surface planes in gambit
 

hi all

i have created a horizontal pipe and i now want to create surface planes inside the pipe..if anyone knows how can one create planes in gambit plz guide me how do i do...

thanks in advance Falak

Re: surface planes in gambit
 

If the planes are for post-processing, you create them in Fluent. If they're for dividing the domain, or as source terms for sizing functions, then there's a lot of ways you can create them in Gambit. You can start create vertices, then connect the vertices with edges, and create a plane from a wireframe. Or you can pick from the standard shapes (like a rectangle, circle, etc) in the Face commands and then move it to where you need it. Or you can start with an edge and extrude it along a vector, or along a curve.

In the face commands, look at the 4 buttons on the left of the command window (the top two are surface creation tools, the bottom two are manipulation tools... if you right-click on the icons there are more options that appear).

What exactly are you trying to do, and what are you planning on using the surfaces for?

Good luck, Jason

Re: surface planes in gambit
 

Do you want to create a face in preprocessing stage or a surface in postprocessing stage?

Re: surface planes in gambit
 

thanx for ur response.... iam using the planes in my geometry for post processing...actually iam working on two phase flow ie immiscible liquids in horizontal pipe..so i want to see the distribution of the two phases after simulation by creating surface planes....i tried creating them in fluent but whn i click display only the planes after simulation it does not give the circular shape but the irregular shape of the plane...hope u can imagine...

i doubt whether the plane created by me is correct ...if u knw hw to create circular planes along the length of the pine plz explain..

thanks again rashmi

Re: surface planes in gambit
 

hi i want to create a surface in post processing stage....i knw i can create in fluent but dont knw the procedure...

Re: surface planes in gambit
 

You say the planes are circular, so I'm guessing they're cross sectional planes, and since the pipe is horizontal, I'm assuming that's along the x-axis. So what you want is a plane in the y-z plane and spaced out every so often along the x-axis, correct?

I'm not entirely sure what you mean by "it does not give the circular shape but the irregular shape of the plane" but using my assumptions above, this is how I recommend creating the planes:

Go to Surface->Plane. I prefer "Point and Normal" under Options (instead of 3 points, you only need 1 point and a normal vector). Your point would be (x,0,0) where x is the location along the x axis you want your plane, and your normal would be (1,0,0) so that your plane is normal to the x-axis. Also, give the plane a name that makes sense like "x=1.0m" or something like that... otherwise you end up with plane-1, plane-2, plane-3, etc and you can easily lose track of what the planes are.

If this doesn't help, then create an image of what's happening and send it to jason_at_bae@yahoo.com. Actually, if you can send me a picture of what you were talking about when you said "it does not give the circular shape but the irregular shape of the plane" I'd appreciate that as well.

Hope this helps, and good luck, Jason

Re: surface planes in gambit
 

There's lots of options in Fluent. They're all under the Surfaces menu. Surface->Plane will create a planar surface using 3 points, a point and a normal vector, offset from a surface, or aligned with the view plane. Surface->Iso-Surface will create planes based on just about any iso-value (pressure, temp, velocity, grid location, turbulence values, etc...). I highly recommend playing around in there and learning what the different options do. Like in the Iso-Surface menu there's the "From Surface" selection box... what happens here is that it will create a curve where the iso-surface and the "from surface" intersect (instead of creating an entire surface).

Also, I noticed you had a post about creating points for monitoring data... You can create the point under Surface->Point, and then go to Solve->Monitors->Surface to set options for monitoring data at that point during the iteration process. You pick how many monitors you want, then you click the "define" button for each monitor and set the optoins of what you want to monitor and at what "surface" you created (where in this case "surface" includes all points, lines, rakes, planes, or surfaces created under the Surface menu or imported with the mesh).

You can create a surface (point, line, rake, plane, or surface) at almost any time(after initializing, during the iteration process, or after you reached your solution). You can also turn on, turn off, or modify monitors at any time.

It's really worth playing around with these optoins because they are very valuable for monitoring your solution and for post-processing your results.

Hope this helps, and good luck, Jason

Re: surface planes in gambit
 

Hi Jason,

Did you know how to create the streamline in post-processing? If you know, I will appreciate your sharing.

Lam

Re: surface planes in gambit
 

For 2D, you can simply plot contours of stream function (instead of pressure, temp, etc) and if you turn off the "filled" option you will get lines that represent the stream function. You can play around with how they look by changing the number of intervals and by turning of "Auto Range" and adjusting the maximum or minimum values.

In 3D it's still pretty easy, but takes more computer power.

Go to: Display->Pathlines

You pick where you want your pathlines to start by selecting a point, line, rake, plane, or surface under "Release from Surfaces". A lot of times I'll go and create a rake upstream (a rake is a line with release points spaced out equally along the length, instead of a normal line where the points along it are wherever the line intersects a face) and then I'll display pathlines and release them from the rake I just created. If you have a big mesh this is going to take a while while it processes the pathlines. If you display the pathlines and they are too short (they don't exit the domain, or at least extend as far as you'd like) then you can increase the number of steps. In the users guide, Chapter 29.1.4 has a lot more info on the Pathlines, but the info I gave should be enough to get you started.

Hope this helps, and good luck, Jason

Re: surface planes in gambit
 

thank u very much for detailed explaination

iso surface
 

How to create rectangle iso-surface in fluent?
plz help

You can do it in cfd post by combining iso surface and iso clip.

Daniele