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Two fixed, horizontal, parallel plates are spaced 0.4 in. apart. A viscous liquid (μ = 8 × 10-3 lb·s/ft2, SG = 0.9) flows between the plates with a mean velocity of 0.3 ft/s. The flow is laminar. (a) Determine the pressure drop per foot in the direction of flow. (b) What is the maximum velocity in the channel?

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Final answer:

The question requires applying principles of fluid mechanics to calculate the pressure drop and maximum velocity in a laminar flow between two plates given the viscosity, specific gravity, mean velocity, and plate separation.

Step-by-step explanation:

The student's question relates to the study of fluid mechanics, specifically the laminar flow of a viscous liquid between two parallel plates.

To map the problem to a conceptual model, we refer to the equation for the pressure drop ∆P in a laminar flow between two plates, which can be derived from the Navier-Stokes equations and is given as ∆P = (μ × 2U)/(h²), where μ is the dynamic viscosity, U is the mean velocity, and h is the separation between the plates. Given the values μ = 8 × 10-3 lb·s/ft², U = 0.3 ft/s, and h = 0.4 in. (converted to 0.0333 ft.), we can calculate the pressure drop per foot.

The maximum velocity (umax) in the channel for a laminar flow occurs at the center and is given by umax = 1.5 × U, where U is the mean velocity. Therefore, the maximum velocity in the channel can also be calculated using the given mean velocity.

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