Viscous shear, average flow, and relaxation time close through refs. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Reuse the same height as the viscous gap
The audit checks that the viscous gap is the same 4 m height used by the shear strain source.
8/4=2
Join flow and time-scale sources
Flow rate 12 cubic metres per second and relaxation time 2 s are separate checked refs.