# Results for case U-bend circular cross section

Code: Code_Saturne

Version: 2.0-beta2

Authors: A. Defossez - D. Sénéchal

## Method and Numerical Options

Different tests have been performed varying several parameters according to the table below. The main objective is to test the influence of the turbulence models on the results. In addition, all calculations have been run with an improved pressure gradient calculation at the wall (EXTRAG=1).
Case Mesh Turb. Model Conv. scheme Parameters Note
CAS1 O-type %$k-\varepsilon$% CD IDEUCH= 2 Test in CCRT
IDTVAR=-1
IMRGRA= 3
CAS2 O-type %$R_{ij}-\varepsilon\,SSG$% CD IDEUCH= 2
IDTVAR=-1
IMRGRA= 3

All calculations have been done the improved pressure extrapolation at the wall (EXTRAG = 1).

## Models

%$k-\varepsilon$%, %$R_{ij}-\varepsilon\,SSG$%

## Mesh

Two meshes have been used in the simulations, one in Simail format and the other in StarCCM + format.

One mesh has been employed in the investigation: a structured O-type mesh with 53664 cells. A visualization of the mesh is presented in Fig. 2

 Fig. 2: Visualisation of the "O-type" mesh

## Description of the results files

Numerical results are compared with experiments [1] at eight different locations (see Fig. 2). The below table reports the xml file, the fortran and the results files.For every single section the file contains:
1. Radial position
2. Stream-wise velocity
3. Radial velocity
4. Angular velocity
5. Pressure
6. Turbulent kinetic energy
7. Dissipation
In order to make dimensionless the radial position the following relation has to be used: %BEGINLATEX{label="eq:RD"}% $$R/D=\left(\cfrac{D}{2}-r\right)\cfrac{1}{D}$$ %ENDLATEX% where %$D$% is the diameter of the pipe.

Table with sources and results
CAS1 xml SRC Results
CAS2 xml SRC Results

 Fig.2 Location of the reference section for the display of the results

## Boundary conditions

Colour Type
10 Inlet
9 Pressure outlet
5 Wall

## Reference Publications

1. Azzola J., Humphrey J.A.C., Developing turbulent flow in a %$180^{o}$% curved pipe and its downstream tangent, Report LBL-17681, Material and Molecular Research Division, Lawrence Berkeley Laboratory, University of California.

Here-below are presented the results for the streamwise velocity on the different sections. We can here see that the results between both versions are quite similar and rather close to the reference points. We can also observed the slight over-prediction of the velocity downwards the elbow.

Compared to the previous validation only one mesh has been tested. The reader will refer to the previous report for more information on results with different meshes.

• udeb1.png:

• udeb2.png:

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Topic attachments
I Attachment Action Size Date Who Comment
xml KEPS_FW_STAT.xml manage 6.9 K 2010-09-22 - 17:49 StefanoRolfo Archive with xml, src and profiles
gz RESU_RijSSG.tar.gz manage 5.9 K 2010-09-22 - 17:49 StefanoRolfo Archive with xml, src and profiles
gz RESU_k-ep.tar.gz manage 5.8 K 2010-09-22 - 17:49 StefanoRolfo Archive with xml, src and profiles
xml Rij_SSG_STAT.xml manage 7.2 K 2010-09-22 - 17:49 StefanoRolfo Archive with xml, src and profiles
gz SRC_RijSSG.tar.gz manage 106.1 K 2010-09-22 - 17:49 StefanoRolfo Archive with xml, src and profiles
gz SRC_kep.tar.gz manage 106.1 K 2010-09-22 - 17:49 StefanoRolfo Archive with xml, src and profiles
gz coude180.des.gz manage 986.4 K 2010-09-22 - 16:54 StefanoRolfo Mesh O-type
png maillage_std.png manage 63.8 K 2010-09-22 - 15:32 StefanoRolfo Mesh O-type
pdf sections.pdf manage 7.1 K 2010-09-22 - 15:30 StefanoRolfo Reference sections for the results
png sections.png manage 8.1 K 2010-09-22 - 15:31 StefanoRolfo Reference sections for the results
png udeb1.png manage 12.5 K 2011-05-11 - 17:52 DavidMonfort
png udeb2.png manage 12.8 K 2011-05-11 - 17:53 DavidMonfort
Topic revision: r26 - 2012-02-23 - 10:51:23 - ParhamMomeni
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09 Dec 2019

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