what is meant by high resolution scheme in cfx

Mainly 2 types of schemes 1)UPWIND 2)High resolution your given upwind thenumber of iteration will take slowly one by one in case High resolution:very fast iterations will take time consuming.

Hi,

You will find an explanation in section 4.2.2 of this article: Numerical and Experimental Studies of the Flow Field in a Cyclone Dryer

Regards,

Greg

Step 6: Solver Control Setting 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.

Setting the value of 1.E-04 for the MAX value gives a tighter convergence and is pretty good for extracting quantitative results 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.

Source: December 15, 2006 - The Focus - Issue 54

[manpreet]

Hello Everyone,
I am Manpreet. I need help fpr my project that is Fluid flow analysis through passage of NASA Rotor 37. I am working with CFX. I am not familiar with certain terms such as Advection scheme, Turbulence numeric , RMS and Timescale control. What are physical significance of all these terms and their effect on solution. In my case, using:
Advection scheme: High resolution
Turbulence numeric: First order
RMS: 1E-4
Time scale : 1E-5. But I do not know why these specific values?
In addition , What does it mean by solution being bounded and overshoot , undershoot?
Please help me . I need to submit my results by next week.
I really appreciate.
Thanks
manpreet_singh_er@yahoo.co.in

[ghorrocks]

These are very basic CFD concepts. Any introductory CFD text will explain them to you - so time to visit the library.

And before you ask, no I will not type definitions of all that stuff in the forum. It is easily found in any CFD textbook.