public float flowVariation { get; set; }

Fluid flow can be defined to move in any direction with a specific magnitude and a random variation on that magnitude.

This property defines the random variation in addition to _flowMagnitude of the force to be applied in the direction defined by _flowAngle.

The flow forces are applied to the center of any submerged region of a Collider2D so it will not produce any torque (rotation) if the Collider2D is fully submerged (fully below the _surfaceLevel) but will produce torque if the Collider2D is partially submerged (overlapping the _surfaceLevel).

Additional Resources: _flowAngle, _flowMagnitude