hai all, I'm now doing a research about castor oil. i've a got a few a confusing problems.. 1. to flow castor oil in a 12 mm acrylic pipe i use a reservoir 1 metres from the outlet. Because castor oil is very thick (dyn visc. = 0.5 Pa-m), the velocity of the flow is very low just about 0.02 m/s, therefore the reynolds number i got is very small just about 0.35. do u guys think it's normal? coz' i've never found any case that has a reynolds number below 1 in an internal flow. 2. related to the first question, i got the friction factor for laminar flow using the eg f=64/Re, so i got about 140-150. do u guys think it's normal to have a friction factor > 1. that's my confusing problem, btw i dont want to use pump, because pump will break the oil's molecule. please help me here. =) Thanks.