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Old   March 17, 2008, 01:01
Default accuracy of solution
  #1
wan
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Hi All,

Inside solver control, there are 3 option which is [high resolution/upwind/specific blend factor]. What are those setting for? each setting will represent what kind of condition?

thank you
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Old   March 17, 2008, 17:31
Default Re: accuracy of solution
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Glenn Horrocks
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Hi,

Read the documentation. It is all explained there.

Glenn Horrocks
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Old   March 20, 2008, 12:05
Default Re: accuracy of solution
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Rogerio Fernandes Brito
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We are almost done. The next icon of interest, , opens up the Solver Control window. Unlike other programs that have a ton of possible settings for solver controls, CFX is quite simple. The solver itself is quite robust so you don't have to worry about the multitude of options presented in other codes. Click on the Solver Control icon to open up the window shown below in Fig. 5. Let's begin with the Advection Scheme. It has three possible settings: High Resolution, Upwind and Specified Blend Factor. The upwind scheme is a simple and robust convective scheme but can be very diffusive. It can be used to start up difficult problems but in general should be avoided. The Specified Blend Factor allows the user to enter a value between 0 (upwind) and 1 (2nd Order), this will fix the order of the scheme. The High Resolution option will attempt to set the order of the scheme as high as possible automatically while keeping the solution bounded everywhere. The High Resolution scheme is what I would recommend for users. I will go into more details about the advection schemes in future articles but for the most part, stick to the High Resolution scheme. Under Convergence Control, use the Auto Timescale for Timescale Control and also leave the value of 100 for Max Iterations. Keep the Length Scale Option set to Conservative. Change the Residual Type from RMS to MAX and leave the Residual Target at 1.E-04. A residual value of 1.E-04 for the RMS setting is good for obtaining a faster solution and to get an idea of how the flow is developing.
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Old   March 20, 2008, 12:07
Default Re: accuracy of solution
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Rogerio Fernandes Brito
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Setting the value of 1.E-04 for the MAX value gives a tighter convergence and is pretty good for extracting quantitative results for most problems. Click Ok to accept the settings. The next icon, , is useful for saving information during the solution of a model. You can save as much or as little information as you want and you also have several options to control when you save the information. We will skip this icon for this example.

Link: http://www.padtinc.com/epubs/focus/2..._54.pdf#Page=1
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