Useful Postprocessing Techniques Using the Graph Marker Tool

In this month’s Tips and Tricks video, I am going to demonstrate some useful postprocessing techniques using the “Marker” and “Graph Marker” subnodes. A very simple problem of acoustic scattering is used as an example, however, demonstrated postprocessing techniques can be used for any other physics.

Click below to watch as I walk you through the process. To help you follow along, we have included the video transcription below.

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Useful Postprocessing Techniques Using the Graph Marker Tool Transcription

Welcome to Tips and Tricks video. In this video we will demonstrate how to use “Marker” feature for some useful postprocessing techniques.

For demonstration purposes, we will use very simple problem of acoustic scattering. Here we have water domain and surrounding air. We are using Pressure Acoustic physics interface to solve a sound scattering problem.

We use ‘Background Pressure Field’ to specify incident pressure field. Incident pressure is ‘Plane Wave’ traveling upward. ‘Plane Wave Radiation’ boundary conditions are used to model open boundaries. Let’s look at the results. Here we have surface plot for acoustic pressure. Assume we want to know where peak pressure is located. To find this out add ‘Marker’ subnode. This will display location and peak pressures. Currently, you have six digits for the pressure magnitude. You can control this by editing ‘Display precision field’ and also you can check ‘Include unit’ box to display units for the pressure. To display X and Y coordinates of the peak pressure locations, check box ‘Prepend the position’. If we are interested in the maximum value only then we can use ‘Display’ selection list to select appropriate option. Now only maximum peak pressure is displayed.

‘Marker’ tool can also be used for the XY plot. To demonstrate this, we will use ‘Cut Line’ in the data set to create line intersecting our model to the middle. Then we use this Cut Line to plot pressure as a function of the X coordinate. Now we’re ready to demonstrate the ‘Marker’ tool for the XY plot. Right click ‘Line Graph’ and add marker ‘Graph Marker’ subnode. By default, this will display minimum and maximum value of the pressure. If you want to display all peaks, then we go to the ‘Display’ section and change ‘Scope’ from ‘Global’ to ‘Local’. Click ‘Plot’ and now all local peaks are displayed. You can use ‘Display precision’ edit field to control how many digits we want to display. Now only two digits are used to display the pressure. Let’s change the ‘Display Scope’ back to ‘Global’. To display location of the pressure peaks, check box “Show X coordinate.” To display units of the pressure check box ‘Include unit.’ Now the location of the pressure peaks and units of the pressure are displayed.

So far, we have been exploring ‘Default’ display mode which is ‘Min and max’ mode. Let’s change Display mode to ‘Width’. This mode can be used to measure width of the peaks in the XY plot. A typical application would be to display bandwidth for S parameter analysis. For example, let’s measure peak width at Y equal to -.5. To do that we set ‘Cut off’ value to -.5, click ‘Plot’ and we see that the bandwidth at this level is .16 meters. Let’s change ‘Cut off’ value to -1, click ‘Plot’ and now we measure bandwidth of all three local peaks.

There is yet another display mode which is ‘Line intersection’ mode. In this mode we have several options for the ‘Line type’: Vertical, Horizontal, Identity line, and General. You can use this display mode to add markers at the intersections of the curve and straight line. Let’s start with Vertical line. We define X coordinate say .2 and click ‘Plot’ to see pressure value at the intersection. To see the line, check box ‘Show lines’. Also, you can specify several lines at the same time. Let’s type .2 and -.2 then click ‘Plot’ to see multiple intersections. To mark intersections with horizontal line, switch to ‘Line type’ Horizontal. Then type Y coordinates say -.5, click ‘Plot’ to see intersections of the straight line horizontal with our pressure curve. Identity line gives intersections with straight line with equation Y equal to X, which is actually 45-degree line. To specify straight line by defining 3 coefficient A, B, and C. Let’s type A equal to two, B equal to 1, and C equal to .5, then click ‘Plot’ and this will give us 4 intersections of the straight line with our curve.

That’s all for now. Hope this has been helpful and thank you.