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How does the dissipation of a supersonic underexpanded jet depend on grid fineness

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Old   July 2, 2015, 00:39
Default How does the dissipation of a supersonic underexpanded jet depend on grid fineness
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gautham narayan
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I have recently tried to simulate the acceleration due to friction in the a micro channel flow. I find that even though the peak mach numbers match up with previous experiments, the jet breakdown occurs much sooner than expected.

This gives birth to the question on whether the making the grid finer near the nozzle exit and continuing till the boundary would help carry on the jet further, how influential would this be.

In my understanding, having a high aspect ratio cell would lead to more dissipation, can anyone help me in understanding how much effect would the cell aspect ratio would have on the jet breakdown.



thanks,
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Old   July 2, 2015, 07:50
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Filippo Maria Denaro
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Quote:
Originally Posted by gauthamnarayan View Post
I have recently tried to simulate the acceleration due to friction in the a micro channel flow. I find that even though the peak mach numbers match up with previous experiments, the jet breakdown occurs much sooner than expected.

This gives birth to the question on whether the making the grid finer near the nozzle exit and continuing till the boundary would help carry on the jet further, how influential would this be.

In my understanding, having a high aspect ratio cell would lead to more dissipation, can anyone help me in understanding how much effect would the cell aspect ratio would have on the jet breakdown.



thanks,

In any simulation, the grid refinement assessment is a good job ;-)

however, many other issues can affect the solution, such as BC.s
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