Calculate Swirl Strength

Macro, Tecplot 360, Vortices June 7, 2019

Problem: How do I calculate the Swirling Strength criterion (Lambda-Ci)? 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 user interface (UI). $!EXTENDEDCOMMAND COMMANDPROCESSORID = ‘CFDAnalyzer4’ COMMAND = […]

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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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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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How to calculate the circulation around a vortex core.

Calculation, Tecplot 360, Vortices January 28, 2010

Problem: I extracted a vortex core using the Tecplot CFD Analyzer, and now I want to calculate the circulation around the core. How can I do this? Solution: If you can define a closed path in your data over which to integrate, you can calculate circulation using the Integrate dialog. Open the dialog by choosing “Perform Integration” from the Analyze menu. In the Integrate dialog that appears, for Type of […]

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