Calculating Average Normal Velocity to Iso-Surface

Problem: How do I calculate the average normal fluid velocity (or any vector variable) going through an iso-surface? Details: Or stated another way, “I am trying to use a vector dot product with unit normal integration to get the average normal velocity through an extracted iso-surface.”  This question originally relates to this scenario, but it can be used for calculating the average flux though a surface for various cases. Solution: […]

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Creating Streamtraces on a No-slip Boundary Surface with Multiple Surrounding Volume Zones

Problem: How do I create streamtraces on a no-slip boundary surface with multiple surrounding volume zones? In more detail: In the User’s Manual in the section titled “Surface Streamtraces on No-slip Boundaries”, it describes how to create these surface streamtraces in the context of an ASCII file with one parent (volume) zone. However, if other data file types are used or multiple parent zones, these instructions do not apply. Solution: […]

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Use of $!BASICSIZE to customize the size selections in Tecplot 360

Problem: The default sizes and line thicknesses are too varied and some are too large. Is there a way to customize the size selections? Solution: Using $!BASICSIZE from the configuration file, users can customize the default sizes in the user interface. For example, these commands will update the Line Thickness options and the Symbol Sizes: $!BASICSIZE LINETHICKNESSES { MEDIUM = 0.2 LARGE = 0.3 HUGE = 0.4 } SYMBOLSIZES { […]

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Calculate Lambda-2 Criterion

Problem: How do I calculate the Lambda-2 criterion? Solution: Use a Tecplot Macro to automate the calculation. Make sure Tecplot is aware of the variables representing your velocity field (Analyze->Field Variables menu).   The commands are as follow: Calculate the tensor of velocity gradients. This command can be obtained by recording the Analyze->Calculate Variables…->Velocity Gradient (tensor) action in Tecplot’s graphical user interface (GUI). $!EXTENDEDCOMMAND COMMANDPROCESSORID = ‘CFDAnalyzer4’ COMMAND = ‘Calculate […]

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Animation Export Size and Format Limitations

Problem: Windows Media Player (WMP) and PowerPoint cannot handle large .mp4 export files (image widths greater than 3000 pixels). Details: MP4 video animation export in Tecplot 360 (as of 2018.2.1) will display properly on Linux (using VLC), MacOS (QuickTime Player), and Windows (Windows Media Player, PowerPoint, and Web Viewer) with one exception: Windows Media Player and PowerPoint cannot handle MP4 image widths greater than 3000 pixels.   Solution: Exporting large WMV […]

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Invalid Connectivity Error Message when Slicing

Problem: I receive the following error when trying to create slices in my data: “Invalid Connectivity found when slicing cell ### from source zone #…” Solution: With the new option of Polygonal Slice mesh, which is meant to preserve the original mesh structure, invalid meshes create a bad cell in a slice. This is why the error is appearing. In many cases, the slices can be generated when switching to […]

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Precise Probe to Create Time Series Plot

Problem: How do I Probe to Create Time Series Plot at a given set of coordinates? Solution: Use Tecplot’s macro language to precisely define the point to probe. The commands are as follow: Prompt for the (X, Y, Z) coordinates of the point to probe: $!PROMPTFORTEXTSTRING |xPosition| INSTRUCTIONS = “Enter X position of the probe.” Or define them directly in the macro: $!VARSET |xPosition|= 0.1 Pass these coordinates to the […]

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Use FFmpeg to create videos from PNGs

Problem: I want to create a movie file from a series of images that I export from Tecplot. Solution:  Tecplot 360 2018 R2.1 introduced the ability to export animations to a series of images. FFmpeg, which is bundled with Tecplot 360, has commands to convert a set of images into a video format. Here is an example command: ffmpeg.exe -framerate 40 -i image%9d.png -s:v 1024×910 -c:v libx264 -profile:v high -crf […]

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Extract Vortex Cores over time

Problem: How do I extract vortex cores over time? Solution: Use a Tecplot Macro to loop over time and extract the vortex cores at each time step. Make sure Tecplot is aware of the variables representing your velocity field (Analyze->Field Variables menu).   The commands are as follow: Retrieve the number of time steps $!EXTENDEDCOMMAND COMMANDPROCESSORID=’extend time mcr’ COMMAND=’QUERY.NUMTIMESTEPS NUMTIMESTEPS’ Loop over time $!LOOP |NUMTIMESTEPS| $!EXTENDEDCOMMAND COMMANDPROCESSORID=’extend time mcr’ COMMAND=’SET.CURTIMESTEP […]

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Vortex Core Extraction Method

Problem: How is the Vortex Core calculated in Tecplot 360? Solution: The exact Vortex Core extraction method is defined in an AIAA paper called “Identification of Swirling Flow in 3-D Vector Fields” by David Sujudi and Robert Haimes of the Massachusettes Institute of Technology. Abstract An algorithm for identifying the center of swirling flow in 3-D discretized vector fields has been developed. The algorithm is based on critical point theory and […]

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