8/10/2019 Taller 3 Mecanica de Fluidos

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UNIVERSIDAD DISTRITAL FRANCISCO JOS DE CALDASLICENCIATURA EN FSICA

FACULTAD DE CIENCIAS Y EDUCACINMecnica de Fluidos 4718-902

Taller 3. Esttica de Fluidos con sistemas en movimiento e Integrales relacionadas a Volumen deControl

Octubre 08 /14

Msc. HOLMAN J. MESAFecha de entrega: Viernes 17 de Octubre en grupos de 4 personas y en hojas blancas carta.

1. The tank of liquid in Fig. accelerates to the right with the fluid in rigid-bodymotion. (a) Compute ax in m/s2. (b) Why doesnt the solution to part (a) depend

upon the density of the fluid? (c) Determine the gage pressure at pointA if thefluid is glycerin at 20C.

2. The same tank from previuos Prob . is now moving with constant acceleration upa 30 inclined plane, as in Fig. P2.141. Assuming rigid-body motion, compute (a) the value of the acceleration

a, (b) whether the acceleration is up or down, and (c) the gage pressure at pointA if the fluid is mercury at 20C.

3. The tank of water in Fig. is 12 cm wide into the paper. If the tank is accelerated to theright in rigid-body motion at 6.0 m/s2, compute (a) the water depth on sideAB and (b)the water-pressure force on panelAB. Assume no spilling.

4. The tank in Fig. P2.146 is filled with water and has a vent hole at pointA. The tank is 1 m wide into the paper.Inside the tank, a 10-cm balloon, filled with helium at 130 kPa, istethered centrally by a string. If the tank accelerates to the right at 5m/s2 in rigid-body motion, at what angle will the balloon lean? Willit lean to the right or to the left?

5. A gravity-driven liquid jet issues from a slot in a tank, as in Fig. an approximation forthe exit velocity distribution , where h is the depth is of the jetcenterline. Near the slot, the jet is horizontal, two-dimensional, and of thickness 2L, as

shown. Find a general expression for the total volume flow Q issuing from the slot;then take the limit of your result if

6. at 20C flows steadily through a closed tank, as in Fig. . At section 1,D1 = 6 cm and the volume flow is 100m3/h. At section 2,D2 = 5 cm and the average velocity is 8 m/s. IfD3 = 4 cm, what is (a) Q3 in m3/h and(b)

average V3 in m/s?

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7. In Fig. the exit nozzle is horizontal. If losses are negligible, what should the waterlevel h cm be for the free jet to just clear the wall?

8. The pump in Fig. P3.144 creates a 20C water jet oriented to travel a maximumhorizontal distance. System friction head losses are 6.5 m. The jet may beapproximated by the trajectory of frictionless particles. What

power must be delivered by the pump?

9. A 20C water jet strikes a vane mounted on a tank with frictionless wheels, as inFig. The jet turns and falls into the tank without spilling out. If = 30, evaluate

the horizontal forceF required to hold the tank stationary.

10. The model car in Fig. weighs 17 N and is to be accelerated from rest by a 1-cm-diameter water jet moving at 75m/s. Neglecting air drag and wheel friction, estimate the velocity of thecar after it has moved forward 1 m.

11. Air at 20C and 1 atm flows in a 25-cm-diameter duct at 15 m/s, as in Fig. The exitis choked by a 90 cone, as shown. Estimate the force of the airflow on the cone.

12. A jet of liquid of density and areaA strikes a block and splits into two jets, as in Fig. Assumethe same velocityV for all three jets. The upper jet exits at an angle and area A. The lowerjet is turned 90 downward. Neglecting fluid weight, (a) derive a formula for the forces (Fx, Fy)required to support the block against fluid momentum changes.(b) Show that Fy = 0 only if 0.5. (c) Find the values of and for which both Fx and Fyare zero.

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