UFR 3-36: Difference between revisions

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In contrast to the latter test cases, the UFR described here was designed by the German Aerospace Center (DLR) as a purely numerical test case that cannot be directly transferred to a wind tunnel experiment. The geometry is part of a family of four different geometries, each with two different Reynolds numbers (<math>{Re_H=78490}</math> and <math>{Re_H=136504}</math>) based on the step height H. The objective is to provide a test case suitable for DNS computations to generate a comprehensive database that can be exploited by data-driven approaches employing Machine Learning (ML). The final designs are based on a study applying several state-of-the-art Reynold-Averaged Navier-Stokes (RANS) models as well as on an experimental test case designed by NASA [&#8204;[[Lib:UFR_3-36_References#6|6]]].  
In contrast to the latter test cases, the UFR described here was designed by the German Aerospace Center (DLR) as a purely numerical test case that cannot be directly transferred to a wind tunnel experiment. The geometry is part of a family of four different geometries, each with two different Reynolds numbers (<math>{Re_H=78490}</math> and <math>{Re_H=136504}</math>) based on the step height H. The objective is to provide a test case suitable for DNS computations to generate a comprehensive database that can be exploited by data-driven approaches employing Machine Learning (ML). The final designs are based on a study applying several state-of-the-art Reynold-Averaged Navier-Stokes (RANS) models as well as on an experimental test case designed by NASA [&#8204;[[Lib:UFR_3-36_References#6|6]]].  


From the four different configurations designed for the purpose and the two different Reynolds numbers, only one test case is discussed here. The configuration presents a moderate APG which results in an incipient separation flow in the step region. For this configuration RANS simulations are performed using a Reynolds Stress model by DLR and a two-equation model by the University of Bergamo (UniBg). Additionally, uDNS computations are performed and made availbale by UniBg.  
From the four different configurations designed for the purpose and the two different Reynolds numbers, only one test case is discussed here. The configuration presents a moderate APG which results in an incipient separation flow in the step region. For this configuration RANS simulations are performed using a Reynolds Stress model by DLR and a two-equation model by the University of Bergamo (UniBg). Additionally, uDNS computations are performed and made available by UniBg.  


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Revision as of 10:16, 3 November 2022

HiFi-TURB-DLR rounded step

Front Page

Description

Test Case Studies

Evaluation

Best Practice Advice

References

Semi-confined Flows

Underlying Flow Regime 3-36

Abstract

The Underlying Flow Regime (UFR) studied here, is a Turbulent Boundary layer (TBL) subjected to an adverse pressure gradient (APG) inducing flow separation on a smooth curved surface. The physically and industrially significant flow phenomenon remains challenging to predict with state-of-the-art RANS turbulence models despite the numerous existing experimental and numerical studies. Popular examples are the 2D NASA Wall-mounted Hump of Greenblatt et al. [‌1][‌2] as well as the curved backward facing step [‌3][‌4]. For both cases, experimental data, LES/DNS-data as well as results from RANS turbulence models exist [‌4][‌5].

In contrast to the latter test cases, the UFR described here was designed by the German Aerospace Center (DLR) as a purely numerical test case that cannot be directly transferred to a wind tunnel experiment. The geometry is part of a family of four different geometries, each with two different Reynolds numbers ( and ) based on the step height H. The objective is to provide a test case suitable for DNS computations to generate a comprehensive database that can be exploited by data-driven approaches employing Machine Learning (ML). The final designs are based on a study applying several state-of-the-art Reynold-Averaged Navier-Stokes (RANS) models as well as on an experimental test case designed by NASA [‌6].

From the four different configurations designed for the purpose and the two different Reynolds numbers, only one test case is discussed here. The configuration presents a moderate APG which results in an incipient separation flow in the step region. For this configuration RANS simulations are performed using a Reynolds Stress model by DLR and a two-equation model by the University of Bergamo (UniBg). Additionally, uDNS computations are performed and made available by UniBg.




Contributed by: Erij Alaya and Cornelia Grabe — Deutsches Luft-und Raumfahrt Zentrum (DLR)

Front Page

Description

Test Case Studies

Evaluation

Best Practice Advice

References


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