# [GAMBIT] decreasing computational domain

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 April 16, 2015, 17:00 decreasing computational domain #1 Senior Member   Aja Join Date: Nov 2013 Location: Iran Posts: 492 Rep Power: 10 Hi, I am modeling a wells turbine and I have a question. Turbine have 6 blades.((360/6)=60 deg=angle between blades) Due to the circumferential symmetry, only one sixth of the annulus has been computed, imposing periodic boundary conditions in the tangential direction. The computational domain has been restricted in the axial direction to six chord lengths upstream and ten chord lengths downstream of the blade. Fig. 1: Now, we can to decrease angle(fig. 4) until computational domain reduce. Is this work true? For example, instead of angle of 30 deg, we use angle of 20 deg until computational domain reduce.Is this work true? With performing this work, Are solutions of analysis good in fluent? Fig. 2: Fig. 3: Fig. 4: Fig. 5......((30 deg))) Fig. 6:

 April 18, 2015, 15:02 #2 Senior Member   Aja Join Date: Nov 2013 Location: Iran Posts: 492 Rep Power: 10 Can no one guide?

 April 20, 2015, 02:15 #3 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,291 Rep Power: 36 If your geometry looks like the one in fig 2; then the only solution for decreasing computationals cost is your figure 3. Indeed by apllying periodicity you can afford to compute your domain with 360/6 = 60° slice. I you use fig. 5 with 30° slice, and you apply periodicity, then you are computing 360/30=12 blades turbine aja1345 likes this. __________________ In memory of my friend Hervé: CFD engineer & freerider