Prova di esame ATP 10 Febbraio 2021

(1 min) If v is the velocity field, the dyadics vv is

• A symmetric tensor

• An anti-symmetric tensor

• An isotropic tensor

• vv is not a tensor

• irrotational

• rotational

• it depends on the value of A

• none of the other answers

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(3 min) A Newtonian liquid flows under laminar flow conditions between two horizontal parallel plates. If the two plates are quiescent and a pressure difference is applied between the two ends of the channel, one has, along the channel thickness:

• a linear tangential stress profile and a quadratic velocity profile

• a linear tangential stress profile and a linear velocity profile

• a constant tangential stress profile and a linear velocity profile

• a constant tangential stress profile and a parabolic velocity profile

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• The flow rates in the two tubes can never be equal

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• Q²/(2gS²)

• Q/(2gS)

• Q²/(2S²)

• gS²/(2Q²)