Poiseulles law states that the flow rate in a long, straight tube with laminar flow is proportional to its length and viscosity and inversely proportional to the fourth power of its radius.

See also Proportionality Constant.

Blood volume per time measured in: cm³/s.
The sonographic detection of blood flow in vascular ultrasound is limited by factors such as tissue motion (clutter), attenuation properties of the intervening tissue, and slow or low-volume flow.

Different flow types in human body:

See also Antegrade, Bi-directional Flow, Velocity, Poiseulles Law, and Venous Ultrasound.

The flow rate describes the volume of fluid passing through a given vessel per time unit. The flow rate is measured in milliliters per second ml/sec or liters per minute l/min.

See also Poiseulles Law.