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=HiFi-TURB-DLR rounded step=
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= Abstract =
= Abstract =
The present test case was designed to investigate the effect of an adverse pressure gradient on a turbulent boundary layer. The problem considers the flow over a 2D smooth bump geometry, see, Fig. 1, defined at ''UFR_X-YZ_Test_Case'' and inspired by the axisymmetric one proposed by Disotell and Rumsey [1,2,3].
The HiFi-TURB-DLR rounded step test case is designed to investigate the effect of an adverse pressure gradient on a turbulent boundary layer. The problem considers the flow over a 2D planar rounded step, see [[DNS_1-5_#figure1|Fig. 1]], and is inspired by the axisymmetric rounded step proposed by Disotell and Rumsey, see [[DNS_1-5#1|Disotell ''et al.'']], [[DNS_1-5#2|Disotell ''et al.'' (2017)]] and  [[DNS_1-5#3|Alaya ''et al.'' (2021)]].


At the inlet a Blasius profile with Re_x=650000 for the velocity, a uniform profile for static pressure and uniform profile for total temperature are imposed. Transition to turbulence is promoted downstream by means of a local forcing term. At the outlet, a standard Dirichlet condition for the pressure is prescribed. At the upper boundary a freestream condition is set. The Reynolds number is Re= 78490 and is based on freestream properties and bump height. The flow is considered compressible with Mach number based on freestream properties equal to Ma=0.13455.
This test case concerns an under-resolved Direct Numerical Simulation (uDNS) using the high-order discontinuous Galerkin (DG) code MIGALE, see [[DNS_1-5#4|Bassi ''et al.'' (2016)]]. The code couples the DG space discretization with a high-order implicit time integration, which relies on Rosenbrock schemes.
 
The dataset concerns the scale-resolving simulation of the turbulent flow over a smooth bump using the high-order discontinuous Galerkin (DG) code MIGALE [4]. The code couples the high-order DG spatial discretization with high-order implicit time integration using Rosenbrock-type schemes, here of the fifth order [5,6].  
The primary objective of this contribution is to provide a rich database of flow and turbulence statistics as a reference target for verification and validation of RANS models (see [[UFR 3-36 Test Case|UFR 3-36 Test Case]]).
The primary objective of this contribution is to provide a rich database of flow and turbulence statistics for verification and validation on subsequent computational campaigns.  


The provided statistical quantities in the database are:
The provided statistical quantities in the database are:
* mean pressure, temperature, density and velocity components;
* mean pressure and velocity components;
* Favre averaged velocity and temperature;
* mean shear stress and heat flux;
* Reynolds stress components;
* Reynolds stress components;
* pressure, temperature and density autocorrelations;
* Favre velocity triple correlation;
* pressure-velocity correlation;
* Reynolds stress equations budget terms;
* Taylor microscale;
* Taylor microscale;
* Kolmogorov length and time scales;
* Kolmogorov length and time scales;


''WIP …
As the solver discretizes the compressible Navier-Stokes equations, density and temperature fields, as well their gradients, have been collected during the computational campaign. However, since the flow regime is incompressible (<math>{Ma=0.13455}</math>), these fields are a side product of this contribution and thus are not reported.
* shear stress-velocity correlation;
 
* Difference between the Renynolds and the Favre average.''


<div id="figure1"></div>
<div id="figure1"></div>
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|[[Image:smooth_bump_tc01_instantaneous_streamwise_velocity.png|740px]]
|[[Image:smooth_bump_tc01_instantaneous_streamwise_velocity.png|740px]]
|-
|-
|'''Figure 1:''' Smooth bump case, Re=78490. Dimensionless instantaneous streamwise velocity at midspan using MIGALE with DG P3 (~300 million DoF/eqn).
|'''Figure 1:''' HiFi-TURB-DLR rounded step, Re=78,490. Dimensionless instantaneous streamwise velocity at midspan using MIGALE with DG P3 (~300 million DoF/eqn).
|}
|}


University of Bergamo acknowledges PRACE for awarding the access to JUWELS hosted by GCS at FZJ, Germany.


==References==
==References==


[1] K. J. Disotell and C. L. Rumsey, "Modern CFD validation of turbulent flow separation on axisymmetric afterbodies"
#<div id="1">'''Disotell, K. J. and Rumsey, C. L.''': Modern CFD validation of turbulent flow separation on axisymmetric afterbodies.</div>
 
#<div id="2">'''Disotell, K. J. and Rumsey, C. L. (2017)''': Development of an axisymmetric afterbody test case for turbulent flow separation validation. ''NASA/TM-2017219680'', Langley Research Center, Hampton, Virginia</div>
[2] K. J. Disotell and C. L. Rumsey, "Development of an axisymmetric afterbody test case for turbulent flow separation validation", NASA/TM-2017219680, Langley Research Center, Hampton, Virginia, 2017
#<div id="3">'''Alaya, E., Grabe, C. and Knopp, T. (2021)''': Design of a parametrized numerical experiment for a 2D turbulent boundary layer flow with varying adverse pressure gradient and separation behaviour. ''DLR-IB-AS-GO-2020-109'', DLR-Interner Bericht, DLR Institute of Aerodynamics and Flow Technology</div>
 
#<div id="4">'''Bassi, F., Botti, L., Colombo, A. C, Ghidoni, A. and Massa, F. (2016)''': On the development of an implicit high-order Discontinuous Galerkin method for DNS and implicit LES of turbulent flows. ''European Journal of Mechanics, B/Fluids'', Vol. 55(2), pp. 367-379</div>
[3] E. Alaya, C. Grabe, T. Knopp, "Design of a parametrized numerical experiment for a 2D turbulent boundary layer flow with varying adverse pressure gradient and separation behaviour", DLR-Interner Bericht. DLR-IB-AS-GO-2020-109. DLR Institute of Aerodynamics and Flow Technology, 2021
 
[4] Bassi, F., Botti, L., Colombo, A. C, Ghidoni, A., Massa, F., "On the development of an implicit high-order Discontinuous Galerkin method for DNS and implicit LES of turbulent flows”, European Journal of Mechanics, B/Fluids, 2016
 
[5] Di Marzo, G., “RODAS5(4) - Méthodes de Rosenbrock d'ordre 5(4) adaptées aux problèmes différentiels-algébriques", MSc Mathematics Thesis, Faculty of Science, University of Geneva, 1993


[6] Bassi, F., Botti, L., Colombo, A., Ghidoni, A., Massa, F., “Linearly implicit Rosenbrock-type Runge-Kutta schemes applied to the Discontinuous Galerkin solution of compressible and incompressible unsteady flows”, Computers and Fluids, 2015


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|organisation=Università degli studi di Bergamo (UniBG)
|organisation=Università degli studi di Bergamo (UniBG)
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Latest revision as of 16:09, 17 February 2023

HiFi-TURB-DLR rounded step

Front Page

Description

Computational Details

Quantification of Resolution

Statistical Data

Instantaneous Data

Storage Format


Abstract

The HiFi-TURB-DLR rounded step test case is designed to investigate the effect of an adverse pressure gradient on a turbulent boundary layer. The problem considers the flow over a 2D planar rounded step, see Fig. 1, and is inspired by the axisymmetric rounded step proposed by Disotell and Rumsey, see Disotell et al., Disotell et al. (2017) and Alaya et al. (2021).

This test case concerns an under-resolved Direct Numerical Simulation (uDNS) using the high-order discontinuous Galerkin (DG) code MIGALE, see Bassi et al. (2016). The code couples the DG space discretization with a high-order implicit time integration, which relies on Rosenbrock schemes.

The primary objective of this contribution is to provide a rich database of flow and turbulence statistics as a reference target for verification and validation of RANS models (see UFR 3-36 Test Case).

The provided statistical quantities in the database are:

  • mean pressure and velocity components;
  • Reynolds stress components;
  • Taylor microscale;
  • Kolmogorov length and time scales;

As the solver discretizes the compressible Navier-Stokes equations, density and temperature fields, as well their gradients, have been collected during the computational campaign. However, since the flow regime is incompressible (), these fields are a side product of this contribution and thus are not reported.


Smooth bump tc01 instantaneous streamwise velocity.png
Figure 1: HiFi-TURB-DLR rounded step, Re=78,490. Dimensionless instantaneous streamwise velocity at midspan using MIGALE with DG P3 (~300 million DoF/eqn).

University of Bergamo acknowledges PRACE for awarding the access to JUWELS hosted by GCS at FZJ, Germany.

References

  1. Disotell, K. J. and Rumsey, C. L.: Modern CFD validation of turbulent flow separation on axisymmetric afterbodies.
  2. Disotell, K. J. and Rumsey, C. L. (2017): Development of an axisymmetric afterbody test case for turbulent flow separation validation. NASA/TM-2017219680, Langley Research Center, Hampton, Virginia
  3. Alaya, E., Grabe, C. and Knopp, T. (2021): Design of a parametrized numerical experiment for a 2D turbulent boundary layer flow with varying adverse pressure gradient and separation behaviour. DLR-IB-AS-GO-2020-109, DLR-Interner Bericht, DLR Institute of Aerodynamics and Flow Technology
  4. Bassi, F., Botti, L., Colombo, A. C, Ghidoni, A. and Massa, F. (2016): On the development of an implicit high-order Discontinuous Galerkin method for DNS and implicit LES of turbulent flows. European Journal of Mechanics, B/Fluids, Vol. 55(2), pp. 367-379




Contributed by: Francesco Bassi, Alessandro Colombo, Francesco Carlo Massa — Università degli studi di Bergamo (UniBG)

Front Page

Description

Computational Details

Quantification of Resolution

Statistical Data

Instantaneous Data

Storage Format


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