The Darcy's Law (Physiology) calculator computes the blood flow (F) through a vessel based on a change in pressure (ΔP) and a resistance factor (R).
INSTRUCTIONS; Choose units and enter the following:
Flow Rate (FR): The calculator returns the Flow Rate in milliliters per minute. However this can be automatically converted into other volumetric flow units via the pull-down menu.
Heart / Blood Calculators:
Darcy’s Law was created to describe the flow of a fluid through a porous medium, specifically the flow of water through sand. The law has been significantly simplified for this application to Physiology here. See Darcy's Law (Engineering) for the more explicit version of this equation as typically applied to hydrogeology and engineering applications.
In the physiology application, Darcy’s Law has been interpreted as defining blood flow against resistance, where the peripheral resistance of the circulatory system to blood flow is analogous to the resistance of a medium like sand to the flow of water. The two inputs to this equation are:
Darcy's Law returns the cardiac output in terms of Liters per minute.
The Darcy's Law formula was derived from experimental data by Henry Darcy has the following form:
`Q = (-k*A (P_b - P_a)) / (mu * L)`, where
As you can see in contrast, the physiology version of "Darcy's Law" is somewhat simplified:
Cardiac Output = (Mean Arterial Pressure) / (Total Peripheral Resistance)