- #1

Gwozdzilla

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## Homework Statement

Blood supply to the heart occurs through coronary arteries. Consider one of the arteries to be 2.5 mm in diameter and 3 cm in length. The average velocity of blood flow through that artery is 1.5 cm/s. Assuming the density of blood to be 1.056 g/cc and viscosity to be 3 cP (3x10-3 Ns/m2). Estimate the shear stress at the wall.

## Homework Equations

τ = μ ∂u/∂y = shear stress = (viscosity) (d(velocity))/(dy)

## The Attempt at a Solution

τ = (3cP)(1.5cm/s)

I'm not sure how to estimate ∂u/∂y. Is it equal to the average velocity? I think that when the blood reaches fully developed flow, it's shaped like a parabola and it's velocity is constant at a given y, but I'm not sure how to apply this information to understand the formula.