Reynolds+number

=Reynolds Number=

toc Read here about a general relationship, expressed as a quantitative but unitless variable, that can serve as a guide to comprehending behavior in different scales.

=Overview= Reynolds number is the ratio of inertial forces to viscous forces. It is particularly important in pipe flows and aircraft model studies. The Reynolds number also characterizes different flow regimes (laminar, turbulent, and the transition between the two) through a critical value. For example, for the case of flow of fluids in a pipe, a fluid is considered turbulent if R is greater than 2,000. Otherwise, it is taken to be laminar. A turbulent flow is characterized by random movement of fluid particles.

Reynolds number is very significant to the behavior of life, since life is organized around liquid water.

=Comparing to Human Scale= Bonner wrote: To imagine living in a realm with low Reynolds number, "imagine swimming in thick molasses in which one was not allowed to move one’s arms or legs faster than the hands of a clock."

Keep this in mind when viewing animations of cellular life, such as those by XVIVO.