Fluid Mechanics: Fundamentals and Applications
4th Edition
ISBN: 9781259696534
Author: Yunus A. Cengel Dr., John M. Cimbala
Publisher: McGraw-Hill Education
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Chapter 6, Problem 35P
An unloaded helicopter of mass 12,000 kg hovers at sea level while it is being loaded. In the unloaded hover mode, the blades rotate at 550 rpm. The horizontal blades above the helicopter cause a 18-m-diameter air mass to move downward at an average velocity proportional to the overhead blade rotational velocity (rpm). A load of 14,000 kg is loaded onto the helicopter, and the helicopter slowly rises. Determine (a) the volumetric airflow rate downdraft that the helicopter generates during unloaded hover and the required power input and (b) the rpm of the helicopter blades to hover with the 14000-kg load and the required power input. Take the density of atmospheric air to be 1.18 kg/m3. Assume air approaches the blades from the top through a large area with negligible velocity and air is forced by the blades to move down with a uniform velocity through an imaginary cylinder whose base is the blade span area.
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An unloaded helicopter of mass 12,000 kg hovers at sea level while it is being loaded. In the unloaded hover mode, the blades rotate at 550 rpm. The horizontal blades above the helicopter cause a 18-m-diameter air mass to move downward at an average velocity proportional to the overhead blade rotational velocity (rpm). A load of 14,000 kg is loaded onto the helicopter, and the helicopter slowly rises. Determine (a) the volumetric airflow rate downdraft that the helicopter generates during unloaded hover and the required power input and (b) the rpm of the helicopter blades to hover with the 14,000-kg load and the required power input. Take the density of atmospheric air to be 1.18 kg/m3. Assume air approaches the blades from the top through a large area with negligible velocity and air is forced by the blades to move down with a uniform velocity through an imaginary cylinder whose base is the blade span area.
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Chapter 6 Solutions
Fluid Mechanics: Fundamentals and Applications
Ch. 6 - Express Newton’s second law of motion for rotating...Ch. 6 - Express Newton’s first, second, and third laws.Ch. 6 - Is momentum a vector? If so, in what direction...Ch. 6 - Express the conservation of momentum principle....Ch. 6 - How do surface forces arise in the momentum...Ch. 6 - Explain the importance of the Reynolds transport...Ch. 6 - What is the importance of the momentum-flux...Ch. 6 - Write the momentum equation for steady...Ch. 6 - In the application of the momentum equation,...Ch. 6 - Two firefighters are fighting a fire with...
Ch. 6 - A rocket in space (no friction or resistance to...Ch. 6 - Describe in terms of momentum and airflow how a...Ch. 6 - Does it take more, equal, or less power for a...Ch. 6 - In a given location, would a helicopter require...Ch. 6 - Describe body forces and surface forces, and...Ch. 6 - A constant-velocity horizontal water jet from a...Ch. 6 - A horizontal water jet of constant velocity V from...Ch. 6 - A horizontal water jet from a nozzle of constant...Ch. 6 - A 2.5-cm-diameter horizontal water jet with a...Ch. 6 - A 90 elbow in a horizontal pipe is used to direct...Ch. 6 - Repeat Prob. 6-20 for the case of another...Ch. 6 - A horizontal water jet impinges against a vertical...Ch. 6 - Water enters a 7-cm-diameter pipe steadily with a...Ch. 6 - A reducing elbow in a horizontal pipe is used to...Ch. 6 - Repeat Prob. 6-24 for the case of = 125°.Ch. 6 - A 100-ft3/s water jet is moving in the positive...Ch. 6 - Reconsider Prob. 6-26E. Using appropriate...Ch. 6 - Commercially available large wind turbines have...Ch. 6 - A fan with 24-in-diameter blades moves 2000 cfm...Ch. 6 - A 3-in-diameter horizontal jet of water, with...Ch. 6 - Firefighters are holding a nozzle at the end of a...Ch. 6 - A 5-cm-diameter horizontal jet of water with a...Ch. 6 - Prob. 33PCh. 6 - A 3-in-diameter horizontal water jet having a...Ch. 6 - An unloaded helicopter of mass 12,000 kg hovers at...Ch. 6 - Prob. 36PCh. 6 - Water is flowing through a 10-cm-diameter water...Ch. 6 - Water flowing in a horizontal 25-cm-diameter pipe...Ch. 6 - Prob. 39PCh. 6 - Water enters a centrifugal pump axially at...Ch. 6 - An incompressible fluid of density and viscosity ...Ch. 6 - Consider the curved duct of Prob. 6-41, except...Ch. 6 - As a follow-up to Prob. 6-41, it turns out that...Ch. 6 - Prob. 44PCh. 6 - The weight of a water tank open to the atmosphere...Ch. 6 - A sluice gate, which controls flow rate in a...Ch. 6 - A room is to be ventilated using a centrifugal...Ch. 6 - How is the angular momentum equation obtained from...Ch. 6 - Prob. 49CPCh. 6 - Prob. 50CPCh. 6 - Prob. 51CPCh. 6 - A large lawn sprinkler with two identical arms is...Ch. 6 - Prob. 53EPCh. 6 - The impeller of a centrifugal pump has inner and...Ch. 6 - Water is flowing through a 15-cm-diameter pipe...Ch. 6 - Prob. 56PCh. 6 - Repeat Prob. 6-56 for a water flow rate of 60 L/s.Ch. 6 - Prob. 58PCh. 6 - Water enters the impeller of a centrifugal pump...Ch. 6 - A lawn sprinkler with three identical antis is...Ch. 6 - Prob. 62PCh. 6 - The impeller of a centrifugal blower has a radius...Ch. 6 - An 8-cm-diameter horizontal water jet having a...Ch. 6 - Water flowing steadily at a rate of 0.16 m3/s is...Ch. 6 - Repeat Prob. 6-66 by taking into consideration the...Ch. 6 - A 16-cm diameter horizontal water jet with a speed...Ch. 6 - Water enters vertically and steadily at a rate of...Ch. 6 - Repeal Prob. 6-69 for the case of unequal anus-the...Ch. 6 - Prob. 71PCh. 6 - Prob. 72PCh. 6 - A spacecraft cruising in space at a constant...Ch. 6 - A 60-kg ice skater is standing on ice with ice...Ch. 6 - A 5-cm-diameter horizontal jet of water, with...Ch. 6 - Water is flowing into and discharging from a pipe...Ch. 6 - Indiana Jones needs So ascend a 10-m-high...Ch. 6 - Prob. 79EPCh. 6 - A walnut with a mass of 50 g requires a force of...Ch. 6 - Prob. 81PCh. 6 - Prob. 82PCh. 6 - A horizontal water jet of constant velocity V...Ch. 6 - Show that the force exerted by a liquid jet on a...Ch. 6 - Prob. 85PCh. 6 - Prob. 86PCh. 6 - Water enters a mixed flow pump axially at a rate...Ch. 6 - Prob. 88PCh. 6 - Water enters a two-armed lawn sprinkler along the...Ch. 6 - Prob. 91PCh. 6 - Prob. 92PCh. 6 - Prob. 93PCh. 6 - Prob. 94PCh. 6 - A water jet strikes a moving plate at velocity...Ch. 6 - Water flows at mass flow rate m through a 90°...Ch. 6 - Prob. 97PCh. 6 - Water shoots out of a Iar2e tank sitting a cart...Ch. 6 - Prob. 99PCh. 6 - Prob. 100PCh. 6 - Prob. 101PCh. 6 - Consider water flow through a horizontal, short...Ch. 6 - Consider water flow through a horizontal. short...Ch. 6 - Prob. 104PCh. 6 - Prob. 105PCh. 6 - Prob. 106PCh. 6 - The velocity of wind at a wind turbine is measured...Ch. 6 - The ve1ocity of wind at a wind turbine is measured...Ch. 6 - Prob. 109PCh. 6 - Prob. 110PCh. 6 - Prob. 111PCh. 6 - Consider the impeller of a centrifugal pump with a...Ch. 6 - Prob. 113PCh. 6 - Prob. 114P
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