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sotirios May 16, 2013 04:27

Getting streamlines between two planes in post-CFD
 
2 Attachment(s)
Hi all,

My name is Sotirios! I'm new to these forums and am very keen to be apart of this community.

I have a question regarding using ANSYS's post-CFD software package:

Background info
I have two fluid inlets (blue and red arrows) that culminate in a T-junction for a cylindrical pipe geometry (see attachment). After the two pipes have become one, I have a two planes, A & B, that make a cross section of the pipe such that their surface normal is in the same direction as the flow, which is "down the pipe" (in the direction of the green arrow).

Attachment 21807

What I've previously been doing is starting some streamlines at the two inlets (red and blue arrows), and then exporting the streamline data to a .csv file in order to produce a cross section image of what it would the flow would look like if I were staring down the pipe (see other attachment)

Attachment 21811

In this .csv file are the coordinates of each streamline as it goes through the geometry and so it's given in the format (for example):

[x] [y] [z] [streamline number]
0.1 0.2 0.1 123
0.1 0.4 0.1 123
etc...

This can take a while and produce large files that get up to a 1gb if I use 10,000 streamlines per inlet which is not ideal if only because it wastes a bit of time.

What I'd like to find out
Does anyone know how to obtain streamlines that start from the plane at location "A" and stop at the plane at location "B"?

I hope that is sufficiently clear and that it's doable!

mjgraf May 16, 2013 09:34

assuming this is single phase.

if you are using simple XZ planes (y = constant) then you can use iso clip on each stream to bound between the two planes then export this. You get your points along the streamline between these two planes but lose the streamline numbers and just get a cloud of points.

One thing I have been wanting in CFDpost is to generate a point cloud using intersection of surfaces and streamlines. I can easily do this for simple cases of planes on a coordinate axis and then use max/min variable value. So if your A and B are y = constant, then use the iso clip as the part to create "Point" using maxVal Y and another using minYal Y then change to small balls and color as desired. No need to export streamline data to file and all visualization done within CFDpost.

If anyone has thoughts on intersecting streamlines with surfaces (any type) in CFDpost, I would be interesting in discussing.

If you are using two phases, look at the volume fraction on those planes to see distribution.


Quote:

Originally Posted by sotirios (Post 427930)
Hi all,

My name is Sotirios! I'm new to these forums and am very keen to be apart of this community.

I have a question regarding using ANSYS's post-CFD software package:

Background info
I have two fluid inlets (blue and red arrows) that culminate in a T-junction for a cylindrical pipe geometry (see attachment). After the two pipes have become one, I have a two planes, A & B, that make a cross section of the pipe such that their surface normal is in the same direction as the flow, which is "down the pipe" (in the direction of the green arrow).

Attachment 21807

What I've previously been doing is starting some streamlines at the two inlets (red and blue arrows), and then exporting the streamline data to a .csv file in order to produce a cross section image of what it would the flow would look like if I were staring down the pipe (see other attachment)

Attachment 21811

In this .csv file are the coordinates of each streamline as it goes through the geometry and so it's given in the format (for example):

[x] [y] [z] [streamline number]
0.1 0.2 0.1 123
0.1 0.4 0.1 123
etc...

This can take a while and produce large files that get up to a 1gb if I use 10,000 streamlines per inlet which is not ideal if only because it wastes a bit of time.

What I'd like to find out
Does anyone know how to obtain streamlines that start from the plane at location "A" and stop at the plane at location "B"?

I hope that is sufficiently clear and that it's doable!



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