements)

References 19 publications

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“…Table 5 lists the results of a grid convergence study for the fan performance metrics of the APP case. It is done using the approach proposed by the Fluids Engineering Division of the ASME [27,28], with refinements to the evaluation of the fine grid convergence index GCI 21 f ine as proposed by Eca and Hoekstra [29,30]. The solution values listed for the fan mass flow and the fan pressure ratio are normalized with the corresponding values form the engine operating point specifications.…”

Section: Urans Simulation Analysismentioning

confidence: 99%

DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

Stuermer¹

2019

Aerospace

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In the context of an increased focus on fuel efficiency and environmental impact, turbofan engine developments continue towards larger bypass ratio engine designs, with Ultra-High Bypass Ratio (UHBR) engines becoming a likely power plant option for future commercial transport aircraft. These engines promise low specific fuel consumption at the engine level, but the resulting size of the nacelle poses challenges in terms of the installation on the airframe. Thus, their integration on an aircraft requires careful consideration of complex engine–airframe interactions impacting performance, aeroelastics and aeroacoustics on both the airframe and the engine sides. As a partner in the EU funded Clean Sky 2 project ASPIRE, the DLR Institute of Aerodynamics and Flow Technology is contributing to an investigation of numerical analysis approaches, which draws on a generic representative UHBR engine configuration specifically designed in the frame of the project. In the present paper, project results are discussed, which aimed at demonstrating the suitability and accuracy of an unsteady RANS-based engine modeling approach in the context of external aerodynamics focused CFD simulations with the DLR TAU-Code. For this high-fidelity approach with a geometrically fully modeled fan stage, an in-depth study on spatial and temporal resolution requirements was performed, and the results were compared with simpler methods using classical engine boundary conditions. The primary aim is to identify the capabilities and shortcomings of these modeling approaches, and to develop a best-practice for the uRANS simulations as well as determine the best application scenarios.

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Section: Urans Simulation Analysismentioning

confidence: 99%

DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

Stuermer¹

2019

Aerospace

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“…Interested readers are referred to the experimental papers, Kegerise et al [10], Jekins et al [26] and the companion paper, Rumsey et al [11]. An extensive NASA report on the experiment is forthcoming and future test are being planned.…”

Section: Discussionmentioning

confidence: 99%

“…Preliminary results pertaining to CFD sensitivity to parameters including grid resolutions, turbulence models, and wall effects will be explored. Further details on the experimental setup and results can be found in a companion paper by Kegerise et al [10], and further CFD comparisons can be found in Rumsey et al [11].…”

Section: Introductionmentioning

confidence: 99%

Overflow Juncture Flow Computations Compared with Experimental Data

Lee¹,

Pulliam

2019

AIAA Scitech 2019 Forum

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NASA's Transformational Tools and Technologies Project (T 3) is supporting a substantial effort to investigate the formation and origin of separation bubbles found on wing-body juncture zones: the Juncture Flow experiment. The first phase of the Juncture Flow experiment, performed in NASA Langley's 14-by 22-Foot Subsonic Tunnel, has been completed. This paper documents the CFD analysis done in conjunction with the experiment. Comparisons between CFD simulations and wind tunnel experimental results will be shown. Oil flow results, surface pressure cuts, velocity profiles, and Reynolds stress profiles will be compared. Preliminary results analyzing the effect of grid resolution, wind tunnel walls, and turbulence models on the above data will be presented. The results are not meant to be a validation study, but more as an evaluation of the current status of Reynolds averaged Navier Stokes (RANS) CFD simulations.

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“…After these seminal studies, many nonlinear RANS models have been proposed, the most common being quadratic [17,19,27,31,32,37] and cubic models [2]. Nonlinear eddy viscosity models have been successfully used to reproduce turbulent secondary flows in different geometries such as non-circular ducts [13,32,33], wing-body junction [3,28,41], turbine-hub flow [38], and to recreate the spanwise rollers in Couette flow [34].…”

Section: Modesti (B)mentioning

confidence: 99%

A priori tests of eddy viscosity models in square duct flow

Modesti

2020

Theor. Comput. Fluid Dyn.

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We carry out a priori tests of linear and nonlinear eddy viscosity models using direct numerical simulation (DNS) data of square duct flow up to friction Reynolds number $${\text {Re}}_\tau =1055$$ Re τ = 1055 . We focus on the ability of eddy viscosity models to reproduce the anisotropic Reynolds stress tensor components $$a_{ij}$$ a ij responsible for turbulent secondary flows, namely the normal stress $$a_{22}$$ a 22 and the secondary shear stress $$a_{23}$$ a 23 . A priori tests on constitutive relations for $$a_{ij}$$ a ij are performed using the tensor polynomial expansion of Pope (J Fluid Mech 72:331–340, 1975), whereby one tensor base corresponds to the linear eddy viscosity hypothesis and five bases return exact representation of $$a_{ij}$$ a ij . We show that the bases subset has an important effect on the accuracy of the stresses and the best results are obtained when using tensor bases which contain both the strain rate and the rotation rate. Models performance is quantified using the mean correlation coefficient with respect to DNS data $${\widetilde{C}}_{ij}$$ C ~ ij , which shows that the linear eddy viscosity hypothesis always returns very accurate values of the primary shear stress $$a_{12}$$ a 12 ($${\widetilde{C}}_{12}>0.99$$ C ~ 12 > 0.99 ), whereas two bases are sufficient to achieve good accuracy of the normal stress and secondary shear stress ($${\widetilde{C}}_{22}=0.911$$ C ~ 22 = 0.911 , $${\widetilde{C}}_{23}=0.743$$ C ~ 23 = 0.743 ). Unfortunately, RANS models rely on additional assumptions and a priori analysis carried out on popular models, including k–$$\varepsilon $$ ε and $$v^2$$ v 2 –f, reveals that none of them achieves ideal accuracy. The only model based on Pope’s expansion which approaches ideal performance is the quadratic correction of Spalart (Int J Heat Fluid Flow 21:252–263, 2000), which has similar accuracy to models using four or more tensor bases. Nevertheless, the best results are obtained when using the linear correction to the $$v^2$$ v 2 –f model developed by Pecnik and Iaccarino (AIAA Paper 2008-3852, 2008), although this is not built on the canonical tensor polynomial as the other models.

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FUN3D Juncture Flow Computations Compared with Experimental Data

Cited by 38 publications

References 19 publications

DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

DLR TAU-Code uRANS Turbofan Modeling for Aircraft Aerodynamics Investigations

Overflow Juncture Flow Computations Compared with Experimental Data

A priori tests of eddy viscosity models in square duct flow

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