How Does Blood Pressure Change with Velocity in Fluid Mechanics?

AI Thread Summary
The discussion centers on calculating the blood pressure difference in an artery segment using Bernoulli's equation, given a change in flow velocity from 0.2 m/s to 0.6 m/s over 0.025 seconds. The artery is assumed to have a constant cross-section, with blood treated as an incompressible fluid. One participant notes the need to apply Bernoulli's equation for unsteady flow and considers the assumption of uniform acceleration, although they express uncertainty about the linearity of blood velocity changes. The importance of including applicable equations and a detailed solution attempt is emphasized. Overall, the conversation highlights the complexities involved in fluid dynamics calculations related to blood flow.
Edson_arantes
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I have a question about fluid mechanics. I know it's not completely physics, but in the end, it involves physics:

Suppose you are computing the blood flow in an artery segment with length 3 cm and diameter 3 mm. The artery has a constant cross section and its positioned horizontally in your computation. Assume the density of the blood to be 1,000 kg/m3. Blood is incompressible. At some point in your computation, in a time period of 0.025 s, the average flow velocity you specify at the artery inlet changes from 0.2 m/s to 0.6 m/s. Based on the Bernoulli's equation, at the middle of that time period, what do you estimate/expect the blood pressure difference between the artery inlet and outlet ?

Thanks
 
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Edson_arantes said:
I have a question about fluid mechanics. I know it's not completely physics, but in the end, it involves physics:

Suppose you are computing the blood flow in an artery segment with length 3 cm and diameter 3 mm. The artery has a constant cross section and its positioned horizontally in your computation. Assume the density of the blood to be 1,000 kg/m3. Blood is incompressible. At some point in your computation, in a time period of 0.025 s, the average flow velocity you specify at the artery inlet changes from 0.2 m/s to 0.6 m/s. Based on the Bernoulli's equation, at the middle of that time period, what do you estimate/expect the blood pressure difference between the artery inlet and outlet ?

Thanks
Hi Edson_arantes. http://img96.imageshack.us/img96/5725/red5e5etimes5e5e45e5e25.gif

These forums require that along with quoting the textbook question you also write the applicable equations, and that you include your attempt at the solution. Your effort here is somewhat lacking. Please remedy this.
 
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So, I used the Bernoulli's equation for unstedy flow, then I assumed that the acceleration is uniform (but i think it's wrong). Taking the constant acceleration, I measured the distance the blood traveled in the middle of the time (0.0125s) and the velocity in the beginning and at t = 0.0125s. Then, I just substituted in the formula. The problem is that I don't think it's this simple, because the blood velocity may not vary linearly.
 

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