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Visualizing Turbulent Flow Features Using Surfaces

How can I visualize turbulence and flow features using surfaces?
The Q criterion, introduced by Hunt et al. in 1988, is commonly used to identify regions of recirculation in flow fields.

As of FieldView version 17, Q-criterion is a built-in function available on the Function Calculator, increasing peformance as compared to using this function via feature_detection_formulas.frm available with previous versions of FieldView, explained below.

Q-criterion provided with earlier versions of FieldView: We provide this (and other variations on the Q criterion formulas) with the Formula Restart feature_detection_formulas.frm in the FieldView installation directory fvx_and_restarts.

Please refer to the FVReference_Manual.pdf Chapter 8 Advanced Numerical Functions section Feature Detection Formulas for an illustration, explanation and usage examples of this feature.

NOTE: Users must make sure that this formula file restart (.frm) has the scalar functions for Ux, Uy and Uz set to the corresponding scalar function name for the user’s solver. For instance, if reading a plot3d or OVERFLOW dataset, then Ux would be “u-velocity [PLOT3D]“. Otherwise the function would not be computed. Formulas provided with restarts like this become available by reading them with File.. Open Restart.. Formula on the main menu.