Unformatted text preview: GENO JDl A RD? 2635th Mid term #2 (Nov. 13) l. (5.60) Air flows into the narrow gap, of height h, between
closely spaced parallel disks through a porous surface as
shown (see Fig. 1). Use a control volume, which outer surface
located at position r, to show that the uniform velocity in the r direction is V, =(r/2h)U (U is the zcomponent of ﬂow velocity at the porous surface). Find an expression for the velocity component in the zdirection. Evaluate the components
of the acceleration for ﬂuid particle in the gap. Assume that the
air is incompressible. (25 points) 2. (6.25) The radial variation of ﬂuid velocity between two
cylindrical sections of radii R1 and R2 (see Fig. 2) is given by
V30) = UlRl Ir (where U1 = const.). Derive the expression for the pressure difference, AP, between the outer and inner
boundaries of the flow. Express your answer in terms of ﬂuid mass density, p, velocity U1, and radii R1 and R2. 25 points) 3. (6.64) The water level in a large tank is maintained at height
H above the surrounding level terrain. A rounded small nozzle
placed in the side of the tank discharges a horizontal jet (see
Fig. 3). Neglecting friction, determine the height h at which the
nozzle should be placed so the water strikes the ground at the maximum horizontal distance X from the tank. (25 points) x. 4. (7.19) The power, W, required to drive a fan is believed to depend on ﬂuid density, p. impeller
diameter, D, and angular velocity of the fan, 03. use dimensional analysis to determine the dependence of W on other variables. (25 points) ...
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 Fall '07
 Krashinov

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