transport mechanism involving bulk motion of a medium

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Heat loss via convection

Suppose I have a glass container (trough) and I want to heat the water inside. I put it on a hot plate. Now, even though the hot plate is at $110\,^{\circ}C$, the liquid only reaches $50\,^{\circ}C$. ...
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108 views

Can convection cells evolve in stably stratified fluid?

Assume stably stratified fluid but not in equilibrium, e.g. with non-constant temperature gradient for example. Can convection cells be present? Typical example of convection cells is Rayleigh–Bénard ...
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2k views

Finding electric power generated using heat transfer

I'm working through an example I have been given to study. Suppose I have a 2m X 4m photovoltaic panel on my roof that is irradiated with a solar flux of $G_s = 700W/m^2$. Given: $\alpha_s = 0.83$ ...
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21 views

Is there a difference between solid-to-fluid convection and fluid-to-fluid convection?

I found an online calculator relating to convective heat transfer, but the calculator's description says it's for heat transfer between a solid surface and a moving fluid. However, the definitions ...
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39 views

flat plate isoflux convection - how to calculate temperature

I am an engineer trying to design a simple 1D program for evaluating the temperatures of a multi-layer heatsink that includes convection and radiation heat transfer from the external surface. For a ...
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1answer
83 views

Series of parallel thermal resistance connection for this enclosure?

Let's say that I have an 2D enclosure in the shape of a pyramid with unequal areas for the faces and I am looking to determine in the inside air temperature. The parameters I know are the outer and ...
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Numerical Solution of the Propagation-Dispersion equation

I have asked this question on Computational Science and also on Mathoverflow, but no satisfactory answers so far. I thought maybe the physics community could shed some insight on the issue. I am ...
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0answers
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Vanishing viscosity in eqn. of heat transfer for free convection: on what argument?

In Landau's and Lifshitz' Fluid Mechanics on the derivation of the equation of heat transfer for free convection p. 218, they write In the thermal conduction equation (50.2), the viscosity term ...
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Forced convection: temperature gradient in conical pipe

My situation involves a conical pipe of known dimensions and material composition. Warmer-than-ambient air is added to the small end at a steady, known flow rate. I'm hoping for a way to estimate ...
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Vertical wall at 3 different temperatures - do the same natural convection coefficient correlations apply?

I have an vertical enclosure that consists of 3 shelves, each with its own temperature and are thermally isolated from each other. We will call the shelves A, B, and C with A being the base shelf. The ...
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Extension of the advection diffusion equation with diffusion perpendicular to the flow

Assume you model particle flow in fluid in a cylinder by an advection-diffusion equation, thus taking into account both diffusion and bulk flow. What would happen to the model if you would, at some ...
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51 views

Heat transfer through convection in human body

How does the heat transfer takes place in human body through convection in these two situations. 1) when environment temperature is less than body core temperature($37^0C)$, say it is around $25^0C$. ...
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How can I get the boundary and initial conditions of the convection–diffusion equation consistant?

I want to solve the 1D convection–diffusion equation. The boundary conditions are a flux in from the bottom and a flux out on the top. Furthermore I want no concentration inside at the beginning. I ...
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Heat flow through a pipe

I have a pipe, in which a cooling medium flows through it. I would like to know the temperature of the cooling medium at different lengths of the pipe. Is there an equation to relate the length and ...
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0answers
19 views

Why is the boundary layer thinner on the outside of an outer wall versus the wall inside the house

The convection on the outer suface of the outer wall of a house is larger, because outside a house it's more windy compared to inside. More wind means more turbulence which leads to more transfer of ...
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0answers
42 views

How complex is an energy balance for this problem?

Let's say I have an enclosed room in the shape of a box with forced airflow on the outer walls at an ambient temperature. Each end of the room (forward and rear) has a vent that ducts in warm air to ...
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0answers
221 views

What is the minimum volume in which, for a given temperature difference $\Delta T$, natural convection would occur?

I'm trying to figure out if convection will occur in a plastic bottle slice and what length of slice would be optimal to achieve high R value transparent insulation on the cheap. The bottle slice is ...
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0answers
396 views

Determine pipe outlet temperature without length?

Let's say I am flowing a fluid through a pipe that has a constant surface temperature. Is it possible to determine the heat flux on the inner surface without knowing the pipe's length when the only ...
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118 views

Fluid mechanics Grashoff number

When I derived the Grashof number (for natural convection at a vertical plate) starting with the ratio of buoyancy forces to viscous forces, I realized that I had set the Reynolds number to 1 (ie I ...