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buoyant term in vorticity equation

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Old   September 16, 2002, 01:54
Default buoyant term in vorticity equation
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junomian
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Buoyant term in the vorticity transport equation is described as (Pr * Ra * dt/dx)

Discretizing this buoyant term,

Pr * Ra * [T(i, j) - T(i-1, j)]/dx .

In the simulation of the natural convection with bottom heating(T=1: bottom boundary, T=0: upper boundary), when we set the initial condition as isothermal T=0, then "T(i, j) - T(i-1, j)" is always zero, and convection does not begin for a long.

How to treat this buoyant term and equations ?

(Though I am not good at English, I will try to write as well as possible.)
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Old   September 17, 2002, 05:28
Default Re: buoyant term in vorticity equation
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D.M. Lipinski
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Junomian,

From the very start of your simulation, the dT/dx will not be zero close to the bottom boundary, because at the bottom boundary T=1 and the initial guess elsewhere is T=0. Therefore the convection effects, depending on the thermodynamic properties of the fluid and Ra value, should be clearly visible in your simulation.

regards

DML
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