## Calculate Swirl Strength

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 = […]

## 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 […]

## 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 […]

## 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 […]