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Development thermal boundary layer

by engineerings
Tags: boundary, development, layer, thermal
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Chestermiller
#19
Jan7-14, 01:54 PM
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Quote Quote by a_potato View Post
If you model inviscid flow you use Euler equations. The energy equation does not contain heat conduction or any viscous stress terms, only the pressure work and energy advection. Using Euler equations for compressible inviscid flow there is no thermal conductivity unless you include that term in the energy equation.
Who says that the energy equation does not include conduction? The mechanical energy balance equation, of course, does not include heat conduction, but the overall energy balance equation certainly does. You need to learn the distinction between these two. See Transport Phenomena by Bird, Stewart, and Lightfoot, Chapter 11. They also cover the thermal energy balance equation, which is the difference between the two.

Chet
a_potato
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Jan7-14, 02:07 PM
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I am fully aware of the difference between thermal and mechanical energy, and that the Euler equations effectively only consider mechanical energy balance, not diffusivity
Chestermiller
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Jan7-14, 02:52 PM
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I am fully aware of the difference between thermal and mechanical energy, and that the Euler equations effectively only consider mechanical energy balance, not diffusivity
The Euler equations also figure indirectly in the thermal energy balance equation, in that the viscous dissipation terms (i.e., zero viscosity) are zero for an inviscid fluid, thus leading to a thermal balance between heat conduction and advection. The version of the differential thermal energy balance that I wrote in a couple of posts ago applies the thermal energy balance equation to the problem of heating an inviscid fluid in axial tubular flow. This is very basic stuff.

Chet
a_potato
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Jan7-14, 04:07 PM
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The Euler equations do not have thermal conductivity. Zero viscosity and non-zero thermal diffusivity in NS equations provide energy balance between advection and diffusion. This is very basic stuff
Chestermiller
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Jan7-14, 04:16 PM
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The Euler equations do not have thermal conductivity. Zero viscosity and non-zero thermal diffusivity in NS equations provide energy balance between advection and diffusion. This is very basic stuff
I think it would be best if we continue our discussion in private messages. This has gotten a little too contentious for me. We need a less threatening format to try to reach a consensus. I will be contacting you in private messages.

Chet


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