What is Laminar Flow? Laminar flow is a type of flow pattern of a fluid in which all the particles are flowing in parallel lines, opposed to turbulent flow, where the particles flow in random and chaotic directions. A flow is either turbulent, laminar, or somewhere in between. This is measured by the Reynolds number which is a ratio between velocity (the speed of the flow) and viscosity (how thick or thin the fluid is). The more viscous, or thick, the fluid is the faster it can flow without goin