# Poiseuille’s Law Calculator, Formula, Calculation of Pressure Change

### Poiseuille’s Law Calculator:

With our Poiseuille’s law calculator, you can easily find the volumetric flow rate and resistance to flow of a fluid moving in a pipe.

Derived from the Darcy-Weisbach equation, this law describes the pressure drop caused by a fluid flowing through a pipe. How to calculate volumetric flow rate; And Flow resistance equation from Poiseuille’s law. Poiseuille’s law, also known as Hagen-Poiseuille law or Hagen-Poiseuille equation, describes the pressure drop of an incompressible Newtonian fluid in laminar flow traveling across a cylindrical tube of constant cross-section. The pressure change, according to Poiseuille’s law, is given by the expression:

### Poiseuille’s Law Equation:

poiseuille’s law equation is the pressure change Δp(pa) in pascal is equal to the eight and multiply the dynamic viscosity of the fluid μ(pa) in pascal and multiply the length of the pipe L(m) in meter and multiply the flow rate Q(m2/s) in meter per second and divided by the pi value 3.14 and multiply the radius of the pipe r4(m) in meter.Hence the poiseuille’s law equation can be written as

Δp(pa)=8*μ(pa)*L(m)*Q(m2/s)/π* r4(m)

Where

Δp=pressure change in pa or psi

μ =Dynamic viscosity of the fluid in pa *s

L=length of the pipe in m or ft

Q=flow rate in m3/s or ft3/s and

R=radius of the pipe in m or ft

### Example:1

Calculate the dynamic viscosity of the fluid 25 pa and length 15m and flow rate 10 m3/s and radius 4m .find the pressure value?

μ =25pa

L=15m

Q=10 m3/s

R=4m

Δp(pa)=8*μ(pa)*L(m)*Q(m2/s)/π* r4(m)

Δp(pa)=8*25*15*10/3.14*(4)4

=8*25*15*10/803.84

=30000/803.84

=37.3208 pa

### Example:2

Calculate the dynamic viscosity of the fluid 8 pa and length 0.5m and flow rate 12 m3/s and radius 0.3m .find the pressure value?

μ =8pa

L=0.5m

Q=12 m3/s

R=0.3m

Δp(pa)=8*μ(pa)*L(m)*Q(m2/s)/π* r4(m)

Δp(pa)=8*8*0.5*12/3.14*(0.3)4

=8*8*0.5*12/0.025

=384/0.025

=15360 pa