Consider a fluid flowing perpendicular and over a long cylindrical body and the free stream velocity described by equation U(x) = 2 Uinf sin (x/R) where R=D/2 is the radius of the cylinder.
For a laminar flow in the boundary layer, calculate the local friction factor and heat transfer coefficient as a function of x using momentum and energy integral equations, beginning at x=0 until separation occurs.
Determine the Nusselt number NUD = hD/k, as a function of phi=x/R, for the Reynolds numbers of ReD = 40,000 , 70,000, 10,000 and 140,000.
In: Mechanical Engineering
3. Describe step-by-step brittle fracture of some metals and ceramics with poor ductility and toughness. In discussion highlight and use relevant terms such as transgranular, Chevron pattern and others.
Text Book- The Science and Engineering of Materials, Askeland et al. (seven edition
In: Mechanical Engineering
The flow rate of warm air into the air conditioning is 5,000 cfm. An air conditioning system takes outdoor air at 95 degrees F dry-bulb and 70% relative humidity, and discharges it at 60 degrees F dry-bulb and 95% relative humidity. The air conditioning system operates on a vapor compression cycle using R134a between 20 and 200 psia. Refrigerant enters the compressor at 20 degrees F and leaves the compressor at 180 degrees F. Refrigerant enters the evaporator coil at a quality of x = 0.3. Determine a) The quantity of water removed from the air, in lb/min. b) The quantity of heat removed from the air, in tons. c) The mass flow rate of refrigerant, in lb/s. d) The compressor's power requirement, in hp.
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fluid mechanics question:
Why do birds have long narrow wings?
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A solid sphere of radius R is rotating with angular velocity w (omega) in otherwise still infinite fluid of density p (rho) viscosity u (mu).
(a) For creeping flow assumptions to hold, which condition(s) has to be satisfied?
(b) Under creeping flow assumption, solve the velocity field in the flow. Does the solution still satisfy the creeping flow assumption at the far field?
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how do you make an engineering and true stress-strain curve given the displacement (mm) and force (N)
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(Chapter 10)
Q: Explain the difference between coarse and fine pearlite?
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only for field engineers please: why would you choose to this segment "measurement while drilling"?
why would you choose " well completion"?
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(Materials Testing Results)
Q: The 30% rubber group reported Rockwell numbers for fresh 48 hour and old as 12.5,21.5, and 88.5. How do you explain these results?
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(Materials Testing Results)
Q: The 30% rubber group reported a strain at yield of 0.38 and a strain at break of 0.3. Please explain this change.
In: Mechanical Engineering
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A helical compression spring has 14 active coils and the free length is 12.5in. The outside diameter is 7/16 in and the spring has squared and ground ends. The end plates are constrained to be parallel. The material is music wire with presetting. The wire diameter is 0.042 in. Determine: (1) for static conditions compute the spring index, the solid length, the stress when the spring is compressed to the solid length. Check if static yielding occurs while the spring is brought to its solid length; (2) for dynamic conditions with Pmin=0.9 lb and Pmax=2.9 lb, check if the spring experiences torsional endurance limit fatigue torsional yielding, or torsional fatigue failure. Assume a survival probability of 90%, unpeened coil, and fatigue failure based on 50x103 cycles
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Using Excel, plot the internal temperature of a computer chip k=1.38 W/(m-K) that generated 2,000 W of power. The chip is 10 cm wide. Assume one side is at 40oC and the other is at 45oC
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The mean diameter of the square threaded screw having pitch of
10 mm is 50 mm. A load of 20 kN is lifted through a distance of 170
mm. Find the work done in lifting the load and the efficiency of
the screw, when
1. The load rotates with the screw, and
2. The load rests on the loose head which does not rotate with the
screw.
The external and internal diameter of the bearing surface of the
loose head are 60 mm and 10 mm respectively. The coefficient of
friction for the screw and the bearing surface may be taken as
0.08.
In: Mechanical Engineering
Find an important engineering failure that involves some of the topics discussed in MSE 350. Describe the failure, why it occurred, the damage (human, environmental, and economic) and the changes that could have been made in the design to avoid the failure. Was the failure caused by lack of engineering knowledge at the time, engineering error, or management/government error? Discuss!!
For each of the following common items, identify what they are commonly made of, the material type (composite, metal, semiconductor, polymer , ceramic, glass. Describe why that material type is used. Include at least two references for your answers (websites are fine, but try and find good ones). If more than one material type is used in the items, include them all! Be careful to use proper engineering vocabulary when answering this question!
Abrasives for grinding metal
Automobiles Integrated circuits
Airplanes Bridges
Solar panels
Latex paint
Soda bottles
Polyvinylchloride (PVC) plumbing pipe
In: Mechanical Engineering