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September 5, 2012, 05:58 |
Turning supersonic flow into subsonic
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#1 |
New Member
Alexander
Join Date: Sep 2012
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Hello,
I have a supersonic converging-diverging inlet system using external and internal compression system. My initial flow is Mach 3 and therefore, of course the flow throwout the whole inlet is supersonic. I am trying to achieve a subsonic outlet of the inlet by increasing the pressure outlet. But it doesn't work because in supersonic flows, Fluent doesn't consider outlet pressure. So how can I force the flow to become subsonic even though I can't change the pressure outlet? Thanks |
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September 5, 2012, 08:51 |
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#2 |
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You can not force the outlet to achieve a pressure. Flow regime defines what should happen at the outlet
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Saeed Sadeghi Ansys Fluent CFD Consultant |
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September 5, 2012, 09:08 |
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#3 |
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Alexander
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Thank you for your response.
So what you are saying is that there is no way to receive a supersonic inlet with a subsonic outlet (having a normal shock in the diverging part of the system)? In any way possible? |
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September 5, 2012, 09:34 |
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#4 |
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It depends just on boundary condition (not outlet) and geometry.
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Saeed Sadeghi Ansys Fluent CFD Consultant |
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September 5, 2012, 09:42 |
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#5 |
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Alexander
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What condition do you think should I enter on the outlet? Tried changing it into "pressure inlet" and it didn't help.
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September 5, 2012, 12:17 |
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#6 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
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The problem is that in a supersonic flow, the flow field is not affected by the conditions downstream. Thus, the flow field in a given geometry is independent of the values you try to specify at the outlet.
Your only chance (if the upstream values are fixed) is to change the geometry. |
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September 23, 2012, 10:35 |
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#7 |
New Member
Alexander
Join Date: Sep 2012
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Can someone help me please with this problem?
I've seen few works that managed to apply a high pressure outlet in a supersonic inlet, but couldn't reach the authors. Does anyone know how to enforce it in FLUENT? Thanks |
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September 23, 2012, 21:10 |
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#8 | |
Senior Member
Ehsan Asgari
Join Date: Apr 2010
Posts: 473
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Quote:
I have a similar problem and I couldn't manage to find a solution. There is an image of the geometry and Mach contours that I upload here. How is it possible to get this solution?! Anyone knows it? |
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Tags |
converging, diverging, subsonic, supersonic |
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