, is computed for each cell as:
The Field Covariance is the statistical covariance of two field function values over time, computed for each cell or boundary face in the selected parts. Two separate properties exist for the Field Covariance monitor's field function selection: FieldFunction 1 and FieldFunction 2.
The covariance is based on data samples collected at a user-specified time-step frequency for each cell of the parts being monitored. The sample covariance, , is computed for each cell as:
where:
is the Field Function 1 value at collection step 
.
is the Field Function 2 value at collection step 
.
is the number of time steps for which data has been collected.