A cylindrical aluminum core is surrounded by a titanium sleeve, and both are attached at each end to a rigid end-plate. Set up t
he fundamental equations and combine them in displacement-method order to solve for the following:
a) the elongation of the composite bar if the entire structure is heated by 1000F. Assume that the core and the outer sleeve are both stress free at the reference temperature.
b) the axial stress induced in each material.
a) the elongation of the composite bar if the entire structure is heated by 1000F. Assume that the core and the outer sleeve are both stress free at the reference temperature.
b) the axial stress induced in each material.
1 answer:
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Answer:
(b)False
Explanation:
Given:
Prandtl number(Pr) =1000.
We know that
Where is the molecular diffusivity of momentum
is the molecular diffusivity of heat.
Prandtl number(Pr) can also be defined as
Where is the hydrodynamic boundary layer thickness and
is the thermal boundary layer thickness.
So if Pr>1 then hydrodynamic boundary layer thickness will be greater than thermal boundary layer thickness.
In given question Pr>1 so hydrodynamic boundary layer thickness will be greater than thermal boundary layer thickness.
So hydrodynamic layer will be thicker than the thermal boundary layer.