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-   -   Does Anybody knows what is it? (http://www.cfd-online.com/Forums/fluent/110486-does-anybody-knows-what.html)

paduchev December 12, 2012 06:56

Does Anybody knows what is it?
 
1 Attachment(s)
Does Anybody knows what is it?

Its Fluents calculation. Jey engines nozzle. 2d axisymmetric model
double precision
density based
k-e SST
there are pessure distribution vibrations
What is the error?

Far December 12, 2012 07:09

it is a simulation of By pass and core flow ?

paduchev December 12, 2012 13:44

Quote:

Originally Posted by Far (Post 397124)
it is a simulation of By pass and core flow ?

Yes, It's a simulation of Turbofan Engines nozzle

paduchev December 12, 2012 14:01

Quote:

Originally Posted by paduchev (Post 397200)
Yes, It's a simulation of Turbofan Engines nozzle

I dont know how to get rid of these pseudo little unphysical shock waves

paduchev December 13, 2012 03:38

could it be because of limiter type?

Far December 15, 2012 03:10

How did you model the bypass and core flow?

Will they form the one stream when exiting the domain? Do you have convergent nozzle after the bypass and core flow?

How did you specify the boundary conditions for the core flow and bypass flow?

What is the boundary condition at the outlet of the domain?

Mesh information : mesh type, no of nodes and refinement in the critical areas?

Convergence criteria?

Turbulence model?

Approximation in geometry?

How did you model the mixing?

Please post few pics with mesh, domain etc to clearly see the problem area and then appropriate solution!!!

paduchev December 15, 2012 08:02

3 Attachment(s)
Boundary conditions in Bypass and Core channels where Pressure Inlet ( Total Pressure and Total temperature)
in the outlet of the domain - pressure outlet (static pressure)
convergence criteria - all forces on the nozzle are constant and global disbalances
Turbulence model - k-omega-SST
What do u means about aproximations in geometry?
Mesh - hexa

Far December 15, 2012 09:41

It is mixed type turbofan engine?

I am assuming you have three streams. First one is freestream, second one is bypass and below one is the core flow. Right?

Are they going to mix first and then exit from the propelling nozzle?

PS: I have done the mixed flow turbofan simulation successfully in past

paduchev December 15, 2012 09:43

Quote:

Originally Posted by Far (Post 397673)
It is mixed type turbofan engine?

I am assuming you have three streams. First one is freestream, second one is bypass and below one is the core flow. Right?

Are they going to mix first and then exit from the propelling nozzle?

No, It's separated flow nozzle
two streams - core and fan
and external flow with Mach number 0.8

paduchev December 15, 2012 09:53

Normal result of calculation - shock waves in fan stream without ripples near shock waves

paduchev December 16, 2012 12:56

No one knows)

Far December 16, 2012 14:05

I checked your mesh and it looks fine and every thing else looks ok also. Can you send the files?

paduchev December 16, 2012 22:13

Quote:

Originally Posted by Far (Post 397798)
I checked your mesh and it looks fine and every thing else looks ok also. Can you send the files?

Where can I send you files?

paduchev December 17, 2012 23:54

Quote:

Originally Posted by Far (Post 397798)
I checked your mesh and it looks fine and every thing else looks ok also. Can you send the files?

I have send you an email with result files


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