# BME 590 - Homework 2

Due: Aug 31, 2017

Answer the following questions after reading “Biotechnology at Low Reynolds Number” by Brody et al.

1. In words, what does the left hand side of eq. 1 describe?

2. Plot the flow profile, as a function of radius, for water flowing at room temp through a capillary tube with 100 $$\mu$$m inner diameter. Assume a pressure drop of 10 kPa and that the water is at room temperature. Write down any other assumptions that you make.

3. You want to mix two solutions over a length scale of 10 $$\mu$$m. You can stir with a velocity of up to $$10^2$$ $$\mu$$m/sec, or you can just let diffusion take its course. Which option yields a faster mixing time? Why?

4. Calculate the pressure generated by a meniscus in a capillary tube with diameter 50 $$\mu$$m. Assume $$cos\Theta =1$$.