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Old   September 9, 2004, 06:38
Default Convection Term Discretization
  #1
Maciej Matyka
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<table width="50%"> <td> Hi,

I would like to ask about one of my problems which I have doing the new free surface code.

I am trying to implement one of high order schemes - VONOS, and found that sometimes people discretize only one part of convection term with higher order schemes, and sometimes they discretize both. I mean i.e. u momentum equation with two part convection term: - d(uu)/dx - d(vu)/dy. In a paper of Sean McKee et. al.:

"High-order upwinding and the hydraulic jump", Num. Meth. in Fluids

they are discretizing only d(uu)/dx with high order scheme and d(vu)/dy is discretized by centered scheme. On the other side - Griebel et.al. developed NaSt3d code where both parts of the convection term are discretized with high order scheme. Who is doing it good?

I should add, that I tested both discretizations, still have problems with my code and need to be sure that that part of the code (core of it) works well to test next parts of it. And last questions - regarding free surface and high order schemes - am I right when apllying the First Order Upwind near the surface or should I derive expressions from other high order schemes to treat convection near free surface? </td> </table>

Thank you, Maciej Matyka <A HREF="http://panoramix.ift.uni.wroc.pl/~maq/eng/">http://panoramix.ift.uni.wroc.pl/~maq/eng/</a>
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Old   September 9, 2004, 21:58
Default Re: Convection Term Discretization
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Junseok Kim
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In a paper of Sean McKee et. al.:

"High-order upwinding and the hydraulic jump", Num. Meth. in Fluids

It looks like they use high order discretization, would you be more specific about the pages?

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Old   September 10, 2004, 02:47
Default Re: Convection Term Discretization
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Maciej Matyka
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Yes, they do use hogh order approximation and apply it for all terms - I was wrong, now it is clear to me. Sorry.

M.
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Old   October 7, 2004, 04:32
Default discretization of Navier Stokes Eqns
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Nil Gurbuz
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Hi I am a phd student in math. working on Navier stokes equations I am mainly working on finite difference schemes I wonder whether it is possible to use finite difference discretization with staggered grid but not the control volume method ? I also confuded about how to approximate the fictious points outside the boundary for pressure and V velocities

Thanks

Nil Gurbuz
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