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March 28, 2013, 17:40 |
Questions on a pressure profile
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#1 |
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I have some questions on a pressure profile obtained from a simple 2D laminar pipe flow.
Please look into the attached .jpg image of the pressure contour Could some one please provide clarifications to the following questions I have - As the flow proceeds from the inlet, there is a gradual pressure drop. Could this be solely attributed to the frictional losses due to wall shear ? The bernoullis theorem doesn’t seem to hold good here because it is expected that the pressure should increase as the cross sectional area increases for the flow, however a pressure drop is witnessed from the plot. Could you please explain the limitation of bernoullis theorem in this case
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March 28, 2013, 18:19 |
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#2 | |
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Filippo Maria Denaro
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March 29, 2013, 06:03 |
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#3 |
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Thank you very much for your response. I've gone through some books and found that it's a case of Poiseuille flow and I understand that Bernoullis theorem is not applicable here as it is a viscous flow (the flow has a very low reynolds number Re < 1 so the viscous effects clearly dominate the inertia). Yes the pressure drop is due to the viscous shear , the shear stress acts in a direction opposite to the flow and a pressure drop from inlet to outlet is required to counter balance this.
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