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Selecting Edges and Displacing Geometry. Also, Equations to Generate Geometry.
Posted 20 juil. 2014, 17:52 UTC−4 Fluid & Heat, Geometry Version 4.4 1 Reply
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Hello,
I am new to COMSOL, only have a 28 day free trial, and I need to model fluid flow.
This question is really two part.
One, I would like to build a nozzle that has two different diameters but with a closed surface. I believe the simplest method would be "cone" geometry with diameter specified instead of angle. I need to negatively displace the second smaller diameter vertically. As a visual, I provide an image with two disks, and a linear Bezier polygon connecting the two disks. In front of the first connected images is a cone. I need to negatively displace the smaller diameter of the cone to a position that would allow creation of the geometry to the left but with a closed surface provided by the cone.
Next, I need to draw complex geometry within a section of a cylinder that will be attached to the smaller diameter of the geometrically manipulated cone. I have equations to describe the geometry from Mac Grapher in three dimensions. Is there a way to use similar equations to create geometry since I cannot import MAC grapher files to COMSOL?
Finally, is there a way to actually enclose the surface between two disks (see image) that would allow me to also create a closed surface model of my nozzle? I was going to use the Bezier method, but that seemed counter intuitive since a single line is drawn.
Thanks.
I am new to COMSOL, only have a 28 day free trial, and I need to model fluid flow.
This question is really two part.
One, I would like to build a nozzle that has two different diameters but with a closed surface. I believe the simplest method would be "cone" geometry with diameter specified instead of angle. I need to negatively displace the second smaller diameter vertically. As a visual, I provide an image with two disks, and a linear Bezier polygon connecting the two disks. In front of the first connected images is a cone. I need to negatively displace the smaller diameter of the cone to a position that would allow creation of the geometry to the left but with a closed surface provided by the cone.
Next, I need to draw complex geometry within a section of a cylinder that will be attached to the smaller diameter of the geometrically manipulated cone. I have equations to describe the geometry from Mac Grapher in three dimensions. Is there a way to use similar equations to create geometry since I cannot import MAC grapher files to COMSOL?
Finally, is there a way to actually enclose the surface between two disks (see image) that would allow me to also create a closed surface model of my nozzle? I was going to use the Bezier method, but that seemed counter intuitive since a single line is drawn.
Thanks.
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1 Reply Last Post 20 juil. 2014, 20:22 UTC−4
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Posted:
10 years ago
Hello,
If possible, there I would still like answers to my other questions. Especially because extrusion might not satisfy all needs of complex geometry creation.
Question Solved:
"One, I would like to build a nozzle that has two different diameters but with a closed surface."
PNG file attached below.
Method:
I actually solved one of my geometric needs by right clicking "Geometry," selecting a "Work Plane," and creating the nozzle exit "circle". My work plane automatically included my larger diameter section.
I right clicked "Work Plane" and selected "Extrude." Since my larger 3D cylinder (entrance to nozzle) was included in my work plane, I thought I could extrude the circle directly to the 3D cylinder by electing both. The Extrude box gave me errors and would not allow me to select the 3D cylinder. For this reason, I right clicked the cylinder in the "model builder" and disabled it.
I then selected "Extrude" in the model builder and my work plane with a circle appeared. I then simply changed the distance to give depth, changed the scaling to the desired entrance diameter size, which I derived from a ratio of large diameter:small diameter, and I built the selected.
Thankfully, this worked. I believe I can use a similar method to design the exit of the nozzle, which I will be attaching to the included png file (see attachment).
Comment:
I would still like to know about the ability to mathematically model. I did find parametric surfaces and could create a cylinder with parametric surfaces, but I am wondering if their is a simpler method. One that would be similar to Mac Grapher where non-parametric equations are entered. With that said, I realize the extreme value you parametric equations for drawing complex geometry.
If possible, there I would still like answers to my other questions. Especially because extrusion might not satisfy all needs of complex geometry creation.
Question Solved:
"One, I would like to build a nozzle that has two different diameters but with a closed surface."
PNG file attached below.
Method:
I actually solved one of my geometric needs by right clicking "Geometry," selecting a "Work Plane," and creating the nozzle exit "circle". My work plane automatically included my larger diameter section.
I right clicked "Work Plane" and selected "Extrude." Since my larger 3D cylinder (entrance to nozzle) was included in my work plane, I thought I could extrude the circle directly to the 3D cylinder by electing both. The Extrude box gave me errors and would not allow me to select the 3D cylinder. For this reason, I right clicked the cylinder in the "model builder" and disabled it.
I then selected "Extrude" in the model builder and my work plane with a circle appeared. I then simply changed the distance to give depth, changed the scaling to the desired entrance diameter size, which I derived from a ratio of large diameter:small diameter, and I built the selected.
Thankfully, this worked. I believe I can use a similar method to design the exit of the nozzle, which I will be attaching to the included png file (see attachment).
Comment:
I would still like to know about the ability to mathematically model. I did find parametric surfaces and could create a cylinder with parametric surfaces, but I am wondering if their is a simpler method. One that would be similar to Mac Grapher where non-parametric equations are entered. With that said, I realize the extreme value you parametric equations for drawing complex geometry.
Attachments: