Calculating Pressure Difference in Blood Flow Using Bernoulli's Equation

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SUMMARY

The discussion focuses on calculating the pressure difference in blood flow using Bernoulli's Equation. An artery with a radius of 1 mm and blood flow speed of 0.8 m/s transitions into three smaller veins with a radius of 0.5 mm, where blood speed increases to 1.07 m/s. The pressure difference between the artery and the smaller veins is calculated using the equation P1 + d*g*y1 + 1/2 *d*v1^2 = P2 + d*g*y2 + 1/2 *d*v2^2, resulting in a pressure difference of 3341 pascals. The discussion highlights the limitations of using Bernoulli's Equation for blood flow due to the fluid's viscosity and suggests that Hagen-Poiseuille flow may be a more appropriate model.

PREREQUISITES
  • Understanding of Bernoulli's Equation
  • Knowledge of fluid dynamics principles
  • Familiarity with Hagen-Poiseuille flow
  • Basic concepts of blood viscosity and flow rates
NEXT STEPS
  • Research the application of Hagen-Poiseuille flow in biological systems
  • Study the limitations of Bernoulli's Equation in viscous fluids
  • Explore the relationship between blood viscosity and flow rate
  • Learn about the effects of arterial radius on blood pressure and flow dynamics
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Students and professionals in biomedical engineering, fluid dynamics researchers, and healthcare practitioners interested in cardiovascular fluid mechanics.

GemmaN
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"An artery of radius 1 mm leaves the heart and travels upward 0.3 m to your shoulder, where it breaks into 3 smaller veins, each of radius 0.5 mm. Blood flows through the artery at a speed of 0.8 m/s as it leaves the heart. The density of blood is 1050 kg/m^3."
I determined that the blood moves at 1.07 m/s in the smaller veins, which is correct.

I am suppose to find the difference in pressure "between a point in the artery just as it leaves the heart and a point in one of the smaller veins just at the point where they split off"
I am pretty sure I am suppose to use bernoulli's Eqn.

P1 + d*g*y1 + 1/2 *d*v1^2 = P2 + d*g*y2 + 1/2 *d*v2^2
P1 + (1050 kg/m^3)(9.8 m/s^2)(0.3m) + (1/2)(1050kg/m^3)(0.8m/s)^2 = P2 + 0 + (1/2)(1050kg/m^3)(1.07m/s)^2

I have everything to use this equation, but the initial pressure. Am I missing a way to figure that out? I can't seem to get any of my pressure equations to work for this, P = F/A, P = P0 + dgh

The answer is suppose to be 3341 pascals
 
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The initial pressure is not needed. The difference in pressure is equal to (P2-P1), usually abbreviated as \Delta P.
 
What CRAZY individual thinks up an exercise where Bernoulli's equation is to be used on blood flow?

Blood is an extremely viscous fluid, and the arteries with so small radii, that any information gained from using Bernoulli's equation is guaranteed to be dead wrong.

At the very least, Hagen-Pousseille flow should be used as a base modelling tool (that's probably inaccurate as well).
 

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