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-   -   Wave elevation vs tank length (https://www.cfd-online.com/Forums/cfx/125538-wave-elevation-vs-tank-length.html)

lingyo October 27, 2013 22:15

Wave elevation vs tank length
 
Hello.
I´m simulating waves.I know how to plot in a chart the wave elevation vs time.
but I can't figure out how to plot wave elevation(or wave profile) vs tank length,can anyone help?? thanks

ghorrocks October 28, 2013 04:13

Well, what actually is wave profile versus tank length anyway? You are trying to reduce a 3D field to a 1D line, so you have to do the reduction somehow - maybe sampling along a line, averaging across a profile or some other method. So let us know how you plan to do this reduction in dimensions and we will see if we can help you.

And please do not duplicate post again in future. I have deleted the duplicate post.

lingyo October 28, 2013 07:44

3 Attachment(s)
Thank you very much , Glenn.
My simulation is shown in fig.1
I did a plane and use expression"areaInt(WATER.Volume Fraction)@Plane/20[m]" to plot fig.2,and the chart is composed by wave profile vs time.
my question is,is it possible to plot the chart composed by wave profile vs tank length(x)like fig.3 ??
I can't chose "x" in X values when the xy-transient is selected.
If select xy,I can chose "x" in X values but I don't know how to express the Y values :confused:

ghorrocks October 28, 2013 16:46

You can do this in CFD-Post using a session file to generate the data points and export them so you can plot them elsewhere.

Also, as your waves are just about 2D then you can take the side plane and draw a VF=0.5 contour and that is your wave profile. You might be able to plot that line as an XY plot; or you can export the line and plot it in another package like matlab, excel or whatever you like.

kailashnadhrokkam August 6, 2018 12:12

Wave profile
 
Quote:

Originally Posted by lingyo (Post 459405)
Thank you very much , Glenn.
My simulation is shown in fig.1
I did a plane and use expression"areaInt(WATER.Volume Fraction)@Plane/20[m]" to plot fig.2,and the chart is composed by wave profile vs time.
my question is,is it possible to plot the chart composed by wave profile vs tank length(x)like fig.3 ??
I can't chose "x" in X values when the xy-transient is selected.
If select xy,I can chose "x" in X values but I don't know how to express the Y values :confused:



create an iso surface and select volume fraction of water phase as your variable

Ivan Ahda October 21, 2018 04:55

Quote:

Originally Posted by ghorrocks (Post 459509)
You can do this in CFD-Post using a session file to generate the data points and export them so you can plot them elsewhere.

Also, as your waves are just about 2D then you can take the side plane and draw a VF=0.5 contour and that is your wave profile. You might be able to plot that line as an XY plot; or you can export the line and plot it in another package like matlab, excel or whatever you like.

Could you tell me please how to plot it in 2D, wave elevation vs flowtime, step by step, i need it for my project, thanks

ghorrocks October 21, 2018 05:30

If you want a wave history at a point one way of doing it is to define a monitor point with the CEL function max(water.volume fraction*y). This assumes your liquid phase is called water and positive y is upwards.

Ivan Ahda October 21, 2018 05:41

1 Attachment(s)
Quote:

Originally Posted by ghorrocks (Post 711724)
If you want a wave history at a point one way of doing it is to define a monitor point with the CEL function max(water.volume fraction*y). This assumes your liquid phase is called water and positive y is upwards.

How to do that? my simulation is 2D
i want to plot my simulation in CFD post

ghorrocks October 21, 2018 05:53

On second thoughts, I don't think my function on the last post will work :(

Where in your simulation do you want the wave height?

Ivan Ahda October 21, 2018 05:57

1 Attachment(s)
Quote:

Originally Posted by ghorrocks (Post 711729)
On second thoughts, I don't think my function on the last post will work :(

Where in your simulation do you want the wave height?

i want to plot just like this

ghorrocks October 21, 2018 16:47

Sure, but at what point do you want to generate the height data from? The inlet or outlet boundaries are the easiest places.

Ivan Ahda October 22, 2018 11:25

Quote:

Originally Posted by lingyo (Post 459405)
Thank you very much , Glenn.
My simulation is shown in fig.1
I did a plane and use expression"areaInt(WATER.Volume Fraction)@Plane/20[m]" to plot fig.2,and the chart is composed by wave profile vs time.
my question is,is it possible to plot the chart composed by wave profile vs tank length(x)like fig.3 ??
I can't chose "x" in X values when the xy-transient is selected.
If select xy,I can chose "x" in X values but I don't know how to express the Y values :confused:

could you tell me please how to plot like that, step by step, thanks
elevation vs flowtime

Ivan Ahda October 22, 2018 11:29

Quote:

Originally Posted by ghorrocks (Post 711784)
Sure, but at what point do you want to generate the height data from? The inlet or outlet boundaries are the easiest places.

from the inlet, could you help me to do that step by step?
my simulation is in 2D domain

ghorrocks October 23, 2018 20:29

I am not going to write a step by step guide. I don't have the time.

If you do a CEL expression for the area integral over the inlet boundary of the water volume fraction it will give you the area of the inlet under the water level. If the thickness of the inlet is known you then have the height.

Ivan Ahda November 6, 2018 02:51

1 Attachment(s)
Quote:

Originally Posted by ghorrocks (Post 712261)
I am not going to write a step by step guide. I don't have the time.

If you do a CEL expression for the area integral over the inlet boundary of the water volume fraction it will give you the area of the inlet under the water level. If the thickness of the inlet is known you then have the height.

i dont have time too to understand your explanation so i search other explanation

Kathe November 23, 2023 15:50

Quote:

Originally Posted by Ivan Ahda (Post 711727)
How to do that? my simulation is 2D
i want to plot my simulation in CFD post

Hi Ivan, I have problems with plotting the free surfaces as you show in your first image. Can you tell me how to do it, please?

Kathe November 23, 2023 15:51

Quote:

Originally Posted by lingyo (Post 459405)
Thank you very much , Glenn.
My simulation is shown in fig.1
I did a plane and use expression"areaInt(WATER.Volume Fraction)@Plane/20[m]" to plot fig.2,and the chart is composed by wave profile vs time.
my question is,is it possible to plot the chart composed by wave profile vs tank length(x)like fig.3 ??
I can't chose "x" in X values when the xy-transient is selected.
If select xy,I can chose "x" in X values but I don't know how to express the Y values :confused:

Hi, I have problems with contouring the wave elevation as you show in your first image. Can you tell me how to do it, please?

ghorrocks November 23, 2023 18:54

The images are just a iso-surface of volume fraction (of vf=0.5).


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