compute_derived_fields Subroutine

public subroutine compute_derived_fields(solver, output_vorticity, output_qcriterion)

Compute derived fields from the velocity gradient tensor.

All 9 components of the velocity gradient tensor are computed once, then used to evaluate whichever quantities are enabled (vorticity magnitude, Q-criterion). Vorticity magnitude: $|\boldsymbol{\omega}| = \sqrt{(\partial w/\partial y - \partial v/\partial z)^2 + (\partial u/\partial z - \partial w/\partial x)^2 + (\partial v/\partial x - \partial u/\partial y)^2}$ Q-criterion (second invariant of the velocity-gradient tensor): $Q = \frac{1}{2}(u_x+v_y+w_z)^2 - \frac{1}{2}(u_{x}^2 + v_{y}^2 + w_{z}^2) - u_{y}v_{x} - u_{z}w_{x} - v_{z}w_{y}$

Arguments