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-   -   Gridgen- Connector redistribution function (https://www.cfd-online.com/Forums/pointwise/13712-gridgen-connector-redistribution-function.html)

 sea June 23, 2007 15:43

Gridgen- Connector redistribution function

Hi all, I have created a cubical computational domain with each side measuring 10 cm. I am now trying to create a square injection region (0.5 cm) on one face. To be specific, the grid density is 31x35x35 and say I wish to have the jet inflow region consisting of the grid points J21 to J25 and K21 to K25 on the I1 boundary.

Is there a way of specing that the distance between these grids measure 0.5 cm ? Can redistribution function be used to do this? How can I achieve grid refinement at the center of a connector? From all I tried I think grid refinement can only be done at the ends of a connector.

I tried to create the inflow region as one domain, but then on creating the remaining domains the grid distribution looks weird.

I would appreciate any suggestions. Sorry, I know the mail is bit long.I am new to Gridgen, please help.

Thank you. sea

 ztdep June 24, 2007 12:46

Re: Gridgen- Connector redistribution function

Hi friends:

I think it is not very difficult to do this since you know the lenght of the line, you can specifiy the number of gridpoints to obtain a 0.5 cm grid.

if the redistribution function can not do this job , i thind it is better to seperature the grid system into many blocks. Regards

 John Chawner June 30, 2007 13:29

Re: Gridgen- Connector redistribution function

Sea,

To cluster points on a connector's interior, you insert a breakpoint into the distribution. A breakpoint is to the distribution what a control point is to the shape. A breakpoint is a grid point on a connector's interior at which you can specify the spacing constraint on either side. Also, adding a breakpoint divides the connector into two subconnectors in which you can set the distribution function.

Another way to accomplish your goal is to create two domains with one specifically for the injection region. That might actually work better, because you'll be able to specify boundary conditions on each domain.

I hope this helps.

 Sea July 10, 2007 18:32

Re: Gridgen- Connector redistribution function

Thanks John, Could you please give a little more information, how can I create 2 domains? The injection region would be 1 domain but, then the face of the domain with the injection region will have several domains(a central square domain and atleast 4 other surrounding this domain). Wouldn't the grids get distorted then (since I need finer grids inthe injection region)? I am trying to keep the grids simple.

How can I introduce a break point at a specific distance and not a grid point on the connector?

Thanks again.

Sea

 John Chawner July 10, 2007 20:41

Re: Gridgen- Connector redistribution function

Sea,

If I understand your topology correctly, the only way to make 2 domains is one for the injector with an H topology and one around it with an O topology. Otherwise, you can make something like a tic-tac-toe board.

As for the break point, there has to be a grid point there. But once you place it, you can have a single connector with clustering on the interior.

 Sea July 11, 2007 15:56

Re: Gridgen- Connector redistribution function

Thanks John, I think right now sounds like the tic-tac-toe board sounds simple to do. Could you please tell me how the H and O topologies can be implemented in Gridgen? I would appreciate it if you could please point me to some illustrative tutorial.

Thank you very much. Sea

 John Chawner July 11, 2007 19:08

Re: Gridgen- Connector redistribution function

Sea,

I can't think of any of our existing tutorials that go into detail about how to create an O-H topology. This topo is a variation of what's sometimes known as a butterfly topology. Let me try to describe it in words.

Assume you have a square inside a circle. Draw 4 lines connecting the square's 4 corners to the outer circle. All 5 resulting grids are H grids. If you joined the outer 4 grids into one, it would have an O topology.

Hope this helps. If you're still having a problem, email your Customer ID and a picture of what you're trying to accomplish to support@pointwise.com.

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