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TWiki> CfdTm Web>TestCaseAddNew>TestCase040>TestCase040Res000 (2012-12-12, JacquesFontaine)

TWiki> CfdTm Web>TestCaseAddNew>TestCase040>TestCase040Res000 (2012-12-12, JacquesFontaine)

*Version:* 2.0-beta2

*Authors:* E. Moreau

- In the first configuration, three simulations (laminar) have been performed:

1 idtvar = 0 and iphydr = 1

2 idtvar = 0 and iphydr = 0

3 idtvar = -1 and iphydr = 1

- In the second configuration, we use a %$k-\varepsilon$% model with tilted head losses with respect to the channel axis. In this case the head losses tensor is diagonal. Both the influence of the gradient calculation (IMRGRA) and of iphydr are studied. The angle %$\alpha$% used is of %$\pi/3$%: as a consequence, the fluid must undergoes a deviation of %$\pi/6$%.

- The third configuration allows also an analytical study of the head losses. The mesh undergoes two rotations of angle %$\pi /6$% with respect to Oy then Oz.

Data are stored in two columns; the first is the distance on Ox axis (m) the second is:

- The pressure (Pa) for cas1_P.dat
- The Velocity (m/s) for cas1_V.dat

And results given by the cases models are classed in vertical by 'index' (separate by two new lines) as below :

- index 0: "Axial velocity (m/s) : iphydr=1"
- index 1: "Axial velocity (m/s) : iphydr=1"
- index 2: "Axial velocity (m/s) : iphydr=1"
- index 3: "Axial velocity (m/s) : iphydr=1"

The simulations show that we recover results of the previous version 1.3.1 from a qualitative and analytical point of view.

First and third configurations

- The results are presented on two graphs below. We can see that:

o The option iphydr = 1 allows to recover the accurate value of the head losses: %$\Delta P = 10 000~\rm{Pa}$%.

o The cases idtvar = 0 and idtvar = -1 yield the same results.

o The same jumps as for the version 1.3 are generated on the velocity field for iphydr = 0.

o The error on the pressure jump, for iphydr = 0, is of 0.18% for the version 1.3 against 0.64% for the 2.0

But:

o Contrary to the version 1.3, the version 2.0 does not present any divergence when the option IMRGRA = 3 is activated (probably due to bug fixes in the extended neighborhood handling). Moreover we recover similar results for IMRGRA = 0 and IMRGRA = 3.

o Il should be noted that the third configuration, with extra diagonal term in the head losses tensor, leads to an error in the stationary case (idtvar = -1). Hence the results presented here concerning this case have been done with a constant time step (idtvar = 0).

**Gnuplot Error:**

"/tmp/cas1P.gnu", line 12: warning: Warning - difficulty fitting plot titles into key

The results are given figures (1) to (3). Only a qualitative analysis is done. The results are conform to those expected, and we recover on figure (3) the global shape obtained with the version 1.3.1.

Figure 1 - Pressure field (second configuration).

Figure 2 - Velocity field (second configuration).

Figure 3 - Velocity vectors (second configuration).

It should be noted that a simulation without using the xml file have been performed (we have used only the fortrans files) for the first configuration (laminar). We recover exactly the same results.

I | Attachment | Action | Size | Date | Who | Comment |
---|---|---|---|---|---|---|

dat | cas1_P.dat | manage | 4.5 K | 2010-09-23 - 08:47 | JacquesFontaine | cas1Pdata |

dat | cas1_V.dat | manage | 3.7 K | 2010-09-23 - 08:47 | JacquesFontaine | cas1Vdata |

gz | mesh.tar.gz | manage | 192.0 K | 2010-09-23 - 14:48 | JacquesFontaine | meshes |

jpg | ptot.jpg | manage | 17.8 K | 2010-09-23 - 15:26 | JacquesFontaine | pdcconf2 |

jpg | speed.jpg | manage | 21.4 K | 2010-09-23 - 15:26 | JacquesFontaine | pdcconf2speed |

jpg | speedvect1.jpg | manage | 55.2 K | 2010-09-23 - 15:49 | JacquesFontaine | pdcconf2speedvect |

Topic revision: r37 - 2012-12-12 - 17:29:50 - JacquesFontaine

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