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residual and initial state of thruster nozzle

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Old   October 4, 2009, 08:28
Default residual and initial state of thruster nozzle
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Syed Daniel Shukri
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good day

my name is daniel.. i'm a final year bachelor student..

i had some trouble on my Final Year Project... i'm trying to observed the effect of altering the divergence angle and the divergence length on the CD nozzle..

i'm using Spallart Allmaras as my turbulence flow solver.. but its plot on my residual always diverge to the value of 10K.. sometime d iteration stop due to flowing point..

any pointer or paper is highly apritiated

S.D
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Old   October 6, 2009, 17:16
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Aroon
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Which of the equations causes the divergence? How is the mesh quality?

If it is the turbulence equation that starts the divergence, try activating the Cell Quality Remedaition.
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Old   October 7, 2009, 03:38
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Syed Daniel Shukri
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Spalart Allamaras is the solver..

in the residual.. the only diverge line is Sa_nut
my meshing quality is 0.1% of its original size

i'll try several method to avoid failure such as:
  1. using the 1st order convection in the turbulence flow menu
  2. and lowering the relaxation factor of the Spalart Allamaras
could this be done.. and is it valid..

ur point of viiew and comment is greatly appritiated
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Old   October 7, 2009, 15:47
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Is the Cell quality remediation switched on in your Physics model? This often helps in solving divergence problems related to turbulence equations.
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Old   October 9, 2009, 05:02
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Turn the normalization option of the residuals off.
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