Fig. 7.

Quantification of the minimum measurable flow velocity $|v_{\min }|$ for 10-μm-diameter microspheres. (a) Measured flow velocities for three different distances at slow preset flow velocity range $|v|=0.06–0.46\mathrm{mm}/\mathrm{s}$ for a fixed time $t_{\text{total}}=100\mathrm{ms}$. (b) Measured flow velocities using three different $t_{\text{total}}$ at a fixed distance $L=5\mu \text{m}$.