Calculate Lambda-2 Criterion

Macro, Tecplot 360, Vortices March 21, 2019

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

Animation, Export, Image, Tecplot 360 March 11, 2019

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

Derived Objects, Error, Tecplot 360 March 7, 2019

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

Macro, Tecplot 360 February 28, 2019

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

Export, Image, Tecplot 360 February 27, 2019

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

Macro, Tecplot 360, Vortices February 27, 2019

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

Calculation, Tecplot 360, Vortices February 6, 2019

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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Multi-Threading and Parallel Processing

Performance, Tecplot 360 January 7, 2019

This article will list the different portions of Tecplot 360 that use Multi-Threading and Parallel Processing. Each portion of what is used can be found in the table below: What How CFDA Integration is performed concurrently. Geometry boundary generation is performed concurrently. The following calculated variables are calculated concurrently: Cross Flow Velocity, Density, Dynamic Pressure, Enthalpy, Entropy, Entropy Measure S1, Equivalent Potential Velocity Ratio, Internal Energy, Kinetic Energy, Mach Number, […]

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Time Strands and the Zone Style dialog

Animation, Layout, Tecplot 360 November 20, 2018

When working with transient datasets, Tecplot implements “Time Strands”. Time Strands are assigned to a group of zones which represent the same object. For simple transient datasets, sometimes only one Time Strand is used. Whereas more complex datasets will implement multiple Time Strands. For example, if you are plotting a jet, typically there will be one Time Strand per wing, one for the fuselage, and one for the tail. Time […]

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