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B Would greater flow take precedence over velocity in pressure

  1. Feb 4, 2017 #1
    The equation for mean arterial pressure = flow * resistance, however, if we increase flow we would increase velocity by the equation Velocity = flow/ cross sectional area, and velocity would decrease pressure according to bernoullies law?

    Which would take precedence in generating more pressure on the arterial walls?
     
  2. jcsd
  3. Feb 4, 2017 #2

    jbriggs444

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    Bernoulli is for "inviscid" flow -- no resistance. You have a pipe with approximately the same pressure at inlet and outlet and find that the pressure varies depending on the flow velocity. Center of the constrictions = low pressure. Wide points = ambient pressure.

    An equation for pressure = flow * resistance assumes the opposite. A viscous flow. You have a pipe with a constriction. Upstream of the constriction you have a high pressure, downstream you have low pressure. The pressure drop scales with flow and with resistance. Upstream of constriction = high pressure, downstream = low pressure.

    An artery is pretty much by definition "upstream" of a viscous restriction (the capillaries).

    [Caveat: I have zero real world experience with medicine, blood pressure and fluid dynamics]
     
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