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May 18, 2014, 12:55 |
axial velocity definition
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#1 |
Senior Member
Ali reza
Join Date: Mar 2014
Posts: 110
Rep Power: 12 |
hi everyone
I have a question about axial velocity in fluent specially in 3D curved pipes. It is an elbow which the velocity inlet is in X direction and I have got contour in X direction and it shows velocity correctly but in the same section I have got an axial velocity and it shows wrong contour and quantities I can't understand axial velocity and I don't know is it trustful or not? |
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May 19, 2014, 07:46 |
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#2 |
Senior Member
A-A Azarafza
Join Date: Jan 2013
Posts: 226
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Hi,
It seems that you didn't define the axial direction correctly in your geometry modeler. I think, you should redefine the coordinate.
__________________
Regard yours |
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May 19, 2014, 15:04 |
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#3 |
Senior Member
Behrooz Jamshidi
Join Date: Apr 2013
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For axisymmetric problems, in which the rotation axis must be the x axis, the x direction is the axial direction and the y direction is the radial direction. (If you model axisymmetric swirl, the swirl direction is the tangential direction.)
Axial velocity means the velocity in x direction in axisymmetric problems. So when your solver is not axisymmetric, axial velocity is meaningless (but sometimes has meaning!). Get your z-velocity contour. Is it the same as your axial velocity contour? |
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May 19, 2014, 15:33 |
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#4 |
Senior Member
Ali reza
Join Date: Mar 2014
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thanks for support the velocity contour in z direction gives me just zero and I think at inlet I don't have any vector in z direction,
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May 21, 2014, 19:10 |
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#5 | |
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Sean Delfel
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Quote:
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May 22, 2014, 14:00 |
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#6 |
Senior Member
Ali reza
Join Date: Mar 2014
Posts: 110
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thanks for your support that's right but I don't know how to do that moreover the geometry was made by some pictures and I don't know all of angels and dimensions (it is 3d pipe that bends are not in the same plane) so finding axial velocity in each part by calculating the angels is some how needs great deal of effort.
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December 16, 2016, 15:15 |
Axial and crossflow velocity!!!!!!
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#7 | |
New Member
Ranjith Kumar J
Join Date: Dec 2016
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Quote:
Which i later figured out that when you change x from 0 to 1 and change z from1 to 0 in cellzoneconditions tab would solve that problem!!!!! But now the problem is to find Crossflow velocity(perpendicular to axial velocity).Now i dont know whether crossflow velocity is the same as radial velocity or tangential velocity or neither of them.Please explain what the respective velocities mean actually? I also need to plot diiferent vector plots of crossflow velociitres at different sections? PLEASE HELP!!!!!!!!!! |
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December 18, 2016, 11:38 |
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#8 |
New Member
Ranjith Kumar J
Join Date: Dec 2016
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CAN SOMEONE PLEASE HELP ME???????????
DESPERATELY NEED AN ANSWER.... |
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January 28, 2017, 07:17 |
radial_velocity
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#9 | |
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SAIF MASOOD
Join Date: Sep 2016
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Quote:
fluentp1-1-02000.jpg t.jpg Last edited by saifmasood; January 28, 2017 at 07:18. Reason: forget |
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April 30, 2019, 22:01 |
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#10 | |
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Ahmed
Join Date: Sep 2018
Location: Daejeon
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Quote:
You said that for axis symmetric problems, the rotation axis must be x-axis. Why is that? In my case, I am doing a simulation in Fluent with an axis symmetric rotating model with the axis of rotation in the y-direction. So, does that mean when I will go to plot velocity vectors (u, v, w) in Post processing, radial, axial and tangential velocity coressponds to u, v, and w respectively? For example, u=radial, v=axial and w=tangential. Or u and v become interchange? |
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April 30, 2019, 22:57 |
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#11 |
Senior Member
Behrooz Jamshidi
Join Date: Apr 2013
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Hi,
The reason is that in documentation it has mentioned that axis boundary must be in x direction and also must not be in negative Y values. So you cant even start a simulation with axis boundary in Y direction. You should rotate your mesh by 90 degrees and do your simulation. |
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May 1, 2019, 05:56 |
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#12 | |
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Ahmed
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May 1, 2019, 11:27 |
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#13 | |
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Lucky
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Quote:
The axis boundary condition must be on the y=0 line. It's in the Fluent manual. The axial velocity is the velocity vector in a different basis. You can have the "axis" of this coordinate system be in any direction. You need not use an axis boundary condition when you want to reference your velocity as axial/radial/tangential system. You also need not use axial/radial/tangential system when you are using an axis boundary condition. You can use an axis boundary condition and stick to cartesian coordinates. |
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